Help! Oil cap problem

[heart_doctor]

I have a 2011 e92 m3. 27,000 miles. The day before yesterday the add 1 quart light alert came on. I stopped an added 1/2 quart of approved oil. At the time I didn't realize that the gasket seal has come loose from the oil cap. It was still in position on the engine. I replaced the oil cap and the fit seemed nice and tight. I drove to pick up dinner and it took a long time for the engine oil level to come up again and it said to add a quart. I didn't believe it so I parked in a level road and reset the oil gauge and the oil reading was fine.

I went home parked the car in te garage. The next morning I went outside and started the car and let it warm up like I always do and when I pulled out I noticed a puddle of oil under the car. (Not large) Again the oil level was perfectly fine by the oil gauge. I shut the car off. Openned the hood and sure enough oil was leaking from around the oil cap. I took the cap off and the seal was bent and not in place. When I touched the seal it had a gritty feel to it and the material was black on my finger.

I put the oil cap back on, without the seal and called the dealership and they ordered a replacement which will be here Monday.

I have two concerns. I drove the car approximately 26 miles with the oil cap leaking. I am also concerned that the seal has a gritty feel to it and the material on my finger was black. I change the oil every 7500 miles electively. I don't wait the 15,000 miles BMW recommends

Do you think I did any damage to the engine? Why was the gasket/seal "gritty"?

I plan on going long with the car.

[Petros]

do you have the old design oil cap? it sucks for the reasons you stated. i replaced mine with the newer design and so far so good.

[heart_doctor]

Originally Posted by Petros

do you have the old design oil cap? it sucks for the reasons you stated. i replaced mine with the newer design and so far so good.

This will be the second oil cap. I just get what the dealer gives me. Do you think I damages my car? Is that gritty feeling normal?

[Beemdog]

Originally Posted by heart_doctor

I have two concerns. I drove the car approximately 26 miles with the oil cap leaking. I am also concerned that the seal has a gritty feel to it and the material on my finger was black. I change the oil every 7500 miles electively. I don't wait the 15,000 miles BMW recommends

Do you think I did any damage to the engine? Why was the gasket/seal "gritty"?

No damage. Positive crankcase pressure will generally drive more air out in opposition to the PCV system vacuum drawing air into the engine, so outside dust contamination is minimal (a small amount of airborne dust is not likely to create any issues--older cars used to run vented oil caps for decades). Driving it for 26 miles like this is insignificant. The seal material will generally rub off black even if clean due to natural oxidation of the seal-- just like those around your windows. Old oil seals also form a glazed layer on them that feels gritty when disturbed and broken up into bits.

You likely only lost a few ounces of oil driving with the leaky cap. I'd be more concerned about getting the engine compartment cleaned up than any risk to your engine.

[heart_doctor]

Engine compartment is not that bad. Just around the cap itself. I am bringing it to dealer on Thursday, needs an oil hangs anyway.

[aussiem3]

My oil cap is still the original '07 build and no issues with leaking.

[m3ray]

Buy a new oil cap.

[heart_doctor]

Originally Posted by m3ray

Buy a new oil cap.

Wow. Really? Great advice!

[MFL]

Originally Posted by heart_doctor

Wow. Really? Great advice!

Well, what do you expect? Replace it, drive the car, have fun. If it breaks, that's why you have a warranty. What's the damn problem here?

Or do you just want people to put on their tinfoil hats and speculate as to what you did or did not damage by driving it?

[Dave07997S]

Where the oil cap gasket touches the valve cover, if the valve cover is chipped you can replace the oil cap until hell freezes over it will still leak. On my 2011 M3 I took it in for an oil service, after that oil service the car was going through oil. I checked the oil filler and sure enough oil has been leaking out of the cap. I popped the cap and I notice the dealer when they changed my oil chipped the valve cover right where the gasket seals against it. They changed my oil cap and sure enough it leaked again. The powdercoating on the valve cover around the oil cap gets brittle from all the heat and chips very easily.

Dave

[JamesM3M5]

Typically it's not something anyone does to chip it off; it flakes off on its own or sticks to the underside of the cap when removing it normally. The alloy used for the valve covers has been prone to weird corrosion since 1992. They started using a lot more magnesium in it to reduce weight. It allows the coating to flake off and cause leaks under the cap and also around the gasket. Annoying and expensive.

You can either replace the covers and gaskets OR remove the covers, carefully file down the coating to clean, bare metal on both the VC gasket surface and the oil cap surface, and reinstall the covers with a thin layer of Hylomar or Permatex Aircraft Gasket Maker between the cover and gasket. That holds well for many years, even with the really crappy alloy used on the 90s M50/S50US/M60.

[heart_doctor]

Originally Posted by MFL

Well, what do you expect? Replace it, drive the car, have fun. If it breaks, that's why you have a warranty. What's the damn problem here?

Or do you just want people to put on their tinfoil hats and speculate as to what you did or did not damage by driving it?

I already have one in order. I was concerned because I thought I may have damaged my engine. Read my original post.

[Groundpilot]

Originally Posted by JamesM3M5

Typically it's not something anyone does to chip it off; it flakes off on its own or sticks to the underside of the cap when removing it normally. The alloy used for the valve covers has been prone to weird corrosion since 1992. They started using a lot more magnesium in it to reduce weight. It allows the coating to flake off and cause leaks under the cap and also around the gasket. Annoying and expensive.

You can either replace the covers and gaskets OR remove the covers, carefully file down the coating to clean, bare metal on both the VC gasket surface and the oil cap surface, and reinstall the covers with a thin layer of Hylomar or Permatex Aircraft Gasket Maker between the cover and gasket. That holds well for many years, even with the really crappy alloy used on the 90s M50/S50US/M60.

Thanks for the info Learned something new.
Just looked at this Hylomar gasket maker, and it sounds like a good solution for oil leaks in general:

"Hylomar is a polyester polyol–based compound that turns from a gel into flexible putty within minutes of application. Originally developed by Rolls Royce, where it performed under the most stringent aerospace tolerances, Hylomar brings superior qualities to automotive applications. Its non-hardening formula maintains seal integrity even when subjected to thermal distortion and vibration".

[edwinm3]

mine never leaks, make sure you clean everything really well every time your take it off

[enycerz]

its actually the powder coating on the valve cover that cause all the issue.

[m3ray]

Originally Posted by Dave07997S

Where the oil cap gasket touches the valve cover, if the valve cover is chipped you can replace the oil cap until hell freezes over it will still leak.

Originally Posted by enycerz

its actually the powder coating on the valve cover that cause all the issue.

Nothing that a good scouring pad and some solvent cleaner wouldn't fix.