Mystery of a missing O ring

[brennancarley]

How far can a BMW be driven with a missing O-ring on the filter cap?

Last May I took my 2018 320XI in for scheduled maintenance at my local BMW dealer.

About 8,000 miles and 9 months later (the car doesn't get driven a lot, rarely more than 40 miles at a time) I was taking a long drive (driving from NYC to Sugarbush, VT), and ~250 miles into the trip I got an alarm on the dash saying "Engine oil pressure too low: stop carefully and turn off engine.")

IMG_5468.jpg

I stopped, let the car cool down, and drove VERY slowly the remaining ~70 miles to my hotel. The next day I drove very slowly to the local BMW dealer (~30 miles). The alarm did not come on again.

The dealer in Vermont reported that oil pressure was fine, but that they found the O-ring on the filter cap missing. They replaced it, rechecked the oil pressure, and cleared the fault. And charged me $132.

BMW Service Report.jpg

I just took the car back to my local dealer for it's annual service, explained the situation, and asked for a credit since the only possible way the O-ring had gone missing was on it's last service at their dealership (i.e. the car hadn't been serviced anywhere in-between last May and this May, and O-rings don't just disappear.)

The local dealer claimed that they couldn't be responsible, as there is no way the car would have gotten far without the O-ring without losing oil and oil pressure. They claimed that oil would be spurting out and the oil pressure would drop dangerously low within 15 miles.

So who am I to believe?
- The BMW dealer in VT that claimed the O-ring was missing?
- My local (NY) BMW dealer who claimed that i couldn't have possibly driven 8,000 miles with a missing O-ring?

[richardodn]

You'll never get a definitive answer as there are simply too many variables. Obviously, you did. There is absolutely no reason for that second dealer to lie. If you wanted to satisfy your own curiousity, you could perform a test by taking off the small o-ring and taking it for a drive. If the oil warms up and the warning doesn't pop then you should feel vindicated. Personally, I wouldn't spend the effort as there's really nothing to gain here.

Whomever you spoke to at the old dealership is an idiot. Their claim that "oil would be spurting out" might be true if the large o-ring was left off. After all that seals the receptacle. However the Vermont dealer explicitly said the small o-ring was missing. This only seals the oil channel. Basically, it appears the service advisor "misunderstood" (i.e. can't read) the situation.

When you were at your old dealership, did you speak to a service advisor or the service manager? If I were in your position, I would write an email to the dealer's general manager & service manager. If you can find it, CC the owner or corporate or whatever is above the general manager. In your email, simply lay out your story like you did above. Be sure to include the response made by the service staff as well as my response to that. If you have that advisor's name, include it. Do not threaten to take your business elsewhere. They may feel they've already lost you as a customer and have no motivation to try and retain you. Make sure they understand your frustration. If you have gotten one of those customer satisfaction surveys, hold onto it for the moment and wait for the dealer's response. At this stage, you want to remain polite and leave them a way to save face.

If you don't get a timely response, then fill it out giving only average scores and let them know that since they don't stand behind there work, you're forced to find someone who will. Now's your opportunity to vent a bit, but try not to burn any bridges.

[brennancarley]

Thanks Richard, very helpful. FYI, the guy that said the oil would be spurting out was the service manager, so I will contact the GM.

One further question, for clarification. If I understand correctly, the large O ring serves as a seal between the oil filter housing and the engine block, so it is REALLY critical. But the small O ring is the seal between the oil filter cap and the oil filter housing... so less critical? i.e. As long as the large O ring is sealed properly, minimal if any oil should get to the small O ring anyway?

[richardodn]

No. There is a gasket that seals between the housing and the block. (The dreaded OFHG; Oil Filter Housing Gasket.) The large o-ring is between the cap and the housing and maintains the seal with the outside world. The small o-ring is smaller than a dime and goes at the tip of the cap. This creates a seal on the oil channel. Watch this video https://youtu.be/Cit65Ov4ZP4?t=361

That probably explains it better than any amount of writing I could do. Also make sure you suggest the SM misunderstood the situation. That gives him an out. (People are weird.)

[brennancarley]

Thank you!