Just replaced my oil cap...

[THE TECH]

Interested to hear your results.

[Singletrack]

FYI - No leaks since I last cleaned the rubber seal, lubed the cam cover, and re-installed the cap.

[dale.b]

Originally Posted by Singletrack

FYI - No leaks since I last cleaned the rubber seal, lubed the cam cover, and re-installed the cap.

How many miles?

I have 70k. I am wondering if higher mileage = more blow-by and then some oil seeping past the cap.

I measured the distance between the oil cap arm and the gasket.

Old cap arm is 5mm from the gasket. New cap arm is 4mm from the gasket.

[surlynkid]

Dale - are the edges squared off like a gasket or round like an o-ring? Do you have access to a tool to measure the durometer?

[dale.b]

Okay, so I tried sealing two gaskets together on the old cap.

I took the gaskets out of the caps. I bought an old version of the cap, and even brand new it came pre lubed with oil on the back side. I cleaned the gaskets up with some brake cleaner.

I used high temp liquid gasket on one surface, but left room at the edge of the gasket for the cap lip to grap on to. Yes, that's Hondabond.



Then I mate the surfaces. Some liquid seeped to the inside as I pressed the surfaces together. I just wiped it aroud the inside and cleaned off the excess.


Then I put the double gasket in teh old cap. I put the outside edge in first and made sure teh cap lip grabbed the bottom gasket. Be sure you get the bottom gasket to be grabbed complete around the circumference. You'll notice that the inside edge buldges up. That is because the top gasket is getting pushed by the cap lip.


I used a digital caliper measured the distance from the cap arm to the gasket flush agains the cap. it is 2.77mm.


I lube the gasket surface and the vanos surface, and I put the cap on carefully so that the gasket doesn't buldge up or detach (since it is still wet).

I take it off to check, and the gaskets are still properly adhesed together. I put the cap back on. And now I am waiting for the liquid gasket to dry.

[Singletrack]

Originally Posted by dale.b

How many miles?

I have 70k. I am wondering if higher mileage = more blow-by and then some oil seeping past the cap.

I measured the distance between the oil cap arm and the gasket.

Old cap arm is 5mm from the gasket. New cap arm is 4mm from the gasket.

Attachment 714655

re: blowby - possible I guess. Can do a compression/leakdown if worried I suppose.

Thanks for the info - makes sense.

[Singletrack]

Originally Posted by dale.b

Okay, so I tried sealing two gaskets together on the old cap.

I took the gaskets out of the caps. I bought an old version of the cap, and even brand new it came pre lubed with oil on the back side. I cleaned the gaskets up with some brake cleaner.

I used high temp liquid gasket on one surface, but left room at the edge of the gasket for the cap lip to grap on to. Yes, that's Hondabond.

Attachment 714664

Then I mate the surfaces. Some liquid seeped to the inside as I pressed the surfaces together. I just wiped it aroud the inside and cleaned off the excess.
Attachment 714665

Then I put the double gasket in teh old cap. I put the outside edge in first and made sure teh cap lip grabbed the bottom gasket. Be sure you get the bottom gasket to be grabbed complete around the circumference. You'll notice that the inside edge buldges up. That is because the top gasket is getting pushed by the cap lip.
Attachment 714666

I used a digital caliper measured the distance from the cap arm to the gasket flush agains the cap. it is 2.77mm.
Attachment 714667

I lube the gasket surface and the vanos surface, and I put the cap on carefully so that the gasket doesn't buldge up or detach (since it is still wet).

I take it off to check, and the gaskets are still properly adhesed together. I put the cap back on. And now I am waiting for the liquid gasket to dry.
Attachment 714668

What's the temp rating on that liquid gasket if I may ask?

[dale.b]

Originally Posted by Singletrack

What's the temp rating on that liquid gasket if I may ask?

600f, 315c

I just came back from 30min of fun with the car. No sign of any leak or seepage.

I hope it stays that way.

[Singletrack]

Nice. Keep us posted. I have an extra gasket laying around myself.

[dale.b]

Originally Posted by surlynkid

Dale - are the edges squared off like a gasket or round like an o-ring? Do you have access to a tool to measure the durometer?

Hey surlyn, the edges are square. Unfortunately, I don't have a durometer.

[pbonsalb]

On some of the BMWs made in the last 20 years, the crankcase and/or valvecover vent system fails. The result is that the crankcase cannot vent and oil forces its way out the easiest gaps. If this is the case and you seal up the oil cap really tight, expect trouble eventually at less easy to remove and service engine seals.

Always think about why the problem is occurring. Is this happening on 2 year old cars with 20k or mostly 4 year old cars with 40k?

I have not studied the crankcase breather system on this car yet, but I have replaced them on E36 M3, E39 528i and E46 325i. Hopefully, BMW has improved them.

[Singletrack]

Mine has always leaked off and on since new.

[BMRLVR]

When my car was almost about 2 weeks old I had some leaking around the oil cap. I bent the retainer arms on my cap ever so slightly to put more preload on the gasket, never had a problem with leaking since!

[pbonsalb]

I bought my 08 E90 M3 used with 30k and it now has 45k and no issues with the oil cap yet.

[tibra1]

Thanks guys I will be keeping an eye on mine

[TxStig]

Sorry to revive an old thread, but is this gasket/o-ring leak still a problem?

[biggynuts01]

Bought my car used with 27k miles on it. Now im at 44k miles not a single drop of oil so far.

[TxStig]

Originally Posted by biggynuts01

Bought my car used with 27k miles on it. Now im at 44k miles not a single drop of oil so far.

Think people would be interested in a billet cap?

Something a little more durable...I could probably make with a price of $40-$50 shipped.

[m3an]

Originally Posted by TxStig

Think people would be interested in a billet cap?

Something a little more durable...I could probably make with a price of $40-$50 shipped.

yes, def. There's a billet cap on Ebay cheaper, but I just don't trust the underside and fear it failing and getting in the chain/cam gears and doing a lot of damage

[lookitsma]

I haven't burned a single oz of oil nor had it leak. Is it possible that there is too much oil in your engine to begin with and overfilling causing it to build too much pressure? I've seen dealerships overfill oil on these cars and its apparently pretty common since they forget its liters and not quarts on the TWS bottles. Maybe they just don't let it warm up first. Who knows. This is the FIRST sports car I've had that has not burned through a quart of oil and I make sure the quantity I put in is right.

[aussiem3]

Touch wood, it has been five years and 35k km, and no such issues. Unless, the caps for the US is different to EU and the rest of the world. I wouldn't be happy if this had happened to me.

[lookitsma]

I'm sure the caps are all the same.