So what damage, exactly, is done by overfilling oil?

[LeRoux Strydom]

Being a first-time owner for 5 months now, very early in our mutual relationship I did the time-honoured deed of overfilling the oil level on my SC.

Now I would like to know, exactly what damage have I done to pipes or seals? I checked the oil level as per the book, then overfilled and turned the car off for the night. Where did the oil come out that formed the big pool under the engine the next morning? The crankcase breather? Does this have any relation to the few drops the car leaves on my garage floor every night?

Judging from the crap I had to clean off the underside it was leaking when I bought the car, but now that it is clean, it seems to "sweat" from somewhere on the passenger side valve cover. I am considering installing new valve cover gaskets, but would like to fix any possible damage from the overfilling at the same time.

Any suggestions and comments to enhance my knowledge will be appreciated.

LeRoux

[Jim Sims]

I doubt you did any damage; you just made a bit of a mess. The oil likely ended up in the bottom of the air box; if your car has a CIS system in OEM condition the bottom of the air box has a drain line which goes out through the sheet metal near the front right of the engine. This line goes to a rubber "duckbill" type drain valve mounted on the engine sheet metal just back of the starter. Take off the air filter cover and the air filter and look at and feel the bottom of the air box for oil. A 911 engine can leak from may places: engine sump plate (from being warped by having the nuts overtightened), oil return tubes (old and hard o-rings), case centerline seam (old or disturbed sealant), case tie bolts (hard or damaged o-rings), breather cover gasket, hose from breather cover to oil tank (hardened and no longer sealing), engine mounted oil cooler seals, engine mounted oil thermostat o-ring, oil pressure switch (leaks at body crimp), rocker shafts (leak through bores) in cam towers, valve cover gaskets, joints between heads and cam towers (old or disturbed sealant), chain cover gaskets, oil lines including cam tower lines, o-ring around no. 8 nose bearing, crankshaft seal at pulley end, and so on. Your best bet is to clean off the engine and look for the source of the oil leak(s). Cheers, Jim

[Jdub]

You will also want to detach the tube at the oil fill spout that sits just below the cap. Do what you need to to lower the tube and drain the oil out of that.

Carefully wipe the excess oil from the sensor plate, both top and bottom. To do this you will need to remove the rubber plenum that sits from the top of the throttle body to the airbox. This gives you access to the top of the sensor plate. Lots of Simple Green or equiv. cleaner will take care of this.

Really, the thing to do is, after being sure that you have the correct amount of oil in the car, to go ahead and drive the heck out of it for awhile. This will work much of the excess oil out.

You might also replace the spark plugs depending.

John