[71 T/A]

My 69 GTO with Turbo 400 and stock converter has the original 400 with a small Comp 212/212, 440/440 cam. I have a fairly new Griffin radiator, stock water pump with clearanced good impeller, stock clutch fan with Hayden fan clutch, 3.08 gears, Qjet, stock distributor, 12 degrees initial, advance in by 2400.

When moving car will run 165-175. But stop at a light and the temps will soar until the car is moving. If I'm at a long drive through, temps will keep going past 210 until I shut the a/c off and then the temps will stop rising instantly. Then when the car starts moving, the temps start dropping again. Car does not leak water and I'm using a high flow 160 Robert Shaw thermostat. Even tried with no thermostat or just the body of one. No difference.

Would electric fans help? A new Flowkooler or Edelbrock water pump?

[GOLDOHC]

Sounds like there isn't enough air moving through the radiator at idle. Do you have a shroud?

[Squidward]

I am facing similar symptoms in my 67 FB. I am currently running a Taurus electric fan.

During triple digit heat it will slowly climb up to 210 during 45-50 mph cruising.

My install of the electric fan behind my 2 core aluminum rad stopped my idle heatup, so it solved an idle airflow deficiency. It will idle all day long in 110 degree heat.

When I start cruising, temps will start rising. I too have done all of the basic checks and mods, including using tstat or no tstat. I think I have an airflow issue now at cruise speed only. I've already optimized the timing.

Have you made sure all air is vented from the system?

Is there anything under the hood to disrupt the airflow, or allow it to bypass the radiator? That is what I was theorizing last time I worked on that car.

[1969GTO]

I have read most of there threads with cooling problems.
my 69 GTO non-ac car, a bunch of mods and it's an automatic and 3.90 gears, I have never had a cooling problem.
I read most people are using a clutched fan, I don't.
My cooling system is all stock except for a 4 core radiator [copper] and the Koolflow water pump,stock shroud,stock fan [original],stock hoses,no extra cooler for the trans and a 160 stat.
Never an issue moving or sitting....maybe the trick stuff ain't so trick.

[66bonne]

71 T/A: I also live in scorching, searing, scalding Florida. However, I have no overheating problems with my Catalina. I run an electric water pump and an electric fan with shroud. That way the water flow is always constant rather at idle or WOT, at the track or on the street.

Jim

[Nicks67GTO]

67 GTO 455. Ebay Aluminum radiator, stock water pump, HD hayden clutch, stock fan, shroud and 160* stat and I dont think iv'e ever seen over 180. Im usually at 170ish. I dont have AC yet however.

[ta man]

Get the car up to 180 plus,put a plastic bag in front of the grill the fan should suck it in...almost sounds like a bad clutch fan?

[chrisp]

Ditch the clutch fan they do not pull air @ idle / sitting . Use a good 2 1/2" pitch flex fan , no noise & strong air mover @ idle .

[ANDYA]

What size water pump pulley do you have? A large pulley will make the water pump spin too slow at idle (at a stop light) and not circulate the coolant fast enough. Once you start to move the pump spins faster, the coolant starts to circulate and you see the temperature begin to drop.

[71 T/A]

I have a shroud and the correct pulleys for an a/c car. My car runs cool without the a/c on. It's when you turn on the air is when the temps start climbing.

Chrisp, I tried a 7-blade flex fan with good pitch (Flexalite 1818) and it did not help.
66Bonne, which electric water pump did you use? I spoke to Stewart Componenets and they say it's water flow and not air flow that's causing my hot idling issues.

[Formulajones]

Originally Posted by ANDYA

What size water pump pulley do you have? A large pulley will make the water pump spin too slow at idle (at a stop light) and not circulate the coolant fast enough. Once you start to move the pump spins faster, the coolant starts to circulate and you see the temperature begin to drop.

That was my first thought, since I was wondering if this was a factory AC car or AC that's been added. Aftermarket air seems to be all the rage these days without thought to pulley ratios.

If it's the latter, then it would have come with a larger diameter water pump pulley from the factory slowing it down. The AC cars had a much smaller pulley to move the coolant faster.

