New 964 owner with an oil leak question

[RedCarr710]

Hey all,

I just made the leap and purchased a '91 964 at the beginning of July and am taking my time getting to know her. I still can't believe I have one of my own...I go out to the garage every morning just to look her over...

Anyway, I've been read every post in both 911 forums back to the beginning of June but still have a question for the experts. The car is a '91 964 with 78,000 and in very good exterior and interior condition. The engine was serviced back in Apr by the PO by a reputable shop and he spent a boatload to "reseal & tune engine" (oil seals, gaskets, o-ring, dist caps & rotors, belts - too much to list). The car runs very well but there is a slight oil leak, which the PO made me aware of before I purchased. He said that when the engine was tuned, the owner\mechanic said that there would be a slight leak due to a very small linear gap (I don't know a better term for it sorry) that remained at the bottom of the engine - according to the PO, the mechanic would have had to "break" the engine to remedy that gap which obviously was not in the best interests of anyone. So, the car does leak several drops after running and there is usually visible oil on the engine cover plate after I run it.

Here's my issue: I've checked the oil several times (after reading about the proper method) and it looks to my novice eyes that the oil is as much as 1/4 to 1/2 inch over the "top" level (twist) on the dipstick. From what I read, it's overfilled - though I may not have idled the car for quite long enough after driving (maybe 20 secs instead of 30 secs). Can anybody give a newbie some advice here? I'm wondering if some of the oil that has been pooling after the car has run (maybe a teaspoon here and there) is due to the PO's overfill?

Sorry for the long post but I appreciate the advice.

[lucittm]

I have the same year in a turbo model. The engines are a little different but the oil leakage works about the same. It is unlikely that your oil leak is caused my a minor over-fill. Occasionally, a massive over fill will cause some oil to carry over into the intake system where it pools in the air filter and then leaks onto the top of the engine but always finds the lowest point and drips from there.

I don't think you have that much extra oil from the description you gave. For an engine "reseal and tune" the engine cases would not normally be split. In my mind "reseal" would describe replacement of the valve cover gaskets, new oil return tube o-rings, new cam chain cover gaskets and associated o-rings, power steering pump to engine o-rings, several new copper sealing rings, crankshaft front and rear main seals, oil vent cover gasket, oil drain plug seals, and possibly case stud o-rings and head gaskets.

Split cases are for higher mileage engines that require new main or connecting rod bearings, intermediate shaft issues, or a broken oil pump (they hardly ever wear out). Check your receipts to see if the engine cases were split. If they were and a gasket surface was not covered by the sealant you will have a leak as you described where the case halves meet.

If the leak is somewhere else, it can be repaired but usually at great expense of time and dollars. I would say drive the car and learn to live with the oil leak unless it starts to get out of hand. If it was a case seam, I would actually try to clean the surface to the atomic level and then force a bit of sealant into the offending area. It won't take much but you really have to squeeze it through a small opening. You might try very slightly thinning the appropriate type of sealant with one of those chemicals that rots your brain cells like naptha, acetone, methyl ethyl ketone, or lacquer thinner. There are only a few sealants recommended for this application due to the heat, vibration, and case stretch under high temperatures. They are Loctite 574 or Dow Corning RTV 730. You might get lucky and find that the source of your oil leak is one of the case through bolts/studs. Some of the holes for these bolts/studs are oil galleries and carry lots of hot oil. The remedy is to replace the (probably pinched) o-rings on each end with new green viton o-rings.

Good Luck,
Mark

[RedCarr710]

Mark,

Thanks for the great info. The PO brought it into the shop due to a pretty significant oil leak and the following was done:

"reseal and tune engine: front pump seal, 2 housing to rocker oil seals, 1 camshaft gasket, 1 camshaft o-ring, 2 dist caps & rotors, plugs, air filter - R&R muffler, distributor, tin work, timing cover, camshaft gear, cat. converter, rear engine mounts, air cond bracket, clean corrosion from timing chain housing, install timing housing to camshaft housing gasket, at cam drive end install o-ring, seal timing chain housing (install seals, camshafts and rocker oilers - left and right sides, adjust valve and camshaft timing, adjust belts, torque cylinder heads. steam engine/paint rear tin. change spark plugs."

Nowhere on the invoice does it say the engine block was split - perhaps the mechanic just noticed that there would be a slight leak from the seam upon close inspection?

