Big oil leak, suddenly

[Felipe.Dos]

Stopped to get gas today and had a massive puddle of oil under me by the time i was done. No oil leaks before this but i just finished a looong road trip so i guess i blew a seal somewhere. Likely the rear main seal? or is there another seal or oil leak spot these engines are known for? Making a shop do the work and hoping i can save a little on diagnostics by pointing them in the right direction.

edit: its definitely the rear seal. i was just hoping there was some magical chance it wasnt :( so the new question is a) is there a guide somewhere for doing the rear main seal and/or b) anyone have a mechanic they recommend near Seattle?

[MarkH]

Double check that the oil pressure sender isn't leaking (while the engine is running). I've had these fail on a couple of other vehicles (1980's Camry and Tercel) and the oil almost sprays out of them making the leak look like it's coming from somewhere else once the engine is shut down.

[Felipe.Dos]

Hmm. I honestly don't even know where the pressure sender is on these. The leak definitely appeared to be near the bottom of the engine which is why I suspect the main seal. And it was really just pouring out - the dipstick shows basically empty now. If it could be just that it would be a huge weight off though....

[Burntboot]

That isnt typically how a rear main seal would fail, proper diagnosis is required

If given the choice, I would much rather change a pressure sender (15mins work) vs Rear main seal (5hrs+), just sayin'

[MarkH]

Hmm. I honestly don't even know where the pressure sender is on these. ..
I think it's under the oil filter (which could be another source of the leak). I'd add oil until there's a level on the dipstick, start the van and then have a good look underneath everywhere on all sides with a flashlight and see if you see dripping from anywhere.

[originalkwyjibo]

I had this happen on one of my vans. The culprit ended up being a plastic spacer under the mechanical fuel pump block-off plate/fuel filter mount. The plastic got brittle and a chunk fell out. They make black light dye that can be added to the oil to determine exactly where the oil is originating from although, I suspect with a leak as bad as you describe, it won't be difficult to find the source. Just fill it back up and crawl under while it is running. If it is the furl pump spacer, they make an aluminum replacemnt.

[Felipe.Dos]

Finally got back to look at the van, and its... not leaking any more? I'd put more oil in it, oil dipstick shows just under full. Ran it, drove it into the garage, jacked it up. Ran it some more. And I don't see any oil leaking - and after letting it cool down it still shows full? When it last leaked it looked like I'd taken the drain plug out, it was literally *pouring* out. Now nothing.

[originalkwyjibo]

I had the same issue. Jacking it up changes the angle of the oil in the pan as well as changing the way it drains from the areas it's being pumped to. Try jacking up both ends(with 4 jack stands of course) so it is sitting level then have someone rev the engine up and down. Deoending on the location of the leak it also may need to have the lateral g-forces of left and right turns to duplicate.

[originalkwyjibo]

One other thought. If the PCV system is plugged, the crankcase pressures will build and push vapors and oil out anywhere it can i.e., gaskets and seals. If that is the case, it may not happen until it has run for a while to build that pressure and may require the load and rpm of driving to duplicate.
I had this happen on an 89 Jetta I had years ago.