# Engine Temp and aftermarket a/c



## xconcepts (Jan 4, 2009)

Does anyone know what the average engine temp is for a 66 GTO. Mine had a aftermarket temp gauge added and it runs between ~208 and ~218 degrees. Now I don't know how hot they normally run, but there is nothing wrong with the radiator, its oem and <2 years old, has the shroud around the fan, but the guy I bought it from though it would run hot but never overheated. 

Also, I'm looking at adding a aftermarket a/c unit since I am probably being stationed in AZ and its to damn hot not to have one. With the kits that are out there am I looking at needing an aluminum radiator or dual electric fans to keep it cooler? Has anyone added an a/c unit? Did she run hotter?


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## Koppster (Jul 27, 2008)

My 64 has a 76 400 in it with a 4 row radiator, shroud and standard fan, typically runs at 195.

I installed an after market AC (Vintage Air) a couple of months ago. 

I live in San Antonio TX, in stop & go traffic the temp will get up to 210 on a hot hot day (100+). Stays at 195/200 while cruising at 75 mph or less.

Not a problem but I am considering swapping out the thermostat to a 160 just to see if it improves the stop and go situation.

Rick


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## xconcepts (Jan 4, 2009)

See mine runs a little hotter and I know when I get the a/c that it will probably jump a little more. Guess I'm trying to see what I could do to get it a little cooler.


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## Koppster (Jul 27, 2008)

Are you sure your temperature gauge is reliable?

The suggestions I have heard include a good 160 thermostat, non-flex fan and shroud.

Aftermarket stuff to help includes the high flow water pumps, aluminum radiators and electric fans.


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## geeteeohguy (Feb 2, 2008)

And water wetter seems to help, too. You're right in the ballpark. These engines run on the warm side, especially if bored .060" or more. As long as it's not puking, expect it to run 210-215 with A/C on a hot day. If you run hotter than 225-230, you need additional cooling.


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## jetstang (Nov 5, 2008)

208 -218 cruising, or stuck in traffic? If it's not really hot, it shouldn't go over 200 at speed. I would do a good flush, 160 or 180 stat, 180 is better for the winter, then see where you are. You have to get your temps down before considering AC on the car.


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## xconcepts (Jan 4, 2009)

She sits at about 210 crusing, little higher in traffic. Thats in Orlando, FL. I'll see if the thermostat is original or not and look into the water wetter.


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## Eddie.w (Nov 30, 2008)

Are these temps for the '66 or for pretty much all years? I have a '69 w/a 400 that's pretty much stock and am just curious what temp it should be running at. I've added an Autometer water temp guage so I think it's pretty acurate.


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## NC_Mike (Jun 2, 2009)

*Hot 64, and not in a good way*

My 64 was running 230 if I was on the highway for more than 10 minutes, and that is with my aftermarket air off. In stop and go traffic it would get up to 210-215, once again without the air on. Actually I haven't been able to use my a/c more than a minute or two on hot days at red lights to cool off. So in efforts to cool down my Goat I am replacing the rear end to a 3.08 to lower the RPM's, replacing the water pump and radiator, and am considering switching to a 160 thermostat. I'm not sold on that though, Ames seems to think that it would open too early and wouldn't properly cool, I'm thinking if it opens a little earlier it would help cool it down before it got too hot. Also I am adding water wetter. So if all of this doesn't fix I don't know what to do. I realize it is a shotgun approach to cooling, but I can't stand a car that won't start or over heats. Any other suggestions out there??


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## Koppster (Jul 27, 2008)

Electric fans (double type)....but, I would try the radiator, pump and thermostat first

Gotta ask, what do you have for a rear end? 

I don't see how changing your gear ratio is going to help, more rpm should increase fan speed and water flow.


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## xconcepts (Jan 4, 2009)

So I figured I'd start with the thermostat, 160 or 180 though? Then the water pump and electric fans and if that doesn't work aluminum radiator. Also will be adding water wetter.


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## NC_Mike (Jun 2, 2009)

I switched from a 3.55 to a 3.08. When I would drive at highway speeds my RPM's were around 3400-3500 and the temp in less than ten minutes would spike to over 230, and that is with the air off and "clean" air as the NASCAR guys would say. When I would get off of the highway it would cool down to around 210 to 220. I figured that the high revs had to be a big part of the overheating, and I don't want to run a 45 year old engine that many RPM's. So I figured while the mechanic is in there we might as well to an overhaul on the cooling system, better to be safe than sorry right?


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## xconcepts (Jan 4, 2009)

So I found out a 195 tstat is currently in her and was replaced in the last 6 years or so, not sure but its not very old. Would I be better off going with a 180 tstat or keeping the 195?


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## geeteeohguy (Feb 2, 2008)

I've ALWAYS run a 160 degree stat. Every GTO I've owned in the past 30 years has thanked me for it. There is no reason to run a 195 degree stat in ANY vintage Pontiac engine.


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## Rukee (Feb 8, 2007)

geeteeohguy said:


> I've ALWAYS run a 160 degree stat. Every GTO I've owned in the past 30 years has thanked me for it. There is no reason to run a 195 degree stat in ANY vintage Pontiac engine.


If your running a higher compression engine it will have a more complete cyl burn with the 195* over the 160*.