The engine looks immaculate from the top so I definitely don't have an overfill oil leak at the air filter. It's good to know that the relatively minor overfill isn't causing the smallish leak. I definitely want to avoid the "slippery slope" of expensive diagnostics/repairs so a teaspoon or two of oil every week or so isn't a big deal to me. This helps put my mind at ease and just enjoy the ride..which is just plain freakin awesome.

Thanks again for the help.

[911jettat]

Redcarr,
Welcome, and congrats on buying a 964...they are amazing cars!

I love this forum, but some groups on Pelican are stronger than others and the 964 section isn't the most heavily traveled. You might get a better response to your questions in the 964 forum over at rennlist.com. When you visit Rennlist, do a search under "oil level" and "reading gauge levels". You may have to use a Turkey baster to get the excess oil out.

Again, welcome!
Udo - 911Jetta

[RedCarr710]

For those experts who have been following this thread:

I spent some time under the car today and saw that there were some drops of oil hanging under the engine area next to the opening in the engine tray (tray currently installed). This appears to be the source of the slight oil leak. I'm still not sure if I should take action to reduce the oil level in the car - right now the oil looks to be high (at or slightly above the upper mark on dipstick). Is there an easy way to remove some oil without emptying from the crankcase or the thermostat plugs? (not sure I am quite ready to start wrenching on the plugs...) One poster mentioned a turkey baster in the oil filler to take out some oil- is this a serious and recommended approach? Sounds like the oil level is recommended to be midway at the most on the dipstick...

One other issue is that I have a slight power steering (red) fluid leak coming from the center of the car, probably about 6' - 12" forward of the rear wheels. I'm sure this is just the lowest point where it is collecting (? - or some seal or another?) - I've checked the reservoir and the fluid is currently within the min-max range cold. It looks like one of the lines coming from the rez looks a little greasy around the hose clamp - I've read that these clamps sometimes need to be replaced. Should I check the engine for leaks when running? I haven't taken the car out in 5 days or so as I'm waiting on getting two new tires on Monday before I put many more miles on it.

Should I have my shop diagnose the power steering leak and recommend a fix or should I monitor it for a bit - looks like it's dropping about a half teaspoon a day.

Thanks.

[creaturecat]

drop some oil out of it. see what happens.
overfill can cause oil to drip from the top - downward, of course
I have always loosened the oil tank drain plug to drop some oil.
Make sure oil is cold.
Clean around the p/s clamp, then check for leaks.
The p/s leak should be attended to.

[aigel]

I also do not think the oil leak is caused by overfill. Generally overfill will lead to oil being sucked into the intake and being burnt in the engine - blue smoke out the tailpipe. It also sounds like the overfill is minor. But as discussed above, it is no problem to let some out the oil tank by carefully opening the drain plug - not completely pulling it out. Use a very clean container, so if you drop too much, you can always pour it back in the top without spending $$$ on fresh oil.

For you to be able to do any diagnosis, the engine cover / shield has to come off. There is no way of telling where it is coming from otherwise. It is okay to drive without the engine cover. Report back with some pictures and we can help you further, I am sure.

I don't appreciate every poster on the 993/964 board here being sent to Rennlist. That's not how we ever get traffic up on this board. If you ever spent significant time on Rennlist, you know that there is more to a board than just the technical contents.

George

[Don Settergren]

Take off the undertray and look around. The under pan can hold a lot of oil and divert it a long way from the actual source. Take photos of the leaky area and post them. You might have to clean the bottom end and then drive and wait for the leak to show itself. Mine leaks a little from a valve cover. I know I should fix it, but no time right now...

[SouthCoastPhil]

+1 on remove under pans.

Then clean it, which will require jacking your car, using jack stands, etc. (do a search, there are tons of helpful threads here).

You cannot determine the source of oil leaks (and we all know that there can be many!) until you clean it, then drive it, then look at the myriad potential sources of leaks.

Oh, and enjoy your new car! 964s are a blast to drive...both street and track!

[Vandit]

look at the myriad potential sources of leaks.

No joke, lol

See this thread for a good look at most, but definitely not all, of those potential areas.
964 Oil leaks & fixes thread.

[bazar01]

+ 1 on removing the engine cover.

I just drive the car's rear wheels up on a ramp, spray degreaser on the engine, let it sit, and rinse spray with water hose.

Drive it around and drive it up the ramp afterwards to search the oil leak source. Take pictures and post.

Don't have to go to rennlist to get some good advise. Lots of knowleadgeable members here.