# Check your oil filler cap!!!



## F1Crazy (Dec 11, 2002)

This is the picture of 3-series oil cap:










What the hell is that build up?! It doesn't look like regular sludge.
Reportedly this buildup happens when BMW synthetic oil is used. 
I don't have it on my car but if you guys can check yours and report your findings, also tell what oil you use.


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## The RedShift (Dec 31, 2002)

Almost 15K miles. No build up here :thumbup:


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## Alex Baumann (Dec 19, 2001)

Hmm, interesting, I'll check it. I only have 4000 mls though.


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## Sean (Dec 22, 2001)

Hmm...not good. :yikes: I've noitced that on one of my BMWs, but I don't remember which one. I'll have to take a look.


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## mwette (Sep 16, 2002)

My 03 330 Ci looks clean at 10,500 but I did change oil at 7500.


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## The Roadstergal (Sep 7, 2002)

That looks like rust? A rusty dipsitck is usually a sign that the car has been driving on short (not-warmed-to-operating temp) trips for the most part...


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## F1Crazy (Dec 11, 2002)

The Roadstergal said:


> That looks like rust? A rusty dipsitck is usually a sign that the car has been driving on short (not-warmed-to-operating temp) trips for the most part...


Right, it looks like some sort of oxidation!

Alex, I thought that you use TWS Motorsport, if that's the case I don't think you have to worry as the person that took the picture says it happens only when BMW High Performance Synthetic is used (for N.A. it means Castrol TXT Softec Plus 5W-30). 
I hope the deposit is not oil related, since BMW Synthetic looks like a very good oil.

Please post not only miles on the car but also what oil you use. TIA.


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## The Roadstergal (Sep 7, 2002)

F1Crazy said:


> Please post not only mileage but also what oil you use. TIA.


And the length of your commute?


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## Patrick (Dec 23, 2001)

My 09/2002 build E39 just turned 12,000km :eeps: and I am due for an oil change. Checked the cap last week - just for the hell of it, after I opened the hood for the second time ever  

I am clean.

:yikes: 

-


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## F1Crazy (Dec 11, 2002)

The Roadstergal said:


> And the length of your commute?


OK, I've changed it a little, happy now?!


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## The Roadstergal (Sep 7, 2002)

F1Crazy said:


> OK, I've changed it a little, happy now?!


:clap: :AF330i:

Did a moderate overhaul on the ancient E30 engine about 3000 miles ago, cap clean, dipstick clean, Castrol (same make as BMW) GTX dino, never drive it without getting it to temp.


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## F1Crazy (Dec 11, 2002)

For comparison this is what oil cap on my car looks like:


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## PABS (Apr 3, 2003)

Two BMW's - 45k and 160k - both clean oil caps. Always used Castrol Syntec.


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## vern (Apr 19, 2002)

*Film*



F1Crazy said:


> This is the picture of 3-series oil cap:
> 
> 
> 
> ...


I change oil and filter about every 6500 miles with Castrol Syntec and have 27,000 miles on the car .All I can find on the in side of the filler cap is a slight film of rust but no sludge.
vern


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## drmwvr (Feb 21, 2003)

Here is mine with BMW synthetic. I only have 7k on the odometer so I am not suprised that it looks as clean as it is. I guess you can use this as a base line. :dunno:


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## LmtdSlip (May 28, 2003)

It would be interesting to do an oil analysis of your current fill and see if it points to anything that could cause that buildup on your cap.


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## rwg (May 10, 2002)

I seem to remember reading about this on Bimmerforums some time ago. Iirc, the consensus was that sludge buildup on the cap is caused by condensation that gets into the oil b/c the car is driven on quick trips and the oil doesn't have time to warm up enough to burn the condensation out. The type of oil used was not supposed to matter.


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## Sean (Dec 22, 2001)

Here are mine. The 1st one is from my 1992 525ia with 133,5XX miles and the 2nd is of my 2001 330Ci with 14,4XX miles.

The oil and filter are changed in the 525 every 3500-5000 miles with Valvoline 10W-30 and the oil/filter in the 330 is changed every 3000-3500 miles with BMW Synthetic Oil 5W-30.


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## operknockity (Apr 19, 2002)

Mine looks just like drmwvr's and I've got 21K+ miles on mine. Have changed the oil at 5K, 10K, 15K, and 21K with stock BMW 5W30 synthetic, and will continue to change it on a 7.5K (plus or minus) interval basis, though I may switch to Mobil 1 after a while.


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## doeboy (Sep 20, 2002)

operknockity said:


> Mine looks just like drmwvr's and I've got 21K+ miles on mine. Have changed the oil at 5K, 10K, 15K, and 21K with stock BMW 5W30 synthetic, and will continue to change it on a 7.5K (plus or minus) interval basis, though I may switch to Mobil 1 after a while.


That's interesting... depending on how my car runs on Mobil 1 0W-40, I may be switching back to BMW 5W-30 Synthetic. :dunno: We'll see after my next oil change which is coming up soon... did my first change at 4600... I'm at about 9200 now, so I'm getting close...


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