# Pontiac 400 Overheating Concerns



## Andrew69 (Dec 28, 2017)

Hello good Pontiac people. Last year you helped me out while I was working on a guy's '67 GTO with the 400 and auto transmission. That one is finished and returned to the owner.

A couple of months ago I took on a project to complete the build of a friend's '67 Firebird with the Pontiac 400 and a 700R4 transmission. One problem he has is it quickly overheats. Reading about this it seems the big cube Pontiac engines often have this problem.

Anyway, I have rebuilt the suspension with new springs front and rear, installed the side glass and door panels and the remainder of the interior. Now I've turned my attention to tuning and the over heating.

This an engine he had built by a local builder who has (had, since he is now deceased) a good reputation. It looks nice under the hood, but the owner has no specs of the internal components. The shop tells me they purge their records after 2 years so I really don't know what's in it.. :frown3: The engine seems to be mostly stock, or maybe a mild cam, based on observing it running.

I found the timing too advanced and set it to 34 BTDC at 3,000 & greater. I found the distributor clamp bolt was bottoming out before the clamp secured the distributor. That has been corrected. The engine pulls about 17in vacuum at idle and the vacuum advance is all in at 14in. I moved the vacuum advance connection from the Port vacuum to Manifold vacuum on carb. He has an Edelbrock carb that I've set the air-fuel mixture screws using the vacuum gauge. He has a factory fan shroud on a 4-row aluminum radiator with a 5 blade flex fan. The flex fan has 3/8" diameter clearance on one side and nearly 2" clearance on the opposite side. :frown3: It was sitting really deep inside the shroud so I replaced the 2" fan spacer with a 1" spacer. Anything thinner and the fan blades hit the power steering pump pulley bolt.

With the tuning it runs hot but less aggressively than before. My most recent improvement was to install a FlowKooler hi-Flow water pump. https://www.summitracing.com/parts/bra-1649 This car has no heater core but had the hose connecting the rear passenger head to the timing chain cover. My thinking was this circulates hot coolant through the system without filtering through the radiator, so this morning I removed the jumper hose and plugged both ends.

I topped off the coolant after first filling it though the opened thermostat location, replaced the thermostat, and let the engine run with the radiator cap off to burp the engine. When the temp gauge reached about 175 the engine began to vibrate and coolant sloshed out the radiator. I turned off the engine and let things cool off again. After I topped off the radiator I ran it again with the 16 lb radiator cap back on. It seems when the thermostat opens there is a vibration that sounds like it is from the water pump or thermostat. Does the heater core hose provide a sort of relieve valve that allows some circulation even when the thermostat is closed? Should I put the jumper hose back? Or is this air in the system that is somehow hammering when the thermostat opens? Even though I spilled some coolant when draining and changing the water pump it didn't require any additional to top it off.

I've invested a lot of time on this engine and want to get it under control. I know this isn't a GTO but I hope you guys will still assist. I'll be glad to answer any specific questions. I am stumped. :crying:

Update: I topped off the coolant, raising the radiator coolant level a couple inches, replaced the cap and tested it again. It started the rattle again at 157 degrees and then it reoccurred with no apparent relation to the thermostat opening. It got to 192 degrees then settled back down to about 186. The cooling concern seems better but now the rattle. It reminds me of water hammer in an older house when you turn off the water and it hammers inside the wall. Is this related to the heater hose bypass shut off?


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## PontiacJim (Dec 29, 2012)

If you keep filing the radiator and top it off each time before starting, it will push anti-freeze out each and every time and you will be doing that to eternity.

Does the top of a radiator has an expansion tank? Or is it a crossflow with the tanks on the side (which I think they had)? Water expands when hot. The level will be down about 1 1/2 or so on a radiator with a top expansion tank each time you look at it after it cools. As long as you see some water above the core tubes, you are good. The water level will find its own level. Same goes with the side tanks, let the water find its level and then check - you should be able to look in and see it not too far down on the side.

