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87 951 After thorough cleaning w/brakeclean of the oil filter housing(no leaks from filter) oil cooler lines and fittings(no leaks) PRV, Press. sending unit, Steering pump bracket, and the bracket? square in shape directly under PRV just under the oil pan gasket. Bracket? is bolted to the block 4 x 13mm bolts no leaks and a 5th bolt going to the steering pump bracket. After 10-15 minutes on idle, PRV no leak, sending unit no leak, oil filter and housing and oil cooler lines and fitting no leaks. The only place the oil leak starts to show is where the 2 brackets bolt together, coming from above? All bolts are tight. Unfortunately I didn't get a shot with the exact location of the oil but it collects on the little square shape on the left side of where the brackets mount pics. 1 + 2
Camshaft seal. You'll have to take the belt, gear housing off etc. to get at it.
It's difficult to follow the original post (ahem...), but I think he is referring to the little bracket that 4 of the lower balance shaft cover bolts pass through-- i.e., the bracket with the arrow pointing to it in the picture below. Right? If so, I'd say it's probably the lower balance shaft o-ring behind the carrier bracket, or less likely a cover-to-block leak or front seal leak. I'd probably start by doing the lower b/s o-ring and front seal, and it if still leaks, then remove the cover and reseal it to the block and do the rear seal as well while you're in there.
Yes, I think Tom’s right. The lower balance shaft seal is easy, as long as you can handle the belts. it’s simply a large o-ring between the balance shaft housing and the power steering bracket if I remember correctly. When I did mine, the dealer had pinched the o-ring and as it hardened it caused a leak. A reseal isn’t difficult. The balance shaft housing, as Tom the surgeon has demonstrated, is probably a little tougher.
Gees Tom, you are quite the resource on this board and I know have helped me. Thank you!
I also agree with Tom that the most likely culprit is the lower balance shaft O-ring, but there is also the possibility of the oil cooler/filter console gasket leaking. I just had a customer 924S where BOTH of these were leaking (944 NA has a different style oil cooler, but the housing gasket is the same).
You can 100% confirm this by removing the bracket shown by the arrow in Tom's photo, and temporarily install 4 shorter bolts to the lower balance shaft cover or shim up the existing ones with a stack of washers each. Then clean it up and run the engine while watching this area, and you'll be able to see if the oil is coming from above the balance shaft front cover or from it.
Tom/all, thanks for your input. As I said prior, this kind of work is well beyond my abilities so this job will be farmed out. Does anyone have a "ballpark" on estimated number of shop labor hours involved to replace lower Balance shaft o-ring seal and any "while your in there" items? I'd like to be as informed as possible when I get estimates. I had the belts, pump, rollers etc. relaced 2 yrs ago about 10k miles. I pulled the front covers and everything looks good with no signs of oil leaks/fluids if that matters. I am planning on using existing belts, etc. Until this leak gets addressed can anything terminal happen if I continue driving with the leak? I ask because I've had this leak for a couple of years and had the same leak on previous 951's without any issues. Have I just been Lucky?
I do get drops on the floor while idling or after a drive. It doesn't drip while sitting between use. It hasn't got any worse over the last 2-3 yrs. I do use about a Qt. of oil every thousand miles +/- depending on my driving habits. I know these cars use oil according to the owners manual but would you consider this excessive? On a side note I switched oil from Mobil 1 15w50 full synthetic to Driven HR1 15w50 petroleum and leak has slowed some and my overall oil press. has improved. Never drops below 3 bar on idle no matter how hard I drive it.
As long as it's not leaking onto the exhaust, it's more of a mess than anything. In my experience, synthetic oil leaks more than dino, and Mobil 1 is particularly good at escaping... I have a friend who uses about that much oil in his 50k mile '88. That seems like too much to me, but believe it's technically below what Porsche says is acceptable.
RonD, if you are losing a quart per 1,000 (even with a leak) then it’s pretty substantial. You’re engine doesn’t appear to be coated in oil, so I’m wondering whether you’re burning oil if the leaks don’t appear substantial.
I had an oil pan gasket leak which hit the exhaust and left puddles...and ended up changing that gasket, did a front end reseal (including the lower balance shaft reseal - which by the way was super easy). Even with all of this I wasn’t losing a quart per 1,000 - more like a quart per 3,000. After the work, my turbo uses about a 1/2 quart per 3,000 (that’s my oil change interval).
My recommendation would be to have the lower balance shaft resealed and while your mechanic is there have them look for other leaks especially at the oil cooler. It’s right there. Probably a $500 fix (I’m really guessing here).
If you choose not to repair the leak, I’d keep an eye on the belts to make sure there is no oil or coolant in that area...I would think that’s probably the greatest risk.
Good luck and it may be a very minor leak...just hard to tell without seeing it.
12-31-2020 | 02:37 AM
Possible Source(s) of oil leak
