Hi Folks,

We bought our 2005 MCS with 65k miles on it. I buy high mileage cars, and it was so nice to have something that didn't leak fluids! :D Well, now it has 160k. Had a leaking valve cover gasket, replaced that. I was disappointed to see it is still leaving little spots in the garage. I was under it while changing the oil and made these observations:
- Oil is all over the bottom of the engine, more concentrated toward the pass side.
- Not coming from very high, valve cover is not leaking any more.
- Hard to see in front of the engine due to the splash guard, but I don't think there is too much there. The back side is messier.
- MIGHT be originating near the oil filter?
- Maybe oil pan (ugh)
- Don't think it's the crank pulley seal.

What's a common leak point fitting this description on these cars?

Thanks! Jeremy

 

Anybody?

I learned from another thread that the oil filter housing /oil cooler is a common leak spot. Any other input? Thx!

 

I'm afraid you don't have a car known for keeping oil in

There are three spots that seem likely, I had all three on my car at some point.

1. Crank position sensor o-ring. This tends to slowly trickle down and get blown all over the bottom and back due to wind so it's hard to pinpoint. You probably won't see anything on the front. Is an extremely common failure so if you haven't changed this in ~30k, it's going to fail soon anyway so replacement is a good idea. Quite easy to get to by pulling the radiator housing forward.
2. Oil pan, like you said. Can verify by getting the engine super clean above, maybe add some masking tape or trace powder to indicate if it's coming from above.
3. Filter housing. You're correct on this, it's a moderately common one and is on the pass side, and a little hard to get to. If you can get a flashlight and a good view from the bottom you might see the path the oil took down. If you have oil above the oil pan on the rear of the engine, this is a very likely culprit.

 

In the front of the engine, there is a crank position sensor that always leaks. It is a cheap o-ring, but hard to replace, as it is behind everything on the front of the engine block. It spreads oil all over.
The oil filter area is another, but usually due to oil changes, as the filter is impossible to remove, without a big mess!

 

My crank pulley is currently leaking so you shouldn't rule it out.

 

+1 on the crank position sensor. Mine was leaking when I bought it and oil was everywhere on the front of the block and underneath. Seemingly impossible from such a small o-ring to produce that much sludge but just about every older Mini has this leak.

 

Suggest to the OP that he pull the bumper cover into the "Service Mode" in order to check the Crank Position Sensor and see what's going on, clean things up, etc.

 

There’s also an o-ring on the dipstick tube, which is on the passenger side. And I’ll comment that the oil pan gasket is not that hard to replace, if that’s what it turns out to be.

 

Thx y'all.

 

My dip stick broke and feel into the oil pan so I wound up redoing the gasket after all . This time I used no sealer ,just the gasket and carefully cleaned and followed the tightening sequence as per the manual and ..the damn thing is still leaking in the same spot .. I got so pissed off I used jw weld quick cure oil resistant stuff to seal up where the leak is . No more leak ....

 

Mine leaked for the 1st time the other day after I got it back from having the ps pump taken care of..but I wiped all down under the car and found its only the oil drain plug . I didn't replace the seal last oil change and now 5k into the oil it finally leaks a drop or two over night . But as I drive it makes it look like something major underneath as the wind blows it all over and makes it hard to determine the origin. Plus as it leaks it runs until it finally find the lowest spot which alot of times isn't near the leak and then drips there.

 

You need to clean it well and get it up on a lift or jack stands and run it while you look with a flash light . Alot of places for oil to leak

 

UPDATE:

I replaced the oil cooler gaskets / o-rings some months back, confident that was the source of the leak. Well, it was the source of A leak, not THE leak. Having that and the VC gaskets replaced, I was disappointed to still find oil spotting the garage and messing the engine. I decided I would replace the oil pan gasket, and the crank pos o-ring since I have the car in service mode. I did a big de-greasing, and just a day or two later I could see oil film forming at the back edge (lower point) of the oil pan gasket, so that's where the biggest part of it is coming from now. The crank pos o-ring is not that old, but it's a little messy up there as well so a new one of those is going in.

Maybe when this part is done, it won't leak oil again...for a while.

Jeremy

 

Everyplace there's a gasket is a leak point on these cars...
Oil Filter o-rings
Oil Cooler gaskets
Oil Pan
Valve Cover
Main Seal
Cam Sensor
Crank Sensor
Oil Dip Stick
Power Steering Lines
I'm sure I've missed a few