I would also suggest a laser temp gun to verify the engine/radiator running hot. It may not be.

As to the noise, never heard of that one before. May be a problem with the FlowKooler installation - something expands when hot and is now hitting/wrapping on something.


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## cij911 (Oct 25, 2017)

Sorry if I missed it, but what kind of radiator are you using and what thermostat? As far as fans go, I did not have great luck with the flex fans. My car runs significantly cooler with a large aluminum radiator , stock water pump and 180* thermostat, and stock fan (with crappy shroud). I drive the car hard in 90*+ weather and never see anything more than ~190-200. Obviously it gets hotter when I park the car.


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## Andrew69 (Dec 28, 2017)

It is an aluminum 4 row radiator with a 180 degree thermostat that was tested in a pan on the stovetop. I was successful in capturing this rattle on video and loaded it to YouTube. This rattle may or may not be related to the overheating concerns. It is a recently occurring concern.

This morning I replaced the heater core bypass hose and with the thermostat removed I filled the radiator with coolant until the thermostat cavity was full. I installed the thermostat and then topped the coolant to several inches below the cap.

I started the car and backed it out onto the 5 degree incline leading to the garage. I know someone said no angle is needed, but if it pukes out I would just as well it be outside where I can easily wash it away.

There I let it idle for 20 minutes while I observed the fluid flowing in the radiator and the car gradually heating. It never puked out and was flowing pretty well. The heat seemed to be in control but then gradually went to 203 degrees before I shut it down.

The intermitted chatter continued with no obvious pattern related to thermostat opening or oil pressure dropping. The oil pressure remained between 56 and 65 depending on my revving the throttle or resting idle. This video captures the noise between the 11 second and 29 second span. If this won't play go to YouTube and search for Pontiac 400 Rattles to see the video directly.


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## BLK69JUDGE (Jun 10, 2010)

looks like a blade is ready to break on the fan

that fan doesnt look original... I dont think our pontiacs ever used a 1" spacer...
leads me to believe its the wrong fan ...

is it bent or out of balance .... ???

was the water pump divider plate clearanced ??

Scott


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## Andrew69 (Dec 28, 2017)

It’s an aftermarket 5-blade flex fan with a 1” spacer to set the distance from the power steering pump. If it were replaced what would be preferred? I didn't build this engine or select the components. I am working to overcome the overheating concerns.

The water pump divider plate was clearances to ~ 0.060 space. Removing it to see if there is interface isn’t a quick job. The noise seems to be coming from the body of the engine and the driver’s side. Best that I can tell.

What about that rattle? Is it related to air in the block or a more serious problem with the engine?


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## BLK69JUDGE (Jun 10, 2010)

ok....
it looks like a reproduction of the factory flex fan ,,, thats a good one ...

have you fired it up with NO belts and reved it up ?

hmmmmm

real nice n tidy engine bay ...

could it be the alternator ,,,, like some one forgot the spacer behind the cooling fan 

it looks like it needs a correct 69 front alternator strap ,,

sometimes we go to ac pulleys .. large on the bottom smaller water pump ,,, seems to help low rpm cooling,,,

....

hmmmmmmm

gotta get back to work


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## PontiacJim (Dec 29, 2012)

Because it kicked on and then kicked off, I am going to say it is the alternator when the charging cycle kicks in.


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## Lemans guy (Oct 14, 2014)

Sounds like the fan hitting the shroud, or touching a belt. Also make sure the fan mounting bolts are not or have not worked loose, that will give a knock like that. I would examine all around the shroud and the belts and see if the fan is flexing out and barely striking something, look on the bottom of the shroud good. The shroud sits in a little groove at the radiator bottom and if not set in right could ride high.

You can remove belts one at a time to try to isolate the noise, likewise you could remove the shroud, try it for a minute, remove the fan try it for a minute, remove a belt etc. if the noise is eliminated you can investigate further.

