Engine pushing coolant out - Bubbling out air - Burning - Help !

Igofaster13

Member
Mar 9, 2006
168
3
19
San Diego
So my friends 90 LX 5.0 Auto is pushing and burning the coolant out. It seems to shoot out from the over flow at high RPM's. And at idle it is bubbling air out of the overflow tank. It seems to be burning it also but not sure because there has not been too much smoke out the exhaust. So I was thinking it was either a blown lower intake gasket, or a blown head gasket. other then that the car runs great when it has coolant in it, then it overheats when it has no coolant left (after about 1 hour of driving). We just removed the thermostat, and replaced the waterpump, and installed a new HD radiator. What else can I do :shrug:

Thanks
 
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How do you test for HC's?

I believe that a test chemical is added to a sample of the radiator fluid.

Do a compression test first, a blown head gasket is definitely the top suspect.

Only use a compression tester with a screw in adapter for the spark plug hole. The other type leaks too much to get an accurate reading. Your local auto parts store may have a compression tester to rent or loan. If you do mechanic work on your own car on a regular basis, it would be a good tool to add to your collection.

With the engine warmed up, remove all spark plugs and prop the throttle wide open, crank the engine until it the gage reading stops increasing. On a cold engine, it will be hard to tell what's good & what's not. Some of the recent posts have numbers ranging from 140-170 psi. If the compression is low, squirt some oil in the cylinder and do it again – if it comes up, the rings are worn. There should be no more than 10% difference between cylinders. Use a blow down leak test (puts compressed air inside cylinders) on cylinders that have more than 10% difference.

I generally use a big screwdriver handle stuck in the TB between the butterfly and the TB to prop the throttle open. The plastic is soft enough that it won't damage anything and won't get sucked down the intake either.

A battery charger (not the trickle type) is a good thing to have if you haven't driven the car lately or if you have any doubts about the battery's health. Connect it up while you are cranking the engine and it will help keep the starter cranking at a consistent speed from the first cylinder tested to the last cylinder.

See the link in my sig to build and use your own blow down compression tester.