OMG - Bad oil leak problem! Where's it coming from?

[RajinCajun]

Hi folks! 1997 Boxster, 2.5L. Standard issue, nothing aftermarket. 105K on the miles.

Two weekends ago, had a friend help me change out the rear main seal. Enough evidence to prove it was in fact leaking. No problems with the change out. Actually went a lot smoother than I expected and the entire job was finished in about 4.5 hours.

The following week, I notice oil on my carport floor. Crap! Start to investigate, and I find oil had pooled on top of the engine block, mostly on the right (passenger side) from the throttle body area forward. Lots of oil. Enough to fill the casting divets on top of the block and overflow to the sides of the block. Soaked it all up with some paper towels, cleaned as best I could with some brake parts cleaner. I also drained about a quart of oil thinking maybe there was too much in there. I had added some Lucas stop leak to slow the main seal leak temporarily until I could get to it. That was about a week before I changed the seal. I was thinking I had added too much and caused a little (some) oil to blow out??!! Obviously, I'm no mechanic or expert. The dip stick read about a 1/4 quart below max after I drained some.

Drove the car, and yes, lots of oil on top the block again. To add to the pain, my starter died. So, I pull the starter, and while I'm at it, I pull the housing between the two intakes, and loosen the passenger side intake. Didn't remove it, just loosen it so it could move a little for me to see around it.

I see nothing obvious that would cause a leak. Check all that was visible for tightness and for cracks, etc. Nothing obvious to me. So, what next? I have no idea where to start looking. Any help is greatly appreciated!

Thanks

Brian

Edited March 24, 2011 by RajinCajun

[BoxsterTaff]

Brian - I would check 3 things. The oil is on top of the block so the only ways I am aware of that it could get up there, are:

1) check the AOS J tube as is enters the throttle body, if the AOS has failed and is pumping oil and the J-tube seal is bad that would put oil on top of the block.

2) check the oil filler tube for leaks on the lower section, esp as it enters the block under and just fore of the air intake cross connect between plenums.

3) check the oil cooler to the driver side of the block under the air intake pipe that runs from the filert box to the throttle body for failure.

I'm just an amature, maybe some of the more experienced guys can help too?

[1schoir]

Hi folks! 1997 Boxster, 2.5L. Standard issue, nothing aftermarket. 105K on the miles.

Two weekends ago, had a friend help me change out the rear main seal. Enough evidence to prove it was in fact leaking. No problems with the change out. Actually went a lot smoother than I expected and the entire job was finished in about 4.5 hours.

The following week, I notice oil on my carport floor. Crap! Start to investigate, and I find oil had pooled on top of the engine block, mostly on the right (passenger side) from the throttle body area forward. Lots of oil. Enough to fill the casting divets on top of the block and overflow to the sides of the block. Soaked it all up with some paper towels, cleaned as best I could with some brake parts cleaner. I also drained about a quart of oil thinking maybe there was too much in there. I had added some Lucas stop leak to slow the main seal leak temporarily until I could get to it. That was about a week before I changed the seal. I was thinking I had added too much and caused a little (some) oil to blow out??!! Obviously, I'm no mechanic or expert. The dip stick read about a 1/4 quart below max after I drained some.

Drove the car, and yes, lots of oil on top the block again. To add to the pain, my starter died. So, I pull the starter, and while I'm at it, I pull the housing between the two intakes, and loosen the passenger side intake. Didn't remove it, just loosen it so it could move a little for me to see around it.

I see nothing obvious that would cause a leak. Check all that was visible for tightness and for cracks, etc. Nothing obvious to me. So, what next? I have no idea where to start looking. Any help is greatly appreciated!

Thanks

Brian

Brian:

Taff has covered most of the possible sources of oil that might end up on top of the block.

I would add the little o-ring that is at the base of the dipstick tube, and the larger o-ring that is at the base of the oil fill tube (where each one meets the block).

A good way to locate the source of the leak would be to clean the top of the engine again and monitor it at short intervals to see where it is originating.

Regards, Maurice.

[RajinCajun]

Taff / Maurice

Thanks gentlemen. I'll look at all you have suggested. After i posted the initial post, i went back out and did some more looking. The J tude and connections is fine. The filler hose also seems fine. Did not yet check the cooler. But, interestingly, I did find that the dipstick guide hose was cracked, almost all the way around. Tomorrow I will clean it all up, install the new starter, and let her run while i watch for the leak. Will let you know what i see. thanks again,