[N54_e90]

Originally Posted by bbnks2

This is false. E8x/E9x was first generation of this OFH. E46 had a much different, albeit similar concept, housing.

Further, this does happen on N54s: https://www.n54tech.com/forums/showthread.php?t=57495

There are a few example posted across various forums. You just don't have people scrambling to forums to complain about it because N54's aren't worth crap and you can buy a used engine for like $1500 now. N55's were put int vehicles all the way out to 2017... plenty of them are still worth big money and still under factory warranty.

Wtf? $1500.00 for a new engine? Let me know where to get one. Also, if you bothered to read that thread you linked, the owner also did a walnut blasting. So it's very likely some debris from that cleaning is what seized his engine...

[Welcome to NBA Jam]

Yeah when I need to do my ofhg in the future I'm strongly considering having a shop do it instead.

[Pladi]

Originally Posted by Welcome to NBA Jam

Yeah when I need to do my ofhg in the future I'm strongly considering having a shop do it instead.

I always think if a shop does it and it seizes on the way home. Will they take any responsibility.

[bbnks2]

Originally Posted by crazythedon

Wtf? $1500.00 for a new engine? Let me know where to get one. Also, if you bothered to read that thread you linked, the owner also did a walnut blasting. So it's very likely some debris from that cleaning is what seized his engine...

If you bothered to know anything about an engine you would know walnut blasting would not seize an engine lol The debris would have to get past the piston rings and even then it would have to get past the oil pickup tube screen and then the oil filter if it did make it into the pan. The only way it could happen would be if the person filled an entire cylinder with shells and literally locked the engine up. That didn't happen in that thread. This was just one example. There are other examples out there. There are examples on N52's as well. N5x all use the same ofh.

And yes, I see N54's for sale for <$2k all day.

[Nick_F]

Did my OFHG about 2 months ago and did not prime the system. Just filled the housing with oil before and really cleaned the surface before installing the new filter. Im curious on the root cause of these failures.

[bbnks2]

Originally Posted by Pladi

I am saying the same thing.. whats false about my comment..

If its the debris that is causing this we would see a wider distribution of this type of failure.

The only other engines this failure would be distributed between would be N52, N54, and N55. And, we do see this failure on N52's and N54's lol. I've already posted links to a handful of examples in one of these older threads. There are only have a handful of N55 failure examples in aggregate outside of rumors.

This style OFH began being used in 2004 with the introduction of the N52 and has carried through all the way to 2017 with the end of the N55 production.

Previous generation engines had a different housing that was more perpendicular and less canted.

here is another N54: https://www.bimmerfest.com/forums/sh...d.php?t=979200

There are actually several N54 owners claiming seized engines after OFHG job in that thread.

Just do some basic Googling.

Again, I'm not saying this doesn't happen after gasket changes. Just pointing out that it is a rare occurrence and that it is NOT n55 specific. With how uncommon it is it leans toward mechanics error more than anything. This job is literally done hundreds of times a day across the country and you have BMW master techs saying in some of these threads in 2018 and 2019 that they have never had this happen and they have never heard of it.

[Pladi]

Originally Posted by bbnks2

The only other engines this failure would be distributed between would be N52, N54, and N55. And, we do see this failure on N52's and N54's lol. I've already posted links to a handful of examples in one of these older threads. There are only have a handful of N55 failure examples in aggregate outside of rumors.

This style OFH began being used in 2004 with the introduction of the N52 and has carried through all the way to 2017 with the end of the N55 production.

Previous generation engines had a different housing that was more perpendicular and less canted.

here is another N54: https://www.bimmerfest.com/forums/sh...d.php?t=979200

There are actually several N54 owners claiming seized engines after OFHG job in that thread.

Just do some basic Googling.

Again, I'm not saying this doesn't happen after gasket changes. Just pointing out that it is a rare occurrence and that it is NOT n55 specific. With how uncommon it is it leans toward mechanics error more than anything. This job is literally done hundreds of times a day across the country and you have BMW master techs saying in some of these threads in 2018 and 2019 that they have never had this happen and they have never heard of it.

I just don't think we have enough information to say that we see this failure equally across N52/N54/N55.

Based on this forum only I think we can conclude that we def see it ONLY on N55. Lol

[bbnks2]

Originally Posted by Pladi

I just don't think we have enough information to say that we see this failure equally across N52/N54/N55.

Based on this forum only I think we can conclude that we def see it ONLY on N55. Lol

I tried to find an example posted on this forum but I can't find one (yet). If you only look at this forum then I guess you're right. This doesn't happen on other n5x. Except it does lol.

Here is another N54: https://www.bimmerfest.com/forums/sh...=882657&page=2

[MartinWake]

happened to me https://www.e90post.com/forums/showthread.php?t=1571755

[Nick_F]

I feel like these failures have to be from debris getting into the system. I guess I dont fully understand the air bubble theory and find that one hard to believe. Seems like a lot of these issues come from diy'ers and not dealerships or indies.

[drwillb]

Originally Posted by Nick_F

I feel like these failures have to be from debris getting into the system. I guess I dont fully understand the air bubble theory and find that one hard to believe. Seems like a lot of these issues come from diy'ers and not dealerships or indies.

As I stated before, I think this problem is debris related.

I just thought of something: if debris gets into the system while the OFH is off, then no amount of priming as per the service bulletin is going to clear it out. If anything, priming will just move the debris along and it may wind up in the pan or it may cause a blockage.

So, is there a reported instance of a DIY OFHG job followed by priming that still wound up in engine seizure? That would start to move the air bubble theory into more questionable ground.

[Pray for Mojo]

Originally Posted by MartinWake

happened to me https://www