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Cameo Ivory 1967
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maybe try a fan without the clutch. had a firebird that would heat up. i changed to a straight fan never had the problem again. but a new clutch on the fan should have fixed it. your stock fan should keep it cool.take a piece of paper put it in front of the radiator see if it pulls the paper toward the radiator. hope you get it fixed.
My flex fan got trashed and it was discontinued by Flexalight. During my research, I screwed up and ordered a 17" fan instead of an 18". It made no difference in cooling at all... still stays firm at 160 degrees. Im sure it save a few HP by shrinking the fan diameter... would be cool to test these things.
 

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Baaad65, we are close on specs so don't think your timing or compression can be part of the problem. My 462 with the 670 heads is 9.34:1 compression and timing is 14 initial, 38 total, and 12 degrees ported vacuum. Rear wheel horsepower is 451. Here's some areas that could be contributing to the low speed heat:

(Paragraphs removed since corrections were made below).

3. You didn't mention whether internal plates were hammered forward to tighten up the impeller/plate clearance. It's amazing how much coolant can bypass the impeller blades and just stay inside the pump.
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If your fine at average speeds and just low rpm slow speed issues it sounds like you need to speed up your water and air flow, I had custom pulleys made from Motor Mission Radiators in Vegas to get the most low rpm water flow I could for a Bronco, but I'm sure any machine shop could do it

I have the CVF serpentine set up on my GTO and it rarely creeps over 195 in extreme heat, gonna be 106 here today and if i leave it idling for about 20 minutes it will start to creep up to that 195 range normal driving and cruise nights pretty well parked at 185
I'll have to measure the pulley but CFV said it's slightly overdriven and looks to have good flow with the cap off, I run about 800 rpm at idle.
 

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The car runs cool at 160 170 while driving normal. At a light or slow traffic it bumps up quickly to 200-210. I used the infrared temp gauge at the top and bottom of the radiator as suggested. Readings were the same as the gauge. Radiator is aluminum with in and out on the same side. I installed a new 160 degree thermostat. New hoses and Evans cooling fluid. Timing is spot on. Water pump is stock. New fan clutch. Stock fan. I’d like it to stay around 170 180 when in slower traffic.
Not all fan clutches leave the manufacturer at spec. I've returned several after they failed to firm up as coolant temps increased. If a clutch is defective it can't be fixed. If it is good and coming in late, you can tweak the thermal spring since most end up increasing about 200° and slightly altering it can get it to come on 20° to 30° sooner.

I like stock cast iron water pumps. After testing and being around many of the trick and very trick aluminum pumps I've found that we can't tell any cooling difference solely from the type of pump. They don't do any harm, but not much good either. Just purchased the cheapest 8-bolt cast iron water pump Butler had on their page and it is now installed and doing a great job. The main point on this is the proper clearancing of the plate(s) to the water pump impeller. Nothing else makes as much difference is getting the plates nice and close to the impeller.

Many of our club guys have went with Champion radiators. The plant is close to us and the radiators can be ordered and picked up in a few days. and seem to actually work pretty good for the cheaper cost. If I had one I'd keep it, but my radiator of choice is the Cold Case.
 

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Baaad65, we are close on specs so don't think your timing or compression can be part of the problem. My 462 with the 670 heads is 9.34:1 compression and timing is 14 initial, 38 total, and 12 degrees ported vacuum. Rear wheel horsepower is 451. Here's some areas that could be contributing to the low speed heat:

(Paragraphs removed since corrections were made below).

3. You didn't mention whether internal plates were hammered forward to tighten up the impeller/plate clearance. It's amazing how much coolant can bypass the impeller blades and just stay inside the pump.
I gave up the mechanical fan because of to much drag on the belt causing it to screech, then I tightened it to much blowing out the bearings on the pump. I don't know anything about the plates as Butler assembled it and I never removed the timing cover, all I did when the pump went bad was replace the pump with the same one.
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1968 GTO 400, TH400
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I

I'll have to measure the pulley but CFV said it's slightly overdriven and looks to have good flow with the cap off, I run about 800 rpm at idle.
You can try letting it idle for 1/2 an hour at 800 rpm record the temps then try letting it idle at 1100 rpm for 1/2 an hour and see if it changes anything
I did that with the bronco the stock set up would hit 225 in about 10-15 minutes had the custom pulleys made and it can idle for over an hour and doesn't break 180 only difference were the pulley sizes
 

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I gave up the mechanical fan because of to much drag on the belt causing it to screech, then I tightened it to much blowing out the bearings on the pump. I don't know anything about the plates as Butler assembled it and I never removed the timing cover, all I did when the pump went bad was replace the pump with the same one. View attachment 154654
View attachment 154655
looks like your plate is too close at the ends, yo might want to reshape it some
 

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looks like your plate is too close at the ends, yo might want to reshape it some
The ends meaning by the outside holes, can you point it out on the picture and to close to what the pump?? The impeller left marks when the bearings let go. Like I said Butler set this up so I assumed it was done right, I just RRd the pump.
 

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You can try letting it idle for 1/2 an hour at 800 rpm record the temps then try letting it idle at 1100 rpm for 1/2 an hour and see if it changes anything
I did that with the bronco the stock set up would hit 225 in about 10-15 minutes had the custom pulleys made and it can idle for over an hour and doesn't break 180 only difference were the pulley sizes
Thanks, worth a try.
 

