[alanmay0]

180 must be nice

[LPete]

Your gauge said 225, you shut the engine off, still with the radiator cap off, and it didn’t blow coolant all over? 50/50 antifreeze/water boils at about 223, and I’d think it would have instantly boiled over if it was really that hot.

If your elevation is higher the boiling point will be lower. At 5000 ft our boiling point is 10 degrees or so lower.

[Mr_GTO]

Water pump have a cast impeller? All the correct plates are with the water pump? There is a great thread in the Cooling Section of this page. Have you read through those replies?

[alanmay0]

I'm not using the cast iron water pump. I do have the two plates and they are installed correctly. I can't seem to find much when I search "cooling problems". thanks

[PunchT37]

Well, did you bring your timing up to 12?


Did you check your head bolts?


These things might not fix it but they don`t cost money.

[alanmay0]

Yes I did check the torque on all head bolts. I did move timing. I did a compression check on all cylinders all 145-150. Did the test for exhaust gasses in the radiator, could not turn blue stuff yellow. Water flowing good. Seems like too much heat in water for radiator and fans to remove any of it. Temp at thermostat housing and then at the spot where the lower radiator hose attaches to the water pump not much temp change at all. I'm stumped

[Mr_GTO]

Originally Posted by alanmay0

I'm not using the cast iron water pump. I do have the two plates and they are installed correctly. I can't seem to find much when I search "cooling problems". thanks

You're not looking hard enough then. There is an entire section on heating and cooling.
http://forums.maxperformanceinc.com/...d.php?t=411256

and I didn't mention cast iron water pump, I said cast iron impeller.

[darbikrash]

It’s pretty common to get air trapped in the coolant system when an engine is removed, overhauled and put back in service. Simply adding water while the engine is running with the radiator cap off does not always clear trapped air. In fact most of the time it doesn’t.

Air pockets can cause hot spots and impede coolant flow resulting in overheating.

The most reliable way to refill a newly overhauled engine is to “burp” it with a coolant filled container inserted into the open radiator cap. Fill the radiator as best you can (cold engine) and start the engine. Turn the heater on with the engine running and use a burp can to clear the cooling system of trapped air.

I use this one.

https://www.amazon.com/dp/B01A2CQSU6...n_0_title&th=1

[LPete]

It looks like you’re ready to pull the head off? I’d urge you to do a leakdown test before you do that. You’ll see bubbles in the coolant if the gasket is leaking (or the head is cracked). If you don’t see combustion gases in the coolant I doubt if it’s the head gasket. That’s a lot of work for nothing if it’s not the problem. What will you do if you get it apart and don’t see anything wrong? BTDT.

[Dynoking]

Originally Posted by alanmay0

So Should I use the seals or not. Has anyone else ran into similar problems with over heating and can anyone have any other suggestions for me to try.
alan

Those are not just rubber seals. The seals are supposed to be installed on tubes. If either (or both) the tubes or seals are not installed you will not have adequate coolant circulation and it will cause an overheating problem as you describe. Leaving the tubes and seals out are a common mistake with Pontiac engines.
Verify that they are in fact installed.

[tekuhn]

Without the seals, the water that is pushed into the block can leak around the plate and it just goes in circles inside the pump cavity. Absolutely install the seals and make sure the plates are seating firmly against them. Then make sure the plate is as close to the impellor as possible without rubbing.

The thermostat sets the minimum temperature and has nothing to do with maximum temp unless it's not opening properly.

[25stevem]

His 1968 and earlier timing cover/ pump set up does not use those tubes or seals that folks are posting about , so let's stop confusing the guy!

[Dynoking]

Originally Posted by 25stevem

His 1968 and earlier timing cover/ pump set up does not use those tubes or seals that folks are posting about , so let's stop confusing the guy!

Good point. Im not trying to be argumentative. His state's he has a '67 GTO. Has the actual year of the engine been verified? It is a 55 year old vehicle. Lord knows what these cars have been through. Just saying and thanks for your input.

[chemnick]

I have skimmed through the posts and will offer this to you. I was in a similar situation a few years back and I can feel your pain. I tried a lot of things, but for me, two things were what did it. First, with the engine-driven fan (7 blade) and proper shroud, I went from a heavy-duty fan clutch to a severe-duty fan clutch. Secondly, I installed all the radiator seals and installed the stock front-end sheet metal baffles that go under the front end of the car. It was as simple as that. The seals for the radiator and baffles for the front end were stock, I believe on all 1967 GTOs with AC and/or HO. I screwed around with a lot of things, but it came down to airflow through the radiator and fan speed. BTW, my radiator is a 2-row aluminum from Ames. GOOD LUCK with your situation. I'm just an old knuckle-buster and not an expert by any means. Just trying to offer a suggestion or two............................................... ........
Chemnick