Overheating

CAT5CANE

MEMBER
1998 CHEVROLET LUMINA

Engine Cooling problem 6 cyl Front Wheel Drive Automatic 160000 miles

car is overheating. But no leaks on ground. Temp fluctuates hot/ cold when driving, then it gets near red line. Sometimes Reservoir gets over filled and bubbles air. I suspect air blockage in engine or head gasket leak. Sometimes reservoir fluid will not release back into radiator. Maybe back pressure? Air pockets?

I followed book instructions opening bleeder ports when engine off and cold, fill radiator with fluid until fluid comes out of both ports, fill radiaror, then fill reservoir to cold line. Started engine, open radiator cap to check antifreeze level if full after starting. As the engine gets warm, fluid starts pushing out of radiator. WTF. If I have to wait for thermostat to open to see circulation, then I'm losing all of my fluid on the ground.

yesterday, drove car 2 miles, at first OK, then it jumped to 260. I tried to turn on AC, then tried heater, I could hear the fan on, but could not feel AC or heat air coming through dash vents. Shut off engine, let cool to drive back home.

Parts already replaced. Radiator, Thermostat, water pump and now. 16 lb radiator cap w/vent release.

What am I doing wrong, what could it be and how to fix it? What is the right procedure to remove air pockets?

Cat 5. Need help!

5 Replies

DOCFIXIT

MECHANIC
18,828 POSTS

Hello,

This sounds like to me you have a blown head gasket because these engine had that problem. To confirm the issue please follow this guide. Do the fans come on? also is the coolant flowing in the radiator you could have a water pump impeller problem.

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

Please run this test and get back to us.

Cheers

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Monday, July 5th, 2010 AT 2:13 PM

CAT5CANE

MEMBER
3 POSTS

Yes, they activate when engine is hot or heater and /or AC is turned on.

My question again. What is the proper way to assure removal of air from radiator and engine. Per the original book, it states the above when cold and not running.

One tech at a auto parts store said "to add fluid at reservoir" and leave radiator closed. But radiator has too munch pressure when engine on and will not let fluid flow from reservoir back to radiator. But If I start car and then loosen air ports. Hmmmm, maybe. It would work! Now, how do I add more fluid to engine with engine on? When do I open the air ports. When engine is cold, warm or hot, after thermostat opens?

OR

Start engine with all opening closed. Wait until engine gets hot and thermostat opens at 195. Then open air ports, then release pressured air from radiator cap using vent release, then remove radiator cap and add more fluid until fluid comes out of air ports and radiator, then close ports, then install rad cap.? Is that it? Or am I missing a step?

Guys. Look, I'm unemployed and down to one car without money to screw around, playing guessing games. If ya gotta an answer. Spill it out. And be exact with step by step. I'll send in donation when I get back to work!

Thanks for your help in advance!

A VET !

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Tuesday, July 6th, 2010 AT 9:15 AM

DOCFIXIT

MECHANIC
18,828 POSTS

Engine cold and off open bleed valve add coolant to RAD. Fill till coolant comes out valve and coolant full to neck RAD no air bubbles. Cap off RAD warm engine add coolant to reservoir full line. Shut engine off once at OP Temp. Allow to cool open RAD cap fill as needed top off reservoir. Did you check for the head gasket?

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Tuesday, July 6th, 2010 AT 10:06 AM

CAT5CANE

MEMBER
3 POSTS

Thank You DOC.

Drove the car for a 1/2 hour. Temp gauge was fluctuating and finally got hot and hotter. Turned off engine and let cool. Restarted and drove home. Found fluid leak at rear engine seal. Now everything makes sense. Leaking head gasket. Losing pressure, thermostat not opening, engine getting hot, air pockets. LOL.

Bought Bar's head gasket seal. $30.00 and did the steps again to fill radiator. Ran it in park for about 45 min. And so far no leaks and engine did not get beyond middle of temp gauge. Checked oil. Good.

Waiting for engine to cool to top off fluids and do a test run.

Thanks for the support, Doc.

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Tuesday, July 6th, 2010 AT 4:20 PM

DOCFIXIT