I use the smaller pulley trick on "non" AC cars for some extra coolant movement, stock water pumps, 160 stats with 3/16" by-pass hole drilled, copper core 4 core radiators, and everything else stock. With proper timing settings, vacuum advance working, carburator calibrated properly, I never see temps over 175, and the cars with AC I never see temps over 185-190ish with the AC blasting in the Arizona heat. Even a 600+ HP pump gas car I have here with AC and 4.10 gears won't get hot, using a stock clutch fan.

71T/A, you could try a pusher fan as a bandaid that might work for you, but looking at pulley ratios would be my first suggestion, then possibly the clutch fan. In extreme cases if all else fails I'd suggest the OEM style 7 blade 18" direct drive flex fan. They can be found at swap meets for ~$20 and pull a ton of air, they are however HP robbers But they cool nicely. I have several here, and could post a picture for reference if need be.

[Formulajones]

Originally Posted by 71 T/A

I have a shroud and the correct pulleys for an a/c car. My car runs cool without the a/c on. It's when you turn on the air is when the temps start climbing.

Chrisp, I tried a 7-blade flex fan with good pitch (Flexalite 1818) and it did not help.
66Bonne, which electric water pump did you use? I spoke to Stewart Componenets and they say it's water flow and not air flow that's causing my hot idling issues.

Ah, you posted this while I was typing the last post.

Correct pulleys then. I've never had luck with Flexalite fans or any aftermarket direct drive fan, they just don't pull enough air. I'll get a pic up of the OEM style fans I'm talking about. You could try an aftermarket pump to push more water if you wish, however I've never found the need for them, even on very radical street engines.

For reference, although my fathers 69 goat is a non AC car, he runs a 571 cubed pontiac that just made 700+ HP and TQ on the dyno, 3.73 gears, 4 core copper radiator, stock water pump, stock clutch fan and shroud, 160 stat. He does have the AC water pump pulley to speed things up a tad. It runs a very cool 170ish whether sitting or cruising.

[71 T/A]

Now that's impressive cooling. My car runs those temps too without the a/c on. Running a/c puts a heavier strain on these car's cooling system. My 72 Formula with a/c can handle it at idle with the air on. This car doesn't come close.

[66bonne]

71 T/A: I run the Meziere black pump. I agree with Stewart Components...it's the water flow [or lack of at idle] that is the problem.

Jim

[Formulajones]

Originally Posted by 71 T/A

Now that's impressive cooling. My car runs those temps too without the a/c on. Running a/c puts a heavier strain on these car's cooling system. My 72 Formula with a/c can handle it at idle with the air on. This car doesn't come close.

That's something to look at. You have 2 cars with AC and one runs cool while the other doesn't.

[Hooter]

I tried running the Meziere 42 gpm electric on my 565 that I just got going. Temps were cool at idle but would creep up pretty quick at highway speeds. Called Meziere and they recommended either their remote 55 gpm pump or go back to the belt driven pump. Replaced with an Edelbrock pump I had sitting on the shelf and runs fine now. 8" crank pulley and 6" water pump pulley. Lesson learned - electric pumps can't keep up at prolonged highway rpm's.

[1969GTO]

Originally Posted by 71 T/A

My 69 GTO with Turbo 400 and stock converter has the original 400 with a small Comp 212/212, 440/440 cam. I have a fairly new Griffin radiator, stock water pump with clearanced good impeller, stock clutch fan with Hayden fan clutch, 3.08 gears, Qjet, stock distributor, 12 degrees initial, advance in by 2400.

When moving car will run 165-175. But stop at a light and the temps will soar until the car is moving. If I'm at a long drive through, temps will keep going past 210 until I shut the a/c off and then the temps will stop rising instantly. Then when the car starts moving, the temps start dropping again. Car does not leak water and I'm using a high flow 160 Robert Shaw thermostat. Even tried with no thermostat or just the body of one. No difference.

Would electric fans help? A new Flowkooler or Edelbrock water pump?

My stock set up 69 GTO