[catcher22]

Today's a holiday and this post may be a bit long winded, but I hope other members will find it useful knowledge.

I wanted to write about my experience with the process I took to diagnose and fix an oil leak, which turned out to be a simple leak from my oil filter cap due to incorrect o-rings (parts) that were installed on the oil filter cap. The o-rings were actually properly placed, but were the incorrect parts. The smaller o-ring was slightly smaller than an OEM one. Somehow the oil filter was correct though This was all the result of taking a gamble and allowing the shop I normally have suspension work done on my car (which they're actually great at), do a simple oil change...

From now on I'll always continue to stick to having separate Indy's. One for engine work, one for suspension work, and one exterior work. And most of that work and everything else I will do myself lol.

It was a bit of a process to identify the source of the oil leak and then find a solution. But little investigation saved me over a thousand dollars in repairs, not to mention my time and energy involved in dropping off my car at the shop and all that's involved with that.


It started with a belt squeal on cold startups. I took it to one shop just to investigate and get a first opinion. They said my belts were new (a few months ago I had my engine Indy replace all belts and hoses). I then took it to my engine Indy shop. They told me that oil was leaking all over my serpentine belt, I needed to replace my oil filter housing gasket (OFHG), and the leak was bad.

dirty, dirty oil filter and engine bay


Looking at several hundred dollars in repairs, I wanted to verify the source of the leak myself. I took it to the 24 hour self-car wash on a quiet night and washed my engine bay. I of course took the time to snugly wrap plastic grocery bags around all the engine components that are susceptible to water damage including the ECU box, alternator, DCI air filters. The rest was cake

so fresh, so clean. immediately after engine bay wash, no oil anywhere (cept for alternator which was covered)


I drove home and knew my engine bay would be nice and clean and dry from all the heat. I popped the hood and noticed that the oil leak wasn't coming from the OFHG, it was coming from the oil cap itself!! I actually had mixed feelings because my first thought was 1) I do not need to replace the OFHG gasket, then 2) That damn shop that did my last oil change botched it!!

oil leak from cap only


no oil leak from gasket area on the left


I promptly drove to the nearest dealership and picked up a new oil filter that includes the two o-rings (and metal crusher which I didn't need). The next morning I replaced the oil filter cap o-rings, drove around for a while, and verified no leaks! The best part? Apparently the engine bay wash had cleaned the oil off the belt/pulleys and my engine squeal on startup had ceased. I fixed two issues pretty much at the same time!

In conclusion though, I am kind of disappointed that THREE shops could not identify the source of the oil leak, and that one shop botched a simple BMW oil change. Nobody should botch an oil change! I mean, they didn't need to go to the extent of washing my damn engine bay to find the source of the leak, but at least spray some brake cleaner on the OFH, wipe it down, and REALLY identify the source of the leak! I would bet that if I replaced the OFHG gasket and still had a leak, the shop would recommended replacing the entire Oil Filter Housing (parts alone $200+), ridiculous.

I'm going to have to be much more careful when taking care of my quickly aging car and it is also the reason I posted this for everyone else too. I can only think of how upset and out of pocket and time and patience I would be if I had paid or taken time to replace the OFHG gasket and still have an oil leak! Also, from now on I am keeping my engine bay clean! Happy New Year everyone

[kkasson]

Originally Posted by catcher22

I would bet that if I replaced the OFHG gasket and still had a leak, the shop would recommended replacing the entire Oil Filter Housing (parts alone $200+), ridiculous.

They might change the oil/filter anyway when they changed the gasket, so you might not even know that it wasn't actually the problem.

Do you know what kind of filter they used? Are you sure they actually changed the o-rings? Sometimes they'll leave the old ones and just put a new filter, and the old o-rings will shrink and start to leak. I haven't heard of any brands of aftermarket filter having issues...if they did actually change the o-rings then maybe the new one was just defective?

[Efthreeoh]

I've done 21 oil changes on my car. I've never used anything but an OE filter from the dealer parts department. I've never had a leak.

[Abax335]

Yeah I see it alot at the dealer when after market filters are used alot of them implode and restrict oil flow and the main cap o-ring is never the right size.

If you can spin the cap on by hand all the way its to small. The OE filters cap gasket will get super tight once you hit the gasket and require the filter cup tool to bottom out.

Use mann (OE manufacture) I believe it OE only for the filter. Such a cheap part there is no reason to skimp out on how important it is

[-zd]

Hey Just want to say thank you for posting this. I had this exact same issue.

I am swapping out to OEM filter...because i have had two aftermarket gaskets leak really badly.

[-zd]

and FYI, i also did the housing gasket, thinking it had to be the issue (it wasnt)...also the PS bottle

[jschweighardt]

I bought a used 2009 328i for my daughter.
Car drove great and only had 52k on it. Figured I would not be doing much maintenance for awhile. She came home from college and the car left an oil stain on my new driveway. When I opened the hood I found oil everywhere.
At first I thought the worse, but after further investigation I narrowed it down to the oil filter gasket and the oil cap. Cleaned it all up and took it for a quick drive. Well all around the cap was oil. I had an extra set of o-rings and replaced them, but still leaked. By process of elimination it has to be the oil filter. Yep, MADE IN CHINA. I could not believe they used a non-OEM filter. What did he save, 5 bucks. Dropped a new filter in and its tight as a durm.
Here are some pics and video to help anyone trying to figure out where their leak might be. Enjoy.


https://drive.google.com/open?id=1lu...X_9uBAhY7hXlWt
https://drive.google.com/open?id=1eD...HNMyBkcSOCtYaC
https://drive.google.com/open?id=1xP...yVbaaXJrfKeGCO
https://drive.google.com/open?id=1qp...08x6kGiDouIbcH

[Efthreeoh]

For anyone who reads this post...

The correct OEM oil filter for the N52 is a MANN HU-816. Or the OE BMW filter, which is the exact same part. The BMW filter has "MANN HU-816" stamped on it. The HU-816 MANN/Dealer OE filter is reasonably priced, there is absolutely NO reason to buy an aftermarket brand filter.