Oil in spark plug tubes?
 

Had the car up today and did the plugs. When I pulled the coil packs there was oil in the tubes. The car burns no oil and the plugs are dry. Anyone know why the oil got in there? Am I looking at a major overhaul or just the nature of the car? 98 boxster and thanks fir the replies. Gb

You engine has plastic plug tube with O-ring seals at both ends, which tend to leak over time and require replacement. Do a search, been covered several times............

I don't think it's totally unusual or signs of catastrophic engine failure, but I'll wait with you to hear from other owners with more information. I'd like to know myself.

The plastic tubes crack and the o-rings lose elasticity. Get a set of tubes and rings, replac them all, and you are good for a long time.

Who needs more car owners to comment, JFP knows his $hit better than 99.9% of owners and most Porsche mechanics.

It looks like everyone is in agreement with JFP.

JFP is an amazing resource. His input is truly appreciated. Perhaps you should PM directly if you don't want to hear from others.

When you buy replacement tubes and seals- buy from a reputable source . As JFP and I have discussed and quantified, some aftermarket tubes are out-of-round and some seals(particularly the inner ones) are off- spec. The out of round tubes will never work well with any seal !

Had the same problem on my friend's '98. The O-rings deteriorate eventually. You can buy a pair from the usual sources or a lifetime supply for about the same cost from McMaster. Large are -320 Silicone, small are -121 Silicone

Thanks for the replies. As a newbie. To this Porsche thing I am learning a a lot. I will try to search the site before I ask anything first. Since this is my first 986 i was worried that the oil shouldn't be where it was. I got her all cleaned up, and she is a blast. Thanks again. Gb

Good suggestion. Viton works also. Neither help if the old tubes are cracked or the replacement tubes are o-o-r. Check/measure before you fit. Do not use sealant !

Viton temperature range is rated at -10F to 400F. Silicone is rated at -80F to 450F for the high temperature and -60F to 400F for high purity type.

Thanks for the lead. Is this the correct part for the larger one? (-320)

High-Temperature Silicone O-Rings

These silicone O-rings withstand temperatures up to 450° F. They have a round profile and are suitable for a wide range of static and dynamic sealing applications. All include material certification with shelf life, cure date, and traceable lot number.

Inch O-rings have a dash number and are sized to the SAE standard AS568.
Inch

Fractional

Actual

Dash
Number ID OD ID OD Hardness Specifications Met Temperature
Range, °F Color Pkg.
Qty. Pkg.
Wd.: 3/16 Fractional (0.210" Actual)
320 1 1/8 1 1/2 1.100" 1.520" Durometer 70A (Medium) Made of FDA Listed Material, SAE AS568, SAE J200 -80° to 450° Red 10 1283N263 $6.62

https://www.mcmaster.com/#silicone-o-rings/=17cerk6

The stock O rings are metric? So an Imperial measure will probably be stretched a little or loose. That will affect leakage potential.
Then there is the Durometer issue. There is no OEM spec available.
IMHO better not to try to out-wit the OEM manufacturers on a low cost item like O rings. Just buy OEM from a reputable source - done.
The bigger issue is the spark plug tubes as mentioned above and explained in great detail elsewhere.
First measure the grooves in the tubes for o-o-r. In used tubes, also check for cracks developing.Go from there.

You will have to measure the original O-rings, they are not metric unless they are made to an oddball dimension. Thickness of the large O-ring is 0.210" or 5.334mm not found in any metric listing. Or maybe Febi Bistein is supplying foot and finger O-rings instead of the oddball metric size? The -320 I.D. and O.D. matches the new O-rings in the box. Can you spot the difference between these two?
Silicone is made in only a few durometers and it unlikely Porsche is going to have special special material mixed just for their lowest price vehicle.
Silicone is not the best material for this job as it is not recommended for "most petroleum fluids" by Parker. Included in one box of the Febi tubes was a black small O-ring which usually indicates Buna-N which is recommended for petroleum fluids.
O-rings from McMaster come from USA Sealing and show batch and cure numbers on the package.
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