Northstar Engines and System Technical Discussion Discussion, Probly Not a New Question - Oil Pan Leak in Cadillac Engine Technical Discussion; We've lived with the burned oil smell, puddles in the
carport, and a quart or more of Mobil 1 every ...
We've lived with the burned oil smell, puddles in the
carport, and a quart or more of Mobil 1 every week
since we bought the car several years ago.
I do all my own work (have replaced the steering
rack, a real knuckle buster, and far too many
other fairly major and usually difficult repairs),
so can't see spending $1500 or whatever to fix
an oil leak that shouldn't be there to start with.
To avoid separating the transmission to replace
the rear seal, which I don't believe is leaking
at least not to a significant degree, is it possible
to drop the engine cradle and remove the crossover
exhaust to allow removal of the 2 pan parts?
I would imagine dropping the exhaust crossover
might be the tough one, esp. on the rear of the
I had to partially drop the rear of the cradle to
get at the rack, and don't see that fully removing
it would be that much more of a job.
Thanks to anybody that's gone thru this and
can offer some advice!
Thoroughly clean the engine area. If it is extra cruddy, use a high-pressure car wash to knock off the heavy stuff. I would then spray Westley's Bleche Wite Tire Cleaner on the bottom of the warm NOT HOT engine/transmission and any other areas that have an oil coating on them.
Westley's is a great tool for degreasing, it is non-flammable and nearly odorless.
Spray the large exhaust pipe leading from the engine to the catalytic converter and the bottom of the catalytic converter. This is likely where the oil burning smell is coming from. Oil is blown back on the main exhaust pipe and catalytic converter, which are both very hot.
Let sit a couple of minutes then using a garden hose with a spray head, rinse/blow off all of the area sprayed. This will give you a clean start to be sure where the leak is coming from.
Often the oil leak is not that bad, but is blown around as you drive making it hard to find the true leak source.
Tighten all of the oil pan bolts. Do not over tighten. The oil pan gasket is a silicone bead, over tightening will not help.
Tighten the front engine cover bolts, again no need to over tighten.
Check the oil filter for tightness.
Drive the car around for about 15-20 minutes avoiding going over 50 MPH.
Open the hood and check the oil cooler lines (2) at the right (passenger) side of the radiator. If there is any seepage tighten the lines. Caution do not over tighten them. If the lines were tight and still leaked, you need to unscrew them and replace the O-rings in each connection.
Check the oil cooler lines where they go into the oil filter adapter. If they are tight and still seep, they need to have the O-ring seals replaced.
I think Mobil 1 is a synthetic, these oils have a tendency to seep through small imperfections a regular oil won't. I would recommend using a conventional oil such as Pennzoil 10w-30w, or other major brand.
Hopefully your leak has been minimized with these few items.
Unfortunately, I've already scoped about all of that,
did tighten the pan bolts (most of them, couldn't
quite reach a couple) about 1/2 of a flat, that
helped reduce it by about 2/3rds.
I've repeatedly cleaned the bottom of the engine
(each time I change oil) and can readily see that
the seepage is coming from the pan joint.
I used to be Shop Foreman for a large paving
outfit & was in charge of taking care of over
$100 million of equipment of all types, so have
had all too much of that type of experience :-)
If I recall, the pan wouldn't be that tough to
get off (by the looks of it) if the exhaust was
out of the way. If that proves too difficult
at the rear of the engine, I might just try
using the stainless steel band type clamps
that join ends of pipe without slipping them
together, seal very tightly, are corrosion
proof, and reusable. That would allow me
to make a cut just behind the pan, take
the front connection apart, and relatively
easily get the pipe out of the way of the pan.
I had the same problem. Pulled the engine and replaced the oil pan seal, reinstalled the engine only to have a worse oil leak. In my case the oil pan AND oil manifold seals were bad. Ended up pulling the engine back out a week later to fix what I should have done the first time. In my opinion it's way easier to drop the cradle and pull the engine than to try and find a way around it. While I had mine out I went ahead and replaced every seal on the engine (peace of mind) including the rear main.
It won't do any good to cut the exhaust pipe. There is not enough room to drop the pan even with the exhaust pipe completely removed. The engine must be separated from the transaxle to remove the oil pan.
The oil pan has a silicone bead gasket; it presses an oil manifold that is sealed with silicone beads, to the bottom of the crankcase. If you are leaking a lot it is likely the oil manifold seal has failed and may need to be replaced.
Often the oil migrates down the bolt threads and seeps all over after that. I used a ¼” drive ratchet with extension with a 10 mm flexible socket, and was able to reach all of the pan bolts for tightening. It is a bit of a pain, but you could remove each of the oil pan bolts that are removable, a few at a time. Spray the holes and the bolts with spray brake cleaner to flush all traces of oil off of them. Then apply a thread sealant, or I have used plumbers pipe dope, and retighten the bolts. Allow to sit for 12 hours or so before starting the engine.
If this does not control the problem, I think you will need to remove the engine to properly fix the leak.