Let me start out by mentioning that I have tried a decent bit at chasing this oil leak. I know that probably will be a hollow promise to some of you, and I have not tried everything given that I have not replaced every seal on the car, but I have done the convinient ones without doing a full engine rebuild.

Now any of you that have seen my previous thread would know that this car is a $500 dollar 944 turbo. It has been in a field for 10 years and in a storage unit for 10 more before that. I guess I did get about what $500 dollars worth of porsche would get you and it is a big undertaking. I have been restoring it all summer and this is more or less the final issue I am chasing. Now on to the oil leak.

I have been chasing an oil leak that drips down on to the crossover pipe and burns enough oil to make the equivalent of a smoke machine in my garage. I have replaced the Cam Tower Gasket, the front camshaft O ring, the rear camshaft cork gasket, the camshaft oil seal, and a few other small seals on the front bit that pulls out of the camshaft housing and makes up the back part of the cover for the cam gear. I also have replaced the Cam Tower bolts because the old ones were so gone that I could not torque to spec without stripping them. Things I have not tried: head gasket, balance shaft seals, rear main seal, oil pan gasket.

Now for my reasoning for not trying the above mentioned. The top balance shaft is dry as a bone on the outside, both when I have had the intake off and looking through with the intake on, it remains dry. The lower balance shaft oil leaks, per members of this forum on other posts, seems to only leak on to the crossover pipe when at speed, such that the wind can push the leaking oil back to the crossover pipe. Oil pan gasket is one of the ones I've pondered quite a bit, but I assume this gasket has nothing to do with the pressure side of the system, and given the issue only appears when the engine is started and has run for about 15-30 seconds, I see this as more of a high pressure issue. I have not done the head gasket because it is very tedious to do and I did not see oil coming from this portion of the engine. Anything leaking down the back appeared to be from the Cam Tower, which is why I replaced all of the Cam Tower gaskets and seals. Finally, the dreaded Rear Main. I am really hoping there is some other seal I have forgotten that could be easier to replace and not as time consuming of a swap. Its quite clear why I would not want to do the rear main, but if this thread comes to the conclusion that it needs done then I shall do it. When inspecting, I thought the oil was coming from above and running down the bell housing, but maybe this was a misdiagnosis and the bulk of the leak was from the RMS. If I go in and do the seal, I may as well factor in the "while I'm in there" clause of car repair and do the aging clutch. This is a costly endeavor and my 19 year old's summer job may not support this before I head back to college.

At this point, I am just asking for any possible ideas as to what it could be. To prove I am not trying to just be lazy, below this I will make a list of threads I have used in my diagnosis and links to them. Thank you all for any help in my journey to bring this dying Porsche back to health

https://rennlist.com/forums/944-turb...t-drip-on.html
https://rennlist.com/forums/944-turb...-guidance.html
https://rennlist.com/forums/944-turb...-oil-leak.html
https://rennlist.com/forums/924-931-...crossover.html
https://rennlist.com/forums/924-931-...-included.html
My oil leak running down the engine looked very similar to this one^^

 

Not to be discouraging... But getting a $500 951 (that has been sitting for many years) back to life on a "19-year-olds summer job" before you go back to college (presumably shortly)? Let's just say it better be a heck of a summer job. That offers you plenty of free time. Not needing sleep would also free up some of the time you need.

Not that that's out of the way... Make it a summer project over the next year or two. You'll find lots of people willing to help out.

If you don't want to tackle the rear main seal yet... Try the Air Oil Separator seals. They are the source of a lot of leaks and are a lot easier to get to than the rear main. Still not "easy" to get to. Ultimately, these are old seals. You should plan on doing all of them unless you want to chase leaks forever. Cam tower. Balance shaft seals. Rear main. Oil pan gasket. The works. It's a lot of work.

For a bit of reference... if it is the rear main... the clutch and flywheel need to come off. After you remove the transaxle. At that point you might as well remove the torque tube and check it out (instead of just sliding it back for a clutch job). Which means dropping the rear suspension. It's a 20-24 hour job on a turbo. New clutch, pressure plate and throw-out bearing is $600-700. You should think about changing the clutch fork while you are in there. Another $300. And the pilot bearing (that's only $10-20!). Budget a couple hundred for a good set of tools if you don't have them already. And _good_ stands. And a floor jack. Impact wrenches are (really) handy but not essential. Torque wrenches...

 

Agree with above. Kudos from you for taking on this project.. but a word of caution.. seals/ gaskets all have a life expectancy.. sitting in a field reduces it considerably.. bite the bullet yank that engine out and refresh ALL the gaskets.. otherwise you will chase it for years to come.. once and done as opposed to constantly having your driving fun interrupted by leaks/ bad connections and when things DO break you will be so happy you can remove a bolt that is an absolute pain to get to… you know it will not be sized or break off in the block where you can’t get a drill… Food for thought..

