# $200.00 Reward



## goat670 (Aug 10, 2008)

I Will Pay Anyone 200.00 If They Can Tell Me How To Stop My 1967 Gto 400 Auto From Overheating. The Only Thing Left To Do Is A Last Resort Is To Add Electric Fans. I Have Done Everything Poss. To Cool This Beast.engine Is Just Done 8 Miles On It, 2nd Rebuild Due To Rings Did Not Seat On 1st Rebuild, Poss A Result Of Also Running Too Hot During Break-in.


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## 05GTO (Oct 6, 2004)

Have you;

Moved the fan closer to the radiator with a Mr. Gasket adapter?
Changed the water pump to a high flow water pump?
Are you running a stock t-stat?
Have you verified the lower hose is not going flat while the engine is running?
Is the heater coil connected?
Are you using a fan shroud?
Verified the t-stat is installed correctly?

If any of these help, give the reward to a charity,


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## Richard Boneske (Jul 29, 2008)

Pontiac engines always run hot right after rebuild. I've had this on every one I've done. If you can drive it at a steady speed of about 30-50 mph for 25 miles or so, it will get better. In addition to the good tips above---

Do you have antifreeze in at about 50-50 mix? Plain water doesn't cool the engine as well. 

Make sure timing is advanced enough at idle. Also, vacuum advance helps prevent overheating. 

Is the impeller in the water pump the high profile one for better circulation?


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## crustysack (Oct 5, 2008)

what kind of radiator??? old stock or new 4 core aluminum- that will make a HUGE difference- also a shroud is a MUST to pull the air through the radiator,


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## 66tempestGT (Nov 28, 2009)

just curious, how hot is overheating. my cars and trucks run 200ish.


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## Rukee (Feb 8, 2007)

66tempestGT said:


> just curious, how hot is overheating. my cars and trucks run 200ish.


I'm thinking the same thing. Were are you getting your temp reading from and what is the temp while running??
All good tips up there and all worth checking out, like moving the fan closer to the radiator, fan shroud is a must, and it must fit good too, close to the fan blades so if forces the air to come through the radiator. Have you removed the radiator cap and run till the thermostat opens and verify that the coolant is in fact flowing through the system??


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## Jerry64 (Apr 20, 2010)

I have always split the angle of the fan blade with the edge of the shroud,1/2 in and 1/2 out......JB.


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## geeteeohguy (Feb 2, 2008)

How to keep your car from overheating? Don't start it up. You can send the $200 to your local ASPCA. There are a lot of good threads on this subject here and on the PY forums. One thing that's critical is water pump impeller to backing plate clearance. Needs to be no more than 1/8" or so. Normal Pontiac operating temps in my experience are between 200-225 degrees in the summer and a little less in the winter, out here in CA. This is data gathered from MANY '60's Pontiacs over more than 30 years.


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## Thumpin455 (Feb 17, 2010)

Im with geeteeohguy, it should be getting over 200 unless you are running a very cold T stat, pretty much anything under 220 should be good and wont hurt a thing. I was going to mention the plate behind the pump but he did that, so second it.

If you are running the original 670 heads you could be having issues with timing if you have flat tops and pump gas. Unless you are at high altitude or with a cam that bleeds lots of cylinder pressure it will have inaudible detonation. You will have to retard the timing to get it not to rattle and that will not help an over heating condition. 

Also running very lean or very rich can cause it to run hot.

In my 70, before I put it on yeast pee that runs really cool, I ended up going with a BeCool radiator, electric fans, 195 T stat, and a new pump. It also needed retuned for South Carolina after moving from Nebraska. 

If you are running an aftermarket intake manifold you can have a problem with the crossover mismatch that creates a cavitation in the coolant that reduces flow, along with bubbles. Make sure the crossover opening isnt too small or offset from where the passage in the heads is located. I had to fix a Performer, a TorkerII, and the RPM now on the 70.

