Shribe

iTrader: (1)

89 L98 devouring coolant, no milky oil, no puddles, no steam, no white smoke on start up. When I purchased it the factory temp gauge didn't work, an aftermarket gauge was previously added, along with new radiator. I have a strong suspicion it was overheated pretty bad a few times. The air dam was missing too. My only guess is the intake gasket which I read about. Any other ideas? Thanks.

Stekman

Coolant can't just evaporate in the engine. It obviously has to go somewhere. Whether it falls to the ground or into the chambers and comes out as white smoke. You say it doesn't puff at startup. How about when you go WOT?

NoTransistors

Do you have access to a Stant pressure tester? Pump it up. See if the needle goes down. Listen for leaks. Look for leaks. I like this gadget, because leaks are much more apparent when the engine is cold.
The heater core is delicate; don't pump it sky-high. Also, replace the radiator cap. A faulty one is hard to spot.
Further down the line, you can check for exhaust gas in the coolant. Kits are available. This would point to a bad head gasket, or crack in the block. No one wishes this on you. The intake gaskets are of poor design. They dry out and leak. The pressure test, when cold, may reveal this as a problem. We all hope that your problem is the least costly to fix.

transporter

Is the floor wet on the passenger side. Bad heater core maybe. Just a thought.

bobsroc

When the car is running, put your hand behind the tail pipe, do you feel or see moisture in the exhaust. If the car has overheated bad enough I would think head gasket or something warped possibly. With a gallon going away in 150 miles I would think it should be noticable somewhere. If the exhaust has no signs of coolant, check the cap. Your cooling system sould hold pressure after it warms up and the car is turned off. Try to squeeze the top radiator hose, it should feel full due to the 13-15 PSI of pressure in it and should stay that way while cooling off.

NoTransistors

I do not agree with Bob on one issue- Moisture in the exhaust. All engines have a seemingly damp exhaust. This will go away after warm-up, which eliminates the condensate in the crankcase. Let's not frighten 'Shribe' any more than necessary.

bobsroc

Sorry, not trying to frighten anyone. I guess I should have been more specific about the exhaust. The reason I said to check it was he indicated he wasn't seeing the fuild anywhere. It has to be going somewhere, the only explaination I can come up with is it is exiting thru the exhaust. Anywhere else and he should see or smell it. If it was the heater core, he would smell it in the car, if the cap was leaking, he should see coolant under the hood, at least see a signs of it on the fan, motor, etc. when it boils out, right?

NoTransistors

This is the reason I told Shribe to pump up the cooling system while cold. That Stant pressure tester is a wonderful tool. If he has a leak at the thermostat gasket, or radiator, or heater core, it might not be so visible. If he uses an alternative coolant, it probably has no smell. The needle on the pumps' guage is very revealing. If he then finds nothing, a test for exhaust in the coolant might be necessary. These all-iron Bowtie engines have to be terribly abused to crack a block, or blow a head gasket. My Triumph had an alloy head that would warp, and create a slight leak where the edge of the outer water jacket contacted the head gasket. You could see the wet edge of the gasket, but it would seal when hot, and there was never any exhaust gas mixing with the coolant, and there was no coolant in the oil. But, the engine would loose about 10-20 lbs. compression in one or two cylinders.
He needs to buy the Stant tool.

Shribe

iTrader: (1)

I did buy a new cap a few months ago. The heater core is not leaking. The Stant tool will be my next move. Thanks for the advice.

transporter

Isn't there some kinda dye that can put into the cooling system and then use a ultraviolet light or blacklight to check for leaks?

NoTransistors

There is for A.C. A similar kit for the coolant system would not find an internal leak. Waste of time.

Shribe

iTrader: (1)

(depression) It is the head gasket for sure. I had a mechanic check it while I was on vacation. I had read in a magazine about putting a different head gasket (from aluminum head corvette?) to raise the compression ratio. Or milling the heads. Should I do both those things or neither? Any adverse effects? I will be doing the head gasket myself, any tips?