Engine Oil Cap

Macpsi · 09-22-2022, 10:42 AM

Background: This past weekend I went for a long drive about 2 1/2 hours. When I arrived back home I got the oil level low dong when turning off the car with the image on the dash. Thought it was odd, because last time I checked the car was full and it does not burn oil. After the drive I was ready to just get in the house anyways so did not mess with the car at that time.

I was going to put the car in garage and when I backed up a fairly good size puddle of oil was underneath the car (~ 4 inches in diameter) and was wet so a fresh leak. Immediately I turn off the car and pop the hood, and I see oil all by the oil cap, by the coils, and down the side of the motor. I take the oil cap off and the little seal on it is out of place. I put it back on good, start the car listen for any noises and put the car in the garage.

Given the car was driven for that long with this oil cap leaking unbeknownst to me, not knowing how much oil has leaked I'm unable to know how much oil is left in the car unless I let it run (because of BMWs being too good for dip sticks).

What I need help deciding and understanding here is:

I'm not too far off from changing the oil. Should I just get a quart or so of some cheap10/40 just so I can pull the car on ramps to change it? I want to be extremely careful since the price of these motors are not getting any cheaper.
Should I worry about any potential engine damage that may have occurred? I did not not hear any catastrophic sounds when it was idling.
I've seen numerous threads on the oil cap leaking, but none to this extreme. Should I get another cap and just frequently monitor for leaks?

NiBe · 09-23-2022, 06:04 AM

Definitely new cap (changed mine week ago

) And new oil, you can inspect the old oil and filter for metal particles (it will be OK is my guess). I think that if you put 1L of oil in you are good to start up the car but if you want to be super careful then change the oil without starting the car first (aka lift it up via different method than ramps).

jun_e92 · 09-23-2022, 12:14 PM

I have the same situation, the paint around the oil filler cap of the oil cap is peeling off, which makes the oil cap seal ineffective. I bought a new cap, and it still leaks a bit. Finally, I sanded off the paint on the oil filler cap and solved the engine oil cap leak by this method.

09-22-2022, 10:42 AM	#1
Macpsi Private 24 Rep 79 Posts Drives: 11 E92 m3 6mt Join Date: Jan 2019 Location: VA iTrader: (0) Garage List 1997 Eclipse GST [0.00] 2002 Lexus IS300 [0.00] 2011 e92 M3 [0.00]	Engine Oil Cap - Leak during Long Drive Background: This past weekend I went for a long drive about 2 1/2 hours. When I arrived back home I got the oil level low dong when turning off the car with the image on the dash. Thought it was odd, because last time I checked the car was full and it does not burn oil. After the drive I was ready to just get in the house anyways so did not mess with the car at that time. I was going to put the car in garage and when I backed up a fairly good size puddle of oil was underneath the car (~ 4 inches in diameter) and was wet so a fresh leak. Immediately I turn off the car and pop the hood, and I see oil all by the oil cap, by the coils, and down the side of the motor. I take the oil cap off and the little seal on it is out of place. I put it back on good, start the car listen for any noises and put the car in the garage. Given the car was driven for that long with this oil cap leaking unbeknownst to me, not knowing how much oil has leaked I'm unable to know how much oil is left in the car unless I let it run (because of BMWs being too good for dip sticks). What I need help deciding and understanding here is: I'm not too far off from changing the oil. Should I just get a quart or so of some cheap10/40 just so I can pull the car on ramps to change it? I want to be extremely careful since the price of these motors are not getting any cheaper. Should I worry about any potential engine damage that may have occurred? I did not not hear any catastrophic sounds when it was idling. I've seen numerous threads on the oil cap leaking, but none to this extreme. Should I get another cap and just frequently monitor for leaks?
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09-23-2022, 06:04 AM	#2
NiBe First Lieutenant 453 Rep 365 Posts Drives: BMW E91 & E92 Join Date: Nov 2021 Location: Europe iTrader: (0)	Definitely new cap (changed mine week ago ) And new oil, you can inspect the old oil and filter for metal particles (it will be OK is my guess). I think that if you put 1L of oil in you are good to start up the car but if you want to be super careful then change the oil without starting the car first (aka lift it up via different method than ramps).
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09-23-2022, 12:14 PM	#3
jun_e92 Second Lieutenant 141 Rep 258 Posts Drives: 2011 E92 M3 ZCP Join Date: Dec 2018 Location: Bay Area， CA iTrader: (3)	I have the same situation, the paint around the oil filler cap of the oil cap is peeling off, which makes the oil cap seal ineffective. I bought a new cap, and it still leaks a bit. Finally, I sanded off the paint on the oil filler cap and solved the engine oil cap leak by this method.
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