oil spray on the boot! - The Unofficial BMW M5 Messageboard (m5board.com)

Prutser · 12th August 2003, 02:10

Last friday I finally drove my 3.8 flat out on the German autobahn. Unfortunately it was during daytime, so there were plenty of cars, but I did get two successful runs.

I noticed two things:

First is that when I hit 265km/h (at appr 6900rpm I think) it felt like the power from the engine was suddenly cut, although I hadn't reached the rev limiter yet. It happened both times and it felt like I couldn't push the car above 265km/h. Could this be the speed governer? 265 on the speedometer might just be a more realistic 250km/h in real life.

Second and more frightening was that when I parked the car after the runs, I noticed a fine spray of very small oil drips all over the back of the car. I've never seen this before on this car, but I did have a similar experience with my previous E34 535i when the engine blew up at WOT.
Obviously I didn't blow the 3.8 and it still runs like it used to, but where does this come from?
Am I in trouble??

Steven · 12th August 2003, 05:14

Pruster,
The oil problem sounds like blow-by. Have the compression checked, you may be burning oil. This could also present a problem for the cat and both silencers by the way of oil fouling. Good luck, I hope the compression is fine and it's just a seal or something minimal.

simone76 · 12th August 2003, 13:27

My opinion is gearbox or rear diff are loosing oil that with hi speed are spread on the boot
give a check under the car

keep us posted

ciao ciao

Prutser · 12th August 2003, 14:45

Well the gearbox is leaking indeed and has been leaking for quite some time already. In fact, over the years it has lost so much oil that it deteriorated the silent blocks that support the gearbox. I had those replaced earlier this year.
My mechanic says its the outgoing axle seals that are leaking and he suggests replacing them in the near future for around 200 euro.

However, my mechanic also said it wasn't leaking that much oil and I didn't need to bring oil on my 6200km trip around the Baltic sea. Also, I haven't seen the oil spray before. Could it be that the gearbox leaks *that much more* on very high speed, or is this something else? What about pressure? Is the gearbox pressurized?

Alan Archer · 12th August 2003, 20:06

I had a very similar fright after running the car on a track day.

It turned out to be the differential level plug...

NOT the washer but the PLUG ITSELF,

seems the thread was worn & despite a new washer it wouldnt
seal.

New plug (£5)

no more oil !

Alan Archer.

Prutser · 12th August 2003, 20:28

Forgive my ignorance

, but what's the differential level plug? Something to do with the diff?