Oil Issues

[Jred42]

Hi,

So I have a 88 Turbo S that I bought a bit over a year ago. It has about 60K miles and it was a barn find, so the person I bought it from knew nothing of its service history. Also, since he was in the process of selling it to a dealer, I had to move quick to grab it up, so I didn't get the inspections that I should have had done. But, alas, it is now my car, and I'm in love with it despite its numerous problems.

The number one issue I've been fight has been oil leaks. It didn't leak when I got it, but due to the lack of history the first thing I did when I got it was a timing belt/water pump change. Per some suggestions, I also changed my front engine seals while I was in there. After re-assembling everything, I had major oil leaks. So I dug into the car yet again and gave the seals another shot. This proved ineffective. I believed a large part of my problem was that I was working under poor conditions (not my garage, rushing to get done, didn't have good visibility to what I was working on). So, I took the car to a shop that specializes in older Porsches (Munk's Garage in Waterford, MI). They did a complete inspection and replaced the seals for me. I've now got the leaks down to what I would consider and "aesthetic" level, but there is definitely still some oil coming out around the lower balance shaft area.

I've also developed another oil issue. It appears now that my turbo is leaking oil during high load. There is oil collecting in the IC lines and I get a strong burning oil smell any time I go WOT.

I have 2 theories on this.

The first is the turbo seal dried out while the car sat (the log in the owners manual show the car had 50K miles in 1993, it only had 58K when i bought it in 2012) the seal dried out and it just took a bit of driving to make it fail.

The second is that for some reason my oil pressure is too high. I've been concerned about this from day 1 since the pressure gauge always reads higher than I would expect. It is pegged at idle when I start and only drops to about 4 after a good 30+ mins of driving. Even then it is always pegged any time I'm above 2000 rpm. I was told on Rennlist that this is normal, even though it is completely different than my dad's 86 911. I run 20w-50 Valvoline VR1 per Rennlists advice. I feel like high oil pressure might also explain some of the issues I have with the front engine seals.

So my questions are:

1. Does my oil pressure sound like it is correct or maybe too high?

2. Does my turbo need a rebuild?

3. Is there some secret to getting these front engine seals to seal?

4. What oils are you guys running? (I'm sure this is a repost, a simple link to the appropriate thread will suffice.)

I would really like to get this car fixed and ready for some modifications. Money on parts and tools won't be an issue, but I'd like to do the work myself. I have my own garage space, so I won't be rushing the job this time.

Thank You in advanced.

[rick13]

These cars burn a lot of oil. Unless there is lots of blue smoke blowing out of the exhaust...I wouldn't worry. The front seals should be easy enough. Although..... the 2-piece housings DO need to be perfectly lined up.

After careful alignment, I used some light wet sand paper to make sure the surfaces were smooth and silky. Then I prelubed the seals with oil...NOT synthetic...then pressed the seals in. If your housings aren't aligned and sealed properly, that might be your problem.

[GorillaFoot]

My understanding is, if the J-boot going into the turbo is dry and the turbine is dry, but your intercooler hoses are wet with oil, then your turbo needs to be rebuilt.

You will notice that there is a hose coming from the Air Oil Separator to the J-boot. If you had blow-by from the pistons, then the AOS would fill up and deposit the oil in the j-boot, just before the turbo inlet.

I'm a big fan of VR-1. It substantially improve oil pressure, especially over Mobil 1, and has the ZDDP your engine needs. Trust me, you don't want low oil pressure and it sounds like your car is doing what it should. VR-1 is a racing oil without detergents, so you have to change it more often. If you want an oil with detergents and a lot of ZDDP, look into Joe Gibbs DT5.

Removing the turbo is a pain, but rebuilds are cheap and well worth it for the turbo response. If it's something in the engine, unless you have a spare $???? sitting around, find yourself a breather tank for the factory AOS...

[nize]

welcome to 951 ownership! it would be nice to see some photos of the car. most of your questions, including your oil questions, are answered here;

Porsche 951 (944 turbo) reference list

note the section that reads:
what's the best motor oil for the 951? oil with more than 1400ppm of zinc...

[zedsn]

I don't believe that you mentioned what kind of oil you are using but if it is synthetic you will be getting leaks that mineral oil wouldn't. Your oil pressure regulator could be stuck causing you the 4 bar oil pressure when the car has been run for awhile and at idle. A hot car should come down to 3 around bar or so. I had to pull my turbo because of the oil smell on WOT and sent it out for rebuild just to be on the safe side. I could have rebuilt it myself but for piece of mind because of the PITA job of removing and reinstall I slept better at night sending the turbo main section out for a rebuild. My 2 cents.

[333pg333]

You really can't have too much oil pressure based on the oil type/brand.

[guru944]

Jred42:

I would run an engine flush then drain that 20w-50 stuff out. ***Stick with 10w-30 Synthetic Mobil 1 or better.*** Use a high quality oil filter with both anti-drainback and bypass valves built in (OEM, Bosch or Purolator).
Check your vacuum with a gauge at idle (should read -18 to -17 hg) and under part throttle (Driving not needed).
How many miles does it have?

I have seen 2 different 150k Plus 951's that don't burn any oil. Very unusual indeed.

[guru944]

jred42:

Turbo is probably done! Rebuild or replacement will be needed. I would keep boost low until that is properly addressed as well.

Later...

[guru944]

jred42:

consider this????? Boost pressure going past turbo seals into oil system pushing oil past all your seals and Gaskets...

later...