B230F losing oil

Our constantly ignored but alway ticking 93 940 wagon is losing oil. I
don't even know how much. It's my younger son's drive. Yesterday I
asked hime to check oil. He had to add 2 qts. of Mobile 1 to top it
up. But I don't see smoke comes out of the exhaust nor oil stains in
the driveway. Where did it go?

 

Mobil 1 is synthetic, correct? I am not sure about 1993, but I am told
older cars have seals that were not made to handle the chemicals in
synthetic oil. This means they can deteriorate and cause leaks.

If you see no leaks, the oil may be getting burned. Have you checked
the spark plugs for carbon deposits? Do you see smoke from the exhaust?
It is also possible the rings are bad and causing oil to be burned.

Oil doesn't evaporate, so chances are it's getting burned. Look for
smoke.

 

If it gets burned, it does so in a slight way because as I said I don't
see smoke.

 

It is possible to burn oil and not see it. Try and get a rate of how
fast you are losing oil. If you don't see smoke then it's probably a
little at a time over time. Also, I am not sure what burning synthetic
oil would look like.

 

Check the condition of the rubber seal of the oil cap on top of the
valve cover.

 

My experience with cars that have catalytic converters is that the oil
burning has to be very high before smoke is seen; the converter will burn a
lot of oil smoke off - at least a quart per 1000 mile.

Mike

 

Sometimes a rear oil seal will fail, but only leak at highway
speeds. The oil may be scattered over the highway near your home.