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## geeteeohguy (Feb 2, 2008)

True, the hotter an engine runs the more efficient it is. No doubt. But, if it runs so hot that it detonates and pings with pre-ignition, all bets are off. I've found that my GTO's seem to do better with the 160 stats. My cars run at 195--220 degrees with new cores in their 4 row radiators, fan shrouds, and flex fans., with 160 'stats. My previous GTO's have all been 10.75 compression 389's, with the exception of one 400 engine and one 428. Also, the climate in CA is a factor....it almost never gets to freezing, and it's never gone near 0! More often, it's at 100 degrees around here.


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## khinton (Jun 22, 2008)

ames is correct --You want to hold back the water in the rad longer as that is where the cooling takes place --not in the engine it self (a 180 will usually keep the temps lower than a 160) go figure


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## busaben (Oct 30, 2008)

not meaning to hi-jack the thread, but how hard was it to install your aftermarket a/c for those that has? and how did you cover up the hole in the firewall? my 67 had a/c, but some of the parts are long gone. and is there any real difference in hotrodair and vintage air? hard to find a pontiac compressor bracket for the new style comp?


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## xconcepts (Jan 4, 2009)

So for the south, IE: TX, AZ, FL etc a 180 will do me better than the 195?


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## jetstang (Nov 5, 2008)

I'm in FL and I like the 160 stats, but you don't get much heat in the "winter". A 180 stat will give you heat in the winter, and still run cooler in the summer. Try a 180, if it's still runs hot, then go 160. I never run a 195. My 454 SS runs 190 in the summer w/180 stat. I just put a new compressor on my AC and the temp jumps to 210 immediatelly. I put a pusher electric fan on it w/ the manual fan and it still tries to go to 220. And I put a huge aluminum radiator in it. I may go to 160 stat. I think my condensor fins are too bent and blocking flow, but thats another story. And it has a flex fan on it, wish I could find the stock clutch fan for it.


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## Koppster (Jul 27, 2008)

busaben said:


> not meaning to hi-jack the thread, but how hard was it to install your aftermarket a/c for those that has? and how did you cover up the hole in the firewall? my 67 had a/c, but some of the parts are long gone. and is there any real difference in hotrodair and vintage air? hard to find a pontiac compressor bracket for the new style comp?


busaben

I had Automania in New Braunfels TX install my Vintage Air system, I'm pretty certain they used the 64-66 Chevelle/Nova/El Camino kit with some mix and match on the vents. http://www.vintageair.com/08/catalog08/08 VA Cat pg 42 f.pdf

I am very happy.

I could have easily gone with Hot Rod Air, about the same price and Hot Rod even has a better warranty; however, Automania was in the habit of Vintage Air. I live within 3 miles of both companies and from what I saw, there is little to no difference in the two.

http://www.gtoforum.com/f12/vintage-air-installed-20632/

PS: The complete kit & installation ran me $2,500.00. Might sound pricy but I wanted it right.


Rick


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## busaben (Oct 30, 2008)

looks great, most likely what i will go with.


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## NC_Mike (Jun 2, 2009)

*It is cool now!!*

My cooling problems have been fixed!! Thanks for all of the great input guys!! I can't pinpoint what the cure was, but here is what I did. I lowered the rear end gear to a 3.08, this lowered the rpm's which will lower the heat. Then we replaced the radiator, water pump, added a 160 thermostat, adjusted the timing (I think it was advanced some, I can't remember), and added the Water Wetter.

So before 10 minute trip on the highway the temp would get up to 235-240, in town it would be about 205-215; and that was without the a/c running. I was hating not being able to use the vintage a/c that I had installed on these hot days of the summer. When I would stop the car and turn it off it would get up to 240-250ish. SCARY with an original engine for sure. 

Now the rpm's are great at higway speed, speedo still doesn't work so I have to be sure not to lead the pack but to go with the traffic. You can actually have a conversation with someone while driving. The temp on the highway w/o the air is about 175-180; w/ air it is about 190. In traffic w/o air it is running 170-175, w/ air it can get up to about 195. 

I couldn't be more pleased with the way that it is running, now I don't nervously stare at the gauges. Now the next project is interior during the winter and find a painter for new paint job next year.


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## Mikes66GTO (Feb 4, 2009)

Hi busaben,

I know I'm late on this thread, but I purchased my aftermarket A/C from Classic Auto Air - 1964 - 1967 GTO-Lemans Air Conditioning System | 64 - 67 Pontiac AC . It took me about 8 hours, but I purchased the "Perfect Fit" system they offer and they are right, no cutting, just remove the old heater assembly and bolt theirs in. It even has a low horsepower compressor so I don't even need an idle solenoid to jack up the idle.

Hope this helps.

Mike


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## skuzzzusmcdevildog (May 8, 2009)

*well i got a 69 gto*

i run a 73 400 trans am motor with a tri core 1000hp radiator from campions i think its called any way i run about 160 to 165 in stop and go traffic and about 156 to 158 at night in georgia heat ! i tpk the thermostat out cause it ran 190 and i wanted it cooler and wala !!:cool


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## xconcepts (Jan 4, 2009)

Just an update on my heating problem, switched out to the 160 tstat and have been told she's running at 190-205 highway and traffic. That's before the water wetter

arty:


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