It looks like your fan is out the back of the shroud, but hard to tell. Anyway it should be half in and half out for proper cooling, too far in or out of the shroud will make it run hot....

Stay with it you will get it, I would eliminate the moving parts, fan, belts, pulleys first.....if the sound is not there, put your stethoscope or rubber hose to the valve covers and engine....rockers, pushrods etc....but on the video, sounds like it is up front.....:nerd:


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## Dano628 (Jun 18, 2019)

Lemans guy said:


> Sounds like the fan hitting the shroud, or touching a belt. Also make sure the fan mounting bolts are not or have not worked loose, that will give a knock like that. I would examine all around the shroud and the belts and see if the fan is flexing out and barely striking something, look on the bottom of the shroud good. The shroud sits in a little groove at the radiator bottom and if not set in right could ride high.
> 
> You can remove belts one at a time to try to isolate the noise, likewise you could remove the shroud, try it for a minute, remove the fan try it for a minute, remove a belt etc. if the noise is eliminated you can investigate further.
> 
> ...


Sounds like the fan hitting the shroud to me .


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## Andrew69 (Dec 28, 2017)

Thank you BLK69JUDGE for the confirmation the fan is a reproduction of an original design and is a good choice for usage.



PontiacJim said:


> Because it kicked on and then kicked off, I am going to say it is the alternator when the charging cycle kicks in.


Today I am going to disconnect the alternator to determine if this is the cause.



Lemans guy said:


> Sounds like the fan hitting the shroud, or touching a belt. Also make sure the fan mounting bolts are not or have not worked loose, that will give a knock like that. I would examine all around the shroud and the belts and see if the fan is flexing out and barely striking something, look on the bottom of the shroud good. The shroud sits in a little groove at the radiator bottom and if not set in right could ride high.
> 
> You can remove belts one at a time to try to isolate the noise, likewise you could remove the shroud, try it for a minute, remove the fan try it for a minute, remove a belt etc. if the noise is eliminated you can investigate further.
> 
> ...


I did observe the fan and other moving parts and they all seem to clear. The fan is tightly secured, the bolts are tight. If the engine is turning a constant RPM why would the fan make contact with the shroud for ~ 15 seconds every few minutes? The fan is about 60% into the shroud, under higher RPMs when the blades flatten out there is minimal extending out of the shroud. If I move it any closer to the engine it will hit the power steering pump pulley bolt.



Dano628 said:


> Sounds like the fan hitting the shroud to me .


I have not tried a stethoscope but it seems to be coming from the driver's side valve cover or deeper into the engine. As stated above I've verified the fan is not hitting anything, and if it was it wouldn't be toggling off and on like this. I know in a video it is more difficult to analyze than on site. This engine has blue colored aluminum rocker arms. Could one of these be going bad? While this problem surfaced while I am working on the cooling system but it could be unrelated to the cooling.

What kind of engine problems might cause this rattle? The oil pressure and RPMs remain constant during these bouts of noise. I would take the car for a drive and try to "drive out" the steam pocket, but don't want to unnecessarily harm the engine.


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## Lemans guy (Oct 14, 2014)

:nerd:zz Good, so you have eliminated the fan, belts and pulleys....

If you have an automatic transmission, sometimes the 3 flywheel to torque converter bolts get loose and make a similar knocking sound...

You can lay down next to the car and listen right at where the torque converter is between engine and trans.....

If you think the sound is there, it is an easy fix usually. Drop the flywheel cover. (That could rattle too if loose)......

There are 3 bolts that hold the flywheel to torque converter, check for looseness.

This sound may come in and out as the torque converter is spun hydraulically by the trans fluid, so the loose bolts may vibrate sometimes and not others.

Check this and rocker arms for looseness etc. Remove the valve cover and check for broken springs or loose rocker arms etc. you may be able to find it.

Good Luck :nerd:


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## geeteeohguy (Feb 2, 2008)

Whatever it is, it looks like the engine has a misfire. It's rough all the time. Have you had a vacuum gauge on it?