 

Thank you both for the suggestions! I think I will do the AOS seals because I feel more comfortable taking the turbo out than I do the whole transmission. It's not looking good for finishing before college, I leave in 10 days, but that's okay. I have so far done all of the vacuum system, the fuel pump, tires, new AFM, and the gaskets mentioned above, oh, and a new starter. I also have done a full paint restoration to the best of my ability. It hasn't been too bad, I have been inhibited by that Ace Hardware salary though! I will however say that I may have in edge in that my career is *hopefully* mechanical engineering, so maybe that counts for something! As for the car, the price may be helped by me knowing the gentleman that sold it to me. Neither I nor he could stand to see it sit any longer. This winter I plan on pulling the engine and doing it all. In the mean time, AOS seems like a good plan though. Again, thank you both so much.

 

One fun thing you will find when taking this apart and really “ seeing” things how the engineers designed it will hopefully inspire you along your mech engineering path. When I first took my first car apart I was impressed how everything “ has a purpose” and in some cases a dual purpose or triple purpose such as the motor mount acting as the turbo pedestal/ oil galley/motor holder.. I always thought how cool is that? That’s how you stuff 10lbs in a 5 lb bag..

 

I'm going to go with GPA951 on yanking the engine if it's feasible. Some context...

I bought my 951 a little over 2 years ago. At that time... I had never changed my own oil. Since that time... I've replaced every seal, belt and hose, the rod bearings, done the clutch and torque tube, changed the head gasket, had the head and turbo rebuilt, gutted and rebuilt the interior, replaced bearings, rebuilt my Koni struts with a "chop a strut" kit... and much more. I took everything out of the engine bay except for the block in the process. I've learned a lot.

One of the things I learned is that a lot of that work would have been a heck of a lot easier if I had just bitten the bullet and yanked out the engine to begin with.

Good luck, have fun, learn some stuff and hope to see some stories here as you go...

 

Thank you @Millermatic i appreciate it a lot. I will start prepping for engine removal. The only reason I haven’t seriously considered it is I don’t have an engine hoist (yet). That’ll give me a chance to replace all of the other gaskets, do rod bearings, and water pump as well. Can I take the engine out without removing the torque tube and transaxle?
Best,
Cam

 

My bet is that the oil is coming from the rear plug on the lower balance shaft cover, the entire balance shaft cover, or the oil pan gasket behind the bellhousing. When I did my clutch oil was leaking on the gasket that is below the rear main seal. The oil would flow down the rear of the pan and drip off the rear bolts onto the crossover pipe. How wet is your oil pan?

On a personal note dropping the transmission is MUCH easier than removing the turbo/AOS seals. And if/when you do remove the turbo buy the Rennbay exhaust hardware set . You're going to break a lot of bolts.

 

Yes. Although I haven’t done it personally.

If you haven’t already, track down a pdf copy of the 944 and Turbo shop manuals (separate books)... you’ll need both, as the turbo manual doesn’t cover all the things that are common to both models. Hard copies are even better... but hard to find (and expensive). The 944 parts “Katalog” is also incredibly helpful. The illustrations are excellent - and are a valuable compliment to the grainy scanned pictures on the pdf copies of the Shop Manual. All of these can be found via Google.

Pelican Parts has very helpful tutorials (with good pictures) for all sorts of tasks. Clark’s Garage is the “grandfather” 944 site for how to do... everything... but is a little harder to use than Pelican’s guides (I think). And YouTube.

Lots of other good sites out there (in addition to this one).

And finally... the “Haynes” Guide is absolutely WORTHLESS. Except maybe for fire starter.

And “finally” finally... BilboSwaggins is right... it’s pretty easy to drop the transaxle. Admittedly a bit intimidating... but really not that hard. Getting it back in is a bit of a PITA.

 

This photo is the rear of the engine where oil is running down right along the mating point of the bell housing.

The mating of the bell housing right above the crossmember. Also caked with some oil

Here is caked on oil on the two bolts coming out of the bell housing

This photo shows oil pooling on the flange of the manifold/crossover pipe. It is running down the side of the manifold

This really shows the shininess on the bottom of that #4 header

This is just more of the manifold flange. Any darker or shinier spots are oil marks

A view of the other side of the header/manifold. It is wet on the outside

This is looking up towards the cam tower gasket area. I am pretty confused as I had thought that having replaced both the bolts and the gasket that it would not leak here but this is slightly contrary to that. You can also see oil puddled on the bottom of the #4 exhaust header

Another picture of that cam tower area. I changed the focus between pictures so I figured it might help

Here is the “oil cassette” as I have heard it called. It’s the thing with the oil filter and the oil pressure sender in it. When I tell you that sender is caked in oil I mean it is CAKED in oil.

