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

 

blown head gasket?

 

Blown head gasket and warped cylinder head most likely.

 

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

 

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.

 

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.

www.blackstone-labs.com is one of several places who can provide this
service. They are the ones I use.


John