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slight overheat, power drop and bad combustion

hithere, i own a '95 volvo 940 turbo (b200ft i think) which has had so far only minor problems. yesterday though i happened to notice that from the exhaust came an unusual smell, like of something (plastic? rubber?) burning. then i noticed the temp gauge was a little bit on the hot side (usually no matter what, it stays right in the middle).

I noticed that the water level tends to diminuish in time (i need to refill it every month or so), which could be caused by many factors.

I might be wrong on this, but i also noticed a slight power drop.

So i'm trying to make all the pieces of the puzzle fit together. I think there's something wrong, but what? i'm afraid it might have something to do with the seals :(

TIA for any clue,

Valerio M

Reply to
Valerio M
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blown head gasket?

Reply to
Perry Noid

Blown head gasket and warped cylinder head most likely.

Reply to
James Sweet

James Sweet ha scritto:

thanks both for your answers. that's unfortunately my opinion too. and probably the worst scenario. is there a way of telling for sure before bringing the car to a mechanic?

cheers,

Valerio

Reply to
Valerio M

There are several ways to check for a head gasket. Start the engine cold with the pressure cap off the pressurized surge tank. Watch the coolant in the surge tank for signs of bubbling or "false boilling". If so then it may be a sign that combustion pressure is entering the system through a failed head gasket.

Pump up the cooling sytem pressure with a cooling system pressure tester pump. Hold it at 15psi for several hours. Keep pumping it up if the pressure drops. Pull the plugs in the mean time. After several hours holding pressure rotate the engine with the starter with the plugs out. Watch for coolant spewing out the spark plug ports as a sign of a leaking head gasket.

With the cooling system full, apply 120psi shop air to each of the combustion chambers, one at a time, thru the spark plug port. Make an adapter out of an old spark plug shell and run shop air to the port. Rotate the engine so that the valves for that cylinder are closed. Watch the coolant in the surge tank for bubbling. If the chamber holds the 120psi with no bubbling then chances are the head gasket is fine.

Reply to
Mr. V

Probably a failed head gasket.

You can check for contamination of the engine oil with antifreeze by spending $20 to have the oil analyzed. Personally I do this about once per year on our cars just to keep on eye on things. The $20 is well worth it, and I caught a failing intake manifold gasket on a GM V-6 at only 40k miles this way.

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is one of several places who can provide this service. They are the ones I use.

John

Reply to
John Horner

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