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## Dano628 (Jun 18, 2019)

Andrew69 said:


> Thank you BLK69JUDGE for the confirmation the fan is a reproduction of an original design and is a good choice for usage.
> 
> 
> 
> ...


If it has blue rocker arms they probably roller rockers and they might be hitting the valve covers. You could remove the valve covers and check inside the covers and rocker arms for signs of impact. What I don’t understand is if it was the rockers hitting the valve covers why it would come and go .


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## Andrew69 (Dec 28, 2017)

The engine runs pretty smooth when standing beside it. The video may be distorting the sound or mixing in the exhaust noises.

I took a few days off from working on this car. We still have temps in the mid 90s and I don't like hanging over a hot engine during those temps.

Yesterday I got under the car to check the torque converter bolts and the cover. It isn't the cover because there isn't one. Rule that out. All three torque converter bolts are tight. Rule that out.

This morning I ran the car with the hot wire disconnected from the alternator. The temperature rose to the 180s with no rattles. I shut it down and reconnected the alternator. The rattle resumed as before. Disconnected the alternator and it's silent. Re-connect and it returns.

This seems unrelated to the cooling system concerns.

Placing a long screwdriver point against the valve covers and alternator, and my ear against the butt end of the handle, reveals no additional internal noise when the rattle is present. It is coming from the rear of the engine low on the driver's side. That is where the starter resides. What on the starter might be chattering when the alternator cycles? The solenoid? I've never heard of this happening. Could it be wired incorrectly? This has the American Autowire wiring with Dakota Digital dash carrier. Should I replace the solenoid? I'm glad it's isolated but what is my next step?


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## geeteeohguy (Feb 2, 2008)

With everything modified and changed, your next step is checking one circuit/component at a time. Glad you are closing in on it.....that right there is huge.


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## BLK69JUDGE (Jun 10, 2010)

{ real nice n tidy engine bay ...

could it be the alternator ,,,, like some one forgot the spacer behind the cooling fan

it looks like it needs a correct 69 front alternator strap ,,}


"Because it kicked on and then kicked off, I am going to say it is the alternator when the charging cycle kicks in."

pull the alternator .... have it load tested at napa ....

check the pulley to armature mating / mounting 

before you go 

post the information stamped in the top of the alternator please...

it may be your original ... Sorry about the crummy picture ....


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## Andrew69 (Dec 28, 2017)

The alternator is an after market chromed unit and I seriously doubt it is be original. The owner told me the car in its previous life was a drag car and came to him stripped and most of the sheet metal was replaced. Personally I am not a fan of chrome stuff under the hood unless it is factory original. But that's the alternator on there. I have also noted the seemingly mismatched alternator brackets and may address it after these other concerns are resolved.

I put the volt meter to the battery connections and there is no difference in voltage when the noise cycles through. Since the rattle is in the back of the engine and there is no spike or drop in the charging I don't see the alternator being the culprit. If I do remove it I'll check for any stampings.

I'll crawl under there to check out the starter and go from there.


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## BLK69JUDGE (Jun 10, 2010)

This morning I ran the car with the hot wire disconnected from the alternator. The temperature rose to the 180s with no rattles. I shut it down and reconnected the alternator. The rattle resumed as before. Disconnected the alternator and it's silent. Re-connect and it returns.


and you dont think its the alternator ? 

really .......... hmmmmmmmmm


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## O52 (Jan 27, 2019)

Noise has a funny way of transmitting. My Cadillac had an unusual noise in the front of the engine. Took it to Cadillac and they proclaimed the A/C Compressor bad. They replaced the compressor and the noise was still there. Took an old school mechanic to find it had a cracked flex plate. He stated that the noise would transmit up through the crankshaft to the front. Every time the compressor would cycle on it would stress the flex plate just enough to create the noise fooling the younger mechanic.


