I have a 2001 Montero LTD with 3.5L V-6. Just completed rebuilding the engine, the whole thing, down to the last bolt. Fired it up yesterday and it kicked right over and ran. Oil light stayed on so I killed it and found all of my new oil on the garage floor.

It looked to be leaking from the area of the oil filter. Hard to tell 'cause oil was all over the lower passenger side of the engine. I removed the filter and it was dry, no oil in it at all. Removed the 3 bolts for the filter mount and the passages coming out of the oil pump were dry, no oil. With the oil level full for hours before kicking it over, it didn't leak a drop. I'm stumped . . . any ideas? what could drive the oil out of the running engine with nothing coming out of the oil pump to the filter??
Very much appreciate the help.

 

That one is hard to diagnose. You will need to invest in another 5qts of engine oil, top off the oil in the engine. Get a buddy (or wife or gf) to start the engine while you crawl under the passenger side with the flashlight. Once the engine is running, you should be able to see exactly where the oil is coming from.

 

You said complete rebuild. Did you leave out the o-ring on the oil pump housing?

See Post 77
https://mitsubishiforum.com/forum/mi...l-48920/page8/

 

thanks for the quick replies!
I thought about putting more oil in it and watching it. I'll give it a try. It's not a small leak. the entire 5 qts emptied out in about 30 seconds, has to be something big that I missed. Also, with no oil getting back to the filter or oil cooler, it has to be somewhere in the oil loop before it gets back to the oil pump. I put a new oil pump on when I rebuilt it. The engine has a lot of O-rings I can't specifically remember if I put one on the pump or not. thanks for the suggestions. Back to work!

 

You also need some kitty litter to put down under the engine when you do your test

 

All fixed and running like a charm. Funny . . . I removed the oil filter and took off the housing it's attached to. Inspected and verified the gasket to the oil pump was there and good. Did not find anything out of order at all.

Put back together with a new oil filter, filled 'er up and kicked it over. I was fully prepared to see where it was leaking. NO LEAK!. I don't know what caused it to spew all it's oil in 20 seconds, and then not leak at all. Only thing I can think of is maybe I had the the alternator wire(s) pinched under the oil filter the first time? tho it doesn't look close enough for that to have happened. Any way, good to go unless I drop all the oil going down the road some day. thanks for the assistance.