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I've ordered out quite a few pumps and plate combinations from Butler and have never seen them adjust the plates. Your Flowkooler pump will be pretty close out of the box but should still be checked. Basically the plate should touch or almost touch the plate with no gasket in place with the plate on the pump. Then the gasket thickness becomes the clearance from impeller to plate.
 

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I've ordered out quite a few pumps and plate combinations from Butler and have never seen them adjust the plates. Your Flowkooler pump will be pretty close out of the box but should still be checked. Basically the plate should touch or almost touch the plate with no gasket in place with the plate on the pump. Then the gasket thickness becomes the clearance from impeller to plate.
Thanks for the help....I couldn't tell you how close it was because I didn't take the plate off when I did the pump, didn't want take apart more than I had to and just assumed Butler checked all that. I can't remember if I tried the pump without the gasket to see if it rubbed either, but I really don't want to tear it apart again if I don't have to.
 

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With the Flowkooler you should be pretty close. I probably should put in a disclaimer while I'm at it that the Flowkooler impellers are usually pretty close out of the box, and the reason my cast iron pumps work good is that I take the time to hammer in the plate. If the cast iron was taken right out of the box I could see where it would come in a poor second to the expensive aluminum aftermarket pumps because of excessive plate clearance.

The bearing failing might not have anything to do with belt tension. Many years ago Cardone brought out their first new Pontiac water pump. I had three bearing failures in a row. Pump had a lifetime warranty but it was a pain to do the replacement and the last time the blades clipped the tubes and cost me a re-core of the desert cooler radiator. The Flowkooler might have been defective and it would have crashed with normal tension.
 

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Discussion Starter · #33 ·
Another senior moment …… I bought this car last November from a classic car dealer in Texas. It has an after market AC unit. I’ve been going through it little by little. I’m embarrassed to say I just noticed a cooler grill about the size of the radiator grill mounted 2” in front of the radiator. the AC grill has to be restricting air flow And causing the high heat at idle Without the AC running.
 

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That's the condenser for the AC unit. While it does contribute a very marginal restriction it really isn't that much. I added Vintage Air about 5 years ago and engine still runs at thermostat with the AC running, and definitely not a problem with the AC off. The new aftermarket units are so much more efficient than the original stock units and don't put near the load on the cooling system.
 

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This is my '67 GTO "Cruiser" that had the stock AC system. One of the changes I made was to install a Lexus 400 condenser to increase cooling capacity. While it didn't really increase AC cooling efficiency it also didn't hurt the cooling capacity for the engine coolant. Condenser was massive and basically occupied 100% of the opening.
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With the Flowkooler you should be pretty close. I probably should put in a disclaimer while I'm at it that the Flowkooler impellers are usually pretty close out of the box, and the reason my cast iron pumps work good is that I take the time to hammer in the plate. If the cast iron was taken right out of the box I could see where it would come in a poor second to the expensive aluminum aftermarket pumps because of excessive plate clearance.

The bearing failing might not have anything to do with belt tension. Many years ago Cardone brought out their first new Pontiac water pump. I had three bearing failures in a row. Pump had a lifetime warranty but it was a pain to do the replacement and the last time the blades clipped the tubes and cost me a re-core of the desert cooler radiator. The Flowkooler might have been defective and it would have crashed with normal tension.
I think mine did because I cranked it up so tight trying to get the squeal out, now I have a new RPM belt and adjusted it to be pretty loose when cold and it's perfect when hot.
 

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Still dealing with running hot here in SC. Looking for anyone that has success with electric cooling fans.
What brand and model number do you recommend?
Well, I think you bought a lemon with all the issues you have been having with that car.

In stop/go traffic where airflow is lower, engine temps will go up. 200-205 degrees is really OK. It seems to pull right back down once rolling. If it went more than 205 degrees, then I would be a little concerned. If you bring the RPM's up when it begins to get hot, ie push in the clutch and rev the engine up to 1,000 RPM's for a brief time, does it drop down? My '73 Fury owner manual tells to do exactly this when the water temps begin to get hot - put the car in neutral and raise the engine RPM's using the gas pedal.

BEFORE you start looking at it as a cooling issue.........

The 1965 GTO radiator comes in 2 sizes - the standard 15" high and 17.5" high for AC/Heavy Duty.

Supply us with several photos of the engine bay with the radiator/AC condensor for us to look at for review.

Give us the measurements of whatever radiator you now have in there. If too small, or wrong style, you may be wasting your money and time with electric fans. 3 & 4 cores does not mean it will cool better as depending on the maker, if the cores are too small in diameter or the spacing is too tight, the extra cores can actually cause a cooling problem as airflow can be reduced.

What is your idle speed in neutral?_

List your timing numbers:

What is your initial timing set at at the balancer - Vacuum advance hose disconnected and port plugged?____

What does your initial timing jump up to when you reconnect the Vacuum advance hose to the distributor?___

Revving up the engine - using a dial-back timing light OR a timing light and timing tape on the balancer, at what RPM does your balancer timing stop AND at what RPM?___
Example - 36 degrees on the balancer at 3,000 RPM's and the timing no longer moves.

What brand and number spark plug (heat range) do you use?___


DID you add all the rubber baffles required for a 1965 GTO with AC to direct the airflow through the radiator? Yes/No

Do you know what size jets are used in the center carb?_
What is your idle air/fuel ratio?_
Is your center carb running lean???__
 
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