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## Andrew69 (Dec 28, 2017)

BLK69JUDGE said:


> This morning I ran the car with the hot wire disconnected from the alternator. The temperature rose to the 180s with no rattles. I shut it down and reconnected the alternator. The rattle resumed as before. Disconnected the alternator and it's silent. Re-connect and it returns.
> 
> 
> and you dont think its the alternator ?
> ...


So why do you want to bring logic into this discussion? :wink3: I took the alternator to CARQUEST for testing and was told it puts out 13.8v and they consider that low. But it ran smooth without any unusual noise. I then took it to Advance Auto and they declared it good. I witnessed that test and it runs smooth. I'll now put it back on the car.

Apparently the alternator cycling is causing some solenoid or something to chatter.


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## BLK69JUDGE (Jun 10, 2010)

*and*

ah yes the ole voltage regulator buzzzzzzzzzzzz clicking ....
havent had one do that in a long time .... it may be from the lazy alternator ....

making the points chatter... if it says delco remy on it ... dont throw it away ..
make sure the ground screws are clean for a good body ground ,,

and 13.4 is a little low I like 14.5 on my cars...

VR-175 from auto zone .... its a Wells solid state unit
they seem to have a good reputation ...

I just keep using the originals I have when I need one ...

Scott


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## tal002 (Sep 28, 2019)

*noise in engine compartment*

throw a rebuilt alternator on the car and i think your problem will be gone


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## Andrew69 (Dec 28, 2017)

I corrected the reported voltage above from 13.4 to 13.8 volts. Still low but closer to the 14v mark.

This is a one-wire alternator with an internal voltage regulator. I still looked for an independent regulator bolted on somewhere but none was found. Might replacing the alternator to get 14.5v rectify this problem?


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## PontiacJim (Dec 29, 2012)

Andrew69 said:


> I corrected the reported voltage above from 13.4 to 13.8 volts. Still low but closer to the 14v mark.
> 
> This is a one-wire alternator with an internal voltage regulator. I still looked for an independent regulator bolted on somewhere but none was found. Might replacing the alternator to get 14.5v rectify this problem?


I already told you what the noise was - the alternator cycling. My buddy has one of those 1-wire alternators on his 1970 Camaro and his made a racket just like that. His also turned out to be bad and he replaced it.

You won't find a voltage regulator used with that type alternator - it is internal. The original one would have been mounted up on the firewall. Who knows what the previous owner did to change the wiring. I had to figure out the wiring on my buddies car, but finally got it all working and running.

13.8 volts are meaningless if you don't know what the amp output is. Not knowing what brand you have, some of the 1-wire alternators don't kick in to charge until you get the RPM's past about 1500 RPM's, they don't put out at an initial idle, so you have to rev the engine up to reach the RPM that kicks in the charging process, then it will charge at idle.

Some will require a much larger power wire if a true 1-wire alternator. You need about a 4-gauge wire if it is connected to the battery. You also want to make sure you have a really good ground from the engine to frame.

Lot of info on the different types of 1 & 3 wire alternators and how to hook them up. Catalog

:thumbsup:


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## Andrew69 (Dec 28, 2017)

:wink3: Maybe I'm a slow learner.

We'll replace the alternator and I'll report back the results. I own a '69 Camaro with the factory design wiring with voltage regulator on the radiator bracket. That's what I am more familiar with and this newfangled stuff sometimes trips me up.

Okay, I'm looking at the local options for replacement of a single wire alternator. What minimal amperage should we get? I'm seeing 80 amp and 100 amp and others. Should we go with the max amperage offered?


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## PontiacJim (Dec 29, 2012)

Andrew69 said:


> :wink3: Maybe I'm a slow learner.
> 
> We'll replace the alternator and I'll report back the results. I own a '69 Camaro with the factory design wiring with voltage regulator on the radiator bracket. That's what I am more familiar with and this newfangled stuff sometimes trips me up.
> 
> Okay, I'm looking at the local options for replacement of a single wire alternator. What minimal amperage should we get? I'm seeing 80 amp and 100 amp and others. Should we go with the max amperage offered?