Lastly the trans cooler can impart quite a bit of heat if you have a stall in it or there is something causing the line pressure to be too high so the pump makes more heat than it should. If a clutch is slipping that can also make lots of heat, or a band that doesnt fully disengage, anything that can cause friction.

Bring up here to the UP and we can mess with it for a day or two and figure it out.


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## goat670 (Aug 10, 2008)

well lots of great info. radiator has been modifed with additional fins and tubes, equivalant to a 6 core. Shroud and all afore mentioned items have been done. spring in the hose,new divider plates, flow kooler w/pump, new heater core,trans brand new also, no slippage.timing set properly and carb stock, 4bbl,rebuilt and ok.
However, this evening I installed a (arggghh) plastic flex fan. did not use the shroud, but will install. set timing to 36 degrees at 3500 rpm and went for a ride. went to 210 in 15 minutes idling in driveway 1st. upon driving it settled down to 180 !! still not running just right however, but looks like some progress. If all it took was a $30.00 cheap ass fan I'm gonna be real relieved and pissed!






Thumpin455 said:


> Im with geeteeohguy, it should be getting over 200 unless you are running a very cold T stat, pretty much anything under 220 should be good and wont hurt a thing. I was going to mention the plate behind the pump but he did that, so second it.
> 
> If you are running the original 670 heads you could be having issues with timing if you have flat tops and pump gas. Unless you are at high altitude or with a cam that bleeds lots of cylinder pressure it will have inaudible detonation. You will have to retard the timing to get it not to rattle and that will not help an over heating condition.
> 
> ...


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## Chris Holabaugh (Jan 18, 2009)

You can do what I did, because of the increase in horsepower I put a Rodney Red radiator in and have not had a problem since.


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## Eric Animal (Oct 28, 2007)

If you have the proper 8 bolt timing cover, do you have BOTH plates in with the water pump, and is all the air out of the system??


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## GTO JUDGE (May 14, 2005)

When I purchased my car I replaced the Tstat with a 180* one. It ran at like 195 and at idle 200-225. Over the winter while working on it I replaced it with a 160* high flow Tstat from NAPA. So far this season it runs at about 165* and at idle 170*. I haven't seen if go past 175*. The warmest I've driven it so far was on a few days it was close to 80*. The real test will be in the dead of summer but so far I am liking what I am seeing. I was told if I went with a 160* I'd get little heat. When I needed the heat it was throwing plenty of warm air. 

I have the standard shroud, flex fan with the adapter, and 12 ounces or so of Water Wetter. 50-50 mix anti-freeze.


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## jetstang (Nov 5, 2008)

If a cheap flex fan fixed the problem, then it sounds like your stock fan clutch was bad. Does your old clutch have resistance or spin free on the bench? The clutch engages with heat, but still should have some resistance. Either way, replace the clutch and put it back on, stock fans are better than flex fans and don't cut you so bad if you get your hand in there by mistake.


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## goat670 (Aug 10, 2008)

update...ran well all day, little hot in traffic, shroud will not be able to be used, next is to add some spacers to the fan to get closer to radiator.Engine is breaking in and continues to run better and better. no leaks either


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## goat670 (Aug 10, 2008)

Rodney Red . What do they offer?



Chris Holabaugh said:


> You can do what I did, because of the increase in horsepower I put a Rodney Red radiator in and have not had a problem since.


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## goat670 (Aug 10, 2008)

new stainless plates and correct timing cover with flow cooler pump



Eric Animal said:


> If you have the proper 8 bolt timing cover, do you have BOTH plates in with the water pump, and is all the air out of the system??


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## goat670 (Aug 10, 2008)

no fan clutch being used currently





jetstang said:


> If a cheap flex fan fixed the problem, then it sounds like your stock fan clutch was bad. Does your old clutch have resistance or spin free on the bench? The clutch engages with heat, but still should have some resistance. Either way, replace the clutch and put it back on, stock fans are better than flex fans and don't cut you so bad if you get your hand in there by mistake.


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