Overheating

Good morning,

How did you check the head gasket?

https://www.2carpros.com/articles/head-gasket-blown-test

Roy

Used a combustion tester and the liquid stayed blue.

Okay, I would do another test.

I would do a leak down test. that is where you insert shop air into each cylinder one at a time and look for coolant movement in the radiator.

Chemical testing is not always accurate.

Roy

Can you remove the radiator cap when the engine is cool, then start it up to see if tiny air bubbles are present? Also do you hear the cooling fan com on when the engine is overheating?

This guide can help:

https://www.2carpros.com/articles/engine-overheating-or-running-hot

Please run down this guide and report back.

Checked cooling fans. The are running when the engine overheats - I checked this by getting out and listening or looking. Both fans will stay on when idling until the temperature gauge
goes down to normal then shut off - although sometimes the temperature will not go back down and the engine has to be shut off after idling for a while. The fans also stay on at high speed for five or ten minutes after shutting down the overheating engine. Cold air can be felt blowing.

Today I got a combustion block tester. I took the car for a drive and brought the temp up to normal. Used the tester at idle - fluid remained blue. Put the parking brake on and transmission in drive to bring the temp up above normal - fluid remained blue. When I shut down, the reservoir burped out hot fluid three or four times.

There is no residue on the oil filler cap or the reservoir cap.

With the engine at warm idle, there are no bubbles in the coolant reservoir as seen in your video. However, I do get burps of fluid when the reservoir is over full and the cap is off. I can squeeze the top rad hose easily and it feels like there are pebbles running thru it.

The engine runs smoothly with not even an occasional miss at a stop light. Purrs like a kitten at any speed and accelerates like a big-assed bird when I floor it - no hesitation.

Driving around town the temp will stay normal for a long but will eventually overheat if I drive long enough. Climbing hills brings the temperature up quickly.

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I would still do the leak down test to confirm. I have never had good success with the chemical testing.

Roy

I do not have a shop or air.

Will take car to GM I guess.

You can take it any shop and they can perform the proper testing for half the cost of a dealer.

Roy

Oops, I forgot, it was done previously by a shop along with a coolant system pressure test - no leaks.

When was it done? What test did he do?

Has it overheated since you had this test?

Roy

Has overheated before tests and every day since all these tests in the last ten days.

Mechanic did a fluid test (which I did again with no yellow), pressure tested the coolant system - no leaks. Pulled plugs and bore-scoped for coolant - none, added shop air with no air bubbles into coolant. Mechanic very frustrated that he can't solve problem.

Okay, nobody has done the leak down test. It needs to be done. With the constant overheating, most likely you have damaged head gaskets.

Roy

To confirm the fans do come on? Also, I have seen a blown head gasket even though the chemical test does not pick it up. A chemical test is only about 75% accurate. Radiator, fan, water pump. if all are good it only leaves the head gasket.

I keep thinking head gasket too but there just is no evidence.

Top coolant hose is hard but maybe the implore is slipping on the water pump once the system is pressurized, thus the flow is not enough.

It's a mystery so off to GM - the same folks who put in a new gauge cluster last week when no one else could.

Please let us know what they find.

I've heard aluminum heads disintegrate after a while due to steel contact, forget the term. Maybe?

Will advise. Thanks for your help.

They get damaged for electrolosis. That is voltage in the cooling system from a bad ground somewhere.

Roy

If I need the heads replaced, who do you recommend for remanufactured heads? I'm in the Seattle area.

There are many manufacturers. Jasper, ATK, REcon are among the most popular with good warranties.

Roy

Went surfing looking for other solutions. Found www.thermalweld.com.

Spoke to Robert who says his product will fix my problem. Have you had any experience with them?

There is no such thing as an additive for repairing head gasket failure.

All it does is clog up the radiator and the heater core. These guys try to sell anything and do not care that it does not work and it causes more repairs. They got their money out of you and that all that matters to them.

Roy

Robert explained the gumming up is due to the reaction of the chemical and antifreeze. They tell you to replace the antifreeze with water, do the chemical and let it work, then replace the water with antifreeze. Also comes with a bypass that is cut into the top rad hose Sounded believable.

I would do the job and report back to you.

Not interested. Will never convince me. There is no sealer that seals compression pressure.

Their method is different. Don't idle after installation, drive at 60 MPH for five minutes which puts pressure on the chemical. I'm skeptical like you. It costs $250.00 plus shipping. These guys are going to send it to me for free. I only pay if it works. I'm going to do a careful install and analysis and report back. Shall I copy you?

Sure.

Good luck.

Roy

I posted my excellent results with Thermalweld head gasket sealer on Sunday but it is not up. Did you receive it?

No, I did not.

Roy

I live in a condo at the top of a small mountain. Half way home, my temperature gauge would redline and bells would scream at me. My previous posts detail what I did to try and solve the overheating problem - to no avail. It was the head gaskets and I was quoted $4,000.00 to $5,000.00 to replace them.

I found a website on the internet that said their chemical would repair my head gasket. One always wonders if these type of claims are true, but I tried it because the alternative was spending $4,000.00 to $5,000.00.

I want to be perfectly clear on what I did and the result. I followed the supplier's directions and flushed the coolant system with fresh water until I was positive there was no DexCool antifreeze left in the system - the antifreeze reacts unfavorably with their chemical. My engine is a Northstar 4.6L V8 which required a mod to the coolant return line that came with the kit. I was told to add the chemical two small bottles and then drive on the freeway for ten miles keeping my RPM's between 3,000 and 4,000. That wasn't necessary!

The head gasket sealed before I even got to the freeway! Wow! I did what I was told anyway. I have now driven 300 miles at highway speed (it overheated before) and climbed my mountain a dozen times. The temperature gauge needle stays in the middle. I have now flushed the system again to get rid of any excess chemical and replaced it with distilled water and 12 ounces of "Water Wetter". I'll re-install the antifreeze before winter sets in but will not use DexCool (orange color) as its cleaning action will eat the repair (and probably ate the head gaskets). Use a green antifreeze.

All these instructions are available on the supplier's website and included with the product. Plus you can call them anytime. they are very helpful with fantastic customer service. Here's the website: www.thermalweld.com. Use it. It's fantastic! It works in any car.

I hope it works for you. You will see in the long run.

Roy