Make doubly sure it is the Alt., but being on this side of the screen is what I get from the video. Me, the cost of an alternator is not much and it eliminates another thing it could be, especially when it is someone else's project and things have been changed around. I would also examine the wiring to make sure things look correct. Where did the factory regulator and wiring/plug go? You may want to get a wiring diagram just to have on hand, if you don't already have one.

Also check to make sure you have all the ground wires on the car as "projects" often leave them off. Ground from the body (typically the firewall strap) and engine strap to frame.

The factory used about a 63 Amp Alt.. The output you want depends on any accessories you may want to install. Some will go the electric radiator fan route and that requires more amps, or a big watt stereo system, or other electrical options like power windows, seats, etc..

So all this comes into play if you think you may go that route in the future. The bigger the Amps, the more power the Alt. uses to spin it. So the 80-100 AMP Alt should be fine. I can't recommend a brand as everyone has their favorites. Make sure that the replacement Alt. has the same "clocking" of any of the plugs or lugs so as to match yours. 

Check out this YouTube video, and may have already watched. My buddy with the '70 Camaro ran his wire down to the starter for a cleaner/hidden look rather than having the wire hanging in the air going to the battery like in the Chevelle video: 




And here is a PDF on th TuffStuff 1-wire Alt. and their part numbers for the use of the Idiot light on the dash if you have one. https://www.tuffstuffperformance.com/files/pdf/1-wire_alternator_instructions.pdf

Then once you get the Alt/wiring right, then you can get back to the cooling issue if it still persists. :thumbsup:


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## 1968gto421 (Mar 28, 2014)

Subscribing, lots of great info here.


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## Andrew69 (Dec 28, 2017)

Today I installed a new single-wire alternator and the intermitted chatter remains. I'm seeing no improvement. As stated before it comes from the rear of the engine. Could the distributor be chattering? Could the starter solenoid chatter? There is something triggering it on and off.


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## PontiacJim (Dec 29, 2012)

Andrew69 said:


> Today I installed a new single-wire alternator and the intermitted chatter remains. I'm seeing no improvement. As stated before it comes from the rear of the engine. Could the distributor be chattering? Could the starter solenoid chatter? There is something triggering it on and off.



Hmmmm. Have you placed your hand on the alternator with the engine running and see if you feel any change in the alternator when you hear that noise? Being careful of moving parts, see if that isolates anything.

The thing that seems puzzling is what I heard as an "on" & "off" cycle. That to me sounds like electrical. 

IF it were the solenoid, it would be grinding on the flywheel ring gear. However, it could be possible that the starter gear is hung up or jammed and is not retracting. It will start the engine, but then goes for a ride on the ring gear because it is not pulling back off the gear. Usually if this happens, it has more of a "whine" sound as the starter gear is overspeeding. I don't know if you can drop the inspection cover on the bottom of th bellhousing and look up at the starter snout with a flash light to see anything out of place. 

While under there, I would pull all the plugs so the engine has no compression, and then have a helper rotate the engine looking for any loose flywheel to converter bolts, any cracks, or a bent flexplate. My brother had a flex plate bolt back out on his automatic and it would have a thudding noise and then not, intermittently until it backed out enough to thud all the time. I was afraid it sounded like a spun bearing. His buddy got it put up on a lift checking things and found the bolt, it was hitting the block as it went around. Damaged the mounting block on the torque converter and it had to be replaced. Put all back together the car has been fine since. 

You might want to consider getting a mechanic's stethoscope and use it in different areas of the engine when the sound kicks in. This may isolate and narrow your search. https://www.harborfreight.com/Mechanics-Stethoscope-63691.html I listened to the video again, and still sounds like something cycling on/off. I see the flex fan wavering a bit, but it wavers both with the sound off and the sound on. I don't see anything that stands out.