This is some (I think) oil on the crossmemeber. I also did have a massive power steering leak so this could just be residual of that

Lower balance shaft housing. Looks to be some oil in the bottom back corner of it, but I think this might be drainage from higher on the engine

 

@BillboSwaggins I did not know the balance shaft has a rear plug,

I will investigate that. My pan is actually dry. There is caked on something, as if something was leaking in a past life before I had the car, but nothing that looks any sort of fresh.
Glad to hear dropping the trans isn't too bad. It is definitely one of the things that scares me, especially because I do not have a trans jack, just a normal low profile jack.

As for @Millermatic , thank you for all of the recommendations. The pelican writeups with the ultra high resolution pictures have been a godsend. Clarks garage has had its moments for me as well, notably with trying to fix the sunroof removal issues I have been having. I will have to pull those PDFs from the internet here soon. And those Katalogs have helped me find many parts including the turbo aux water pump which was the source of my first (and most major) coolant leak.

Since you both have been so helpful so far I will continue to pester you guys a bit.

I have attached the best pictures of the leaks that I could take given the tight quarters and low lighting. Do you guys think that cam tower is still the issue? I feel as if it is, but given that I have already replaced the bolts and also the gasket, I am not sure why it still would be leaking. I have heard the surface could be warped, but it looked fine upon visual inspection and looks to be a clean mate all the way along. I could have possibly put the gasket on backwards and covered the high pressure oil feed hole on the back side of the block, but I remember watching youtuber Casey Putsch replace his cam tower gasket and mention that orientation issue, and I could've sworn I remember carefully checking the gasket orientation on install. If I need I will pull the cam tower again and check, but at that point I should probably replace the gasket again right? Aren't those a one time use thing? If so I will order the Lindsey metal/rubber reusable one and hope. (this gasket: https://www.lindseyracing.com/LR/Por...99-03-RCS.html)

The last possible issue with it is the tight quarters on installing the bolts led to the bottom left corner (when looking at the Porsche script on the block) led to it stripping. I did a two phase torqueing with 10 ft-lbs and then 15, and that corner bolt made it to 10 and then somewhere halfway between that and 15. Could this small amount of not-torquedness lead to the leak.

Thank you both for everything. I need to start responding to threads to balance out the amazing amount of input you have given me!
Best,
Cam

 

"especially because I do not have a trans jack, just a normal low profile jack."

- You can get an adapter to fit on the end. They are a bit fiddly... but they tilt - which is helpful when removing the transaxle. I hacked mine together instead of buying a dedicated one.

Regarding the torque... I think it's a bit of an art for things with large surface areas. For the oil pan gasket there's a very specific sequence (I know that's not what you are talking about). After you finish "finger tightening" all of the bolts (20 or so!!) you'll find the first ones are no longer "finger tight" and you do it all over again. Same deal when you tighten them to 6ftlbs the first go around. The first ones you do will be loose by the time you finish the sequence. I cracked my oil pan with 10ftlbs. Fortunately I had another. That said... it sounds like you stripped a screw. Or worse... the hole. By the time you are done with all of this... I expect you will have seen lots of discussions about "time serts" and other methods to fix stripped holes.

But probably more importantly... To answer the question "is "X" leaking" (the "X" being anything)... the answer is probably "yes." It's all leaking. From the pictures, I'll guess the AOS and the rear balance shaft seal (an o-ring). Maybe the o-ring at the oil pipe going to the turbo where it's fed from the balance shaft housing. I imagine every o-ring in your car is squashed.

I'll be happy to go through the rest of your questions... but it will have to wait until tonight... I'm a bit booked today. I owe the people on Rennlist a lot... so I'm happy to return the favor if I can.

I will offer up a "before and after" for my personal project. Hopefully it will be encouraging. The photos represent about 2 and a half years of work. The lower left is from when I bought the car. The lower right was last fall on it's way to have a mechanic check over my work. Since that time... I've had the transaxle rebuilt, replaced the clutch and rebuilt the TT (there's a thread on that here somewhere). It's almost back on the road.

Looking at the images below... I'm reminded to offer a final bit of advice... Check the insulation on your engine harness. And BATTERY cables. Mine had long stretches of exposed cable. I'm lucky it didn't start a fire.

 

a ratchet that bends, a short 3/8 drive “ wobble” and a 3/8 6mm can get on tha pita bolt at the end straight…