Mechanics

GMC TRUCK GAS PROBLEM

1989 GMC Truck • 84,000 miles

I have a 89 chevy that keeps over heating. My coolant keeps dissapearing and I dont know where it is going. New thermostat and I have flusged the system. I am thinking head gasket but im not possitive. Any ideas?
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Dougdodge1500
March 19, 2013.




Have you checked to see if there is coolant mixing with the oil and the opposite?

Much more common on the GM V-8 engines is a leaking intake manifold gasket.
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Caradiodoc
Mar 19, 2013.
The oil has no coolant in it I alrdy checked that. Im pretty sure its the intake gasket. But I dont wanna tear into it and have it be somthing else. I fill the system with coolant a nd it all disappears. It isnt leaking on the ground.

Tiny
Dougdodge1500
Mar 19, 2013.
And is there any way to test to see if the gasket is bad?

Tiny
Dougdodge1500
Mar 19, 2013.
Pressure test may show it, but you can also add a small bottle of dark purple dye. The coolant may be evaporating as fast as it leaks out. After a few days, search with a black light. The dye will show up as a bright yellow stain that you can follow back to the source.

Caradiodoc
Mar 19, 2013.
Okay well thanks. But am I right is it a head gasket? Cause thats what everyones telling me. Thats the only thing I can think of. Cus it doesnt leak on the ground cus u dnt see it in the snow. And plus some eater comes out of the exhaust when it is running

Tiny
Dougdodge1500
Mar 20, 2013.
Sure it could be a leaking head gasket but that would be a lot less common. You may be able to verify that with a chemical test at the radiator. With the engine running, air is drawn through a glass cylinder with two chambers partially-filled with a special dark blue liquid. If combustion gases are present that liquid will turn bright yellow.

If you think coolant is going out the tail pipe, the dye will show up there too.

Caradiodoc
Mar 20, 2013.
Okay thank you for your help ill let you know what happens with it

Tiny
Dougdodge1500
Mar 20, 2013.

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