I see the PCV valve/hose to the carb. Does the valve covers have a breather on one side or the other? Just for fun, pull off the oil fill/breather caps and listen to see if the sound changes or you can hear it coming up from the engine.

Does it change when you run the engine above idle, like 2,500 - 3,000 RPM's?

I'm becoming stumped here, but the stethoscope may narrow the sound down. Keep at it, the answer has got to be somewhere. :thumbsup:


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## Andrew69 (Dec 28, 2017)

I've confirmed the flex plate to torque converter bolts are tight. There is presently no cover there to rattle. One thing I have not done is move the transmission from park to drive to see if anything changes. There are no chatter marks on the face of the flex plate teeth and the at rest the starter is not engaged.

It does have the PCV in the front of the intake and a filtered breather on the driver's side. I found the passenger side valve cover was open in the top where the inlet should be so I plugged that hole. I'm thinking the breather should be on the passenger side and the driver's side plugged. I don't see how that can make any difference but I just changed nonetheless.

I note the stethoscope you linked. I'll pick one up the next time I'm out as Harbor Freight is nearby. Using a long screwdriver as a stethoscope I've heard no difference of noise in the alternator or the valve covers during the chattering events. And felt no vibrations either. That's why I was hesitant to replace the starter but just maybe the starter was pulsating and causing something else to chatter. But that's not the case.


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## Mav (Mar 5, 2017)

Have no idea about noise but for the overheating try a high flow thermostat, it lowered the temp on my 69 RA3 20 degrees.


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## johny (Apr 11, 2017)

I listened to your youtube video and the sound reminds of an issue we had with our GTO. It took awhile to track down because everything seemed to be in order but the culprit on our car was the fan hitting the bottom of the radiator shroud. I attached an ad from a gentleman who advertises on the Pontiac Oakland Club site. He sells spacers that raises the engine so the fan clears the shroud. They worked on our car.

Take Care
John


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## Andrew69 (Dec 28, 2017)

Update: The high flow water pump, centering of the fan shroud around the fan and the 1" fan spacer, replacing a 2" spacer, seems to have the cooling concerns in control. The temp climbs to the upper 180s then thermostat opens and it remains in the lower and mid 180s. We've driven the car maybe 10 miles with the temp staying in control and I would now be confident to drive it further.

I thank everyone for the helpful hints on resolving this and the unusual noise. The fan has plenty of clearance all around, and the noise originates at the back of the engine on the driver's side. I suspect the starter solenoid is chattering for whatever reason.

I finished everything else on the car and today he took it home. He is going to have the guys who installed and set up the the engine investigate the noise. I don't have a lift, I work off jack stands when under a car. I opted to not pursue it further. When the cause is learned I will let you know.

Again, I thank you all for the help you've given me. I'm adding a photo of the car that I know isn't a GTO, but with a Poncho 400 it has the heart of a GTO.


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## PontiacJim (Dec 29, 2012)

Andrew69 said:


> Update: The high flow water pump, centering of the fan shroud around the fan and the 1" fan spacer, replacing a 2" spacer, seems to have the cooling concerns in control. The temp climbs to the upper 180s then thermostat opens and it remains in the lower and mid 180s. We've driven the car maybe 10 miles with the temp staying in control and I would now be confident to drive it further.
> 
> I thank everyone for the helpful hints on resolving this and the unusual noise. The fan has plenty of clearance all around, and the noise originates at the back of the engine on the driver's side. I suspect the starter solenoid is chattering for whatever reason.
> 
> ...


Nice Firebird. I had a 1967 around 1980 and it was my introduction to _fast_ Pontiacs - it had a warmed over 350 Pontiac, 3-speed on the floor.

Glad you got the engine temps under control. Sorry we could not seem to help with the noise you are still having. If you learn what it is, make sure you add to this post - I'm curious myself. :thumbsup:


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