DML FAQ : Engine
: I seem to have lost a lot of oil, but can't find it. Where to start?
I seem to have lost a lot of oil, but can't find it. Where to start?
From my experience, it's possible to lose that much oil from a
badly, blown belly pan gasket. I lost quite a bit (kept bringing it back
it) from a partial (and I do mean partial), leaky belly pan gasket before
it sealed itself back up.
I would check the following (many have been already mentioned):
If you don't see anything by now, then it's probably time for pro. help
(if not experienced yourself). Sure hope not. I'm really hoping that
you'll stop at #2 above. Carry a couple of quarts (liters) of oil
around with you and drive judiciously (?) monitoring oil pressure, oil
level after adequate stop time and noting/trying to locate noises.
- Check the inside of your exhaust pipe/tip (once it's cooled down,
naturally). I would just use my finger and see if it's oily or how oily
it is. If quite oily, then it's probably coming through the
- Crawl under and see if there's oil coming from the oil filter. You
may have damaged it in your mud adventures.
- Pull the plugs looking for oily residue (write down condition of
each plug for future reference).
- Pull you air intake and see if the inside is oily.
- Pull the PCV valve and see if it rattles. If it does then it's
okay. If not, then cause may have been blowby.
- Pull the breather cap from the other side valve cover and note its
- Do a visual or vacuum test on the intake manifold. Haven't done it
for a couple years but it involves pulling the hose leading from the
PCV valve at the intake manifold, plug the hose, and re-attach to the
intake manifold. I put saran wrap over the intake manifold hose connector
and push the hose back on. Remove the breather filter on the other
side. Cover the breather hole something with something like a soft plastic
card (palm of hand could be used with care). Have someone start the
engine. In about a minute you should see card being held to hole by
itself or feel suction on your palm. This means that belly pan gasket is
okay. If there is no or little vacuum, then the gasket is probably
blown. Did you get any pinging on the way back when going up an upgrade and
putting a sudden load on the engine?
- If you have oil on any of the plugs, do a compression test on all
- If none of the above gives an indication of oil loss, pull the
valve covers and look for a broken/misaligned rocker, broken valve spring
or a suspected damaged pushrod. Oil for the upper parts come up through
the hollowed out pushrods.
Contributed by: Bob Tom
Last updated: Sun Oct 13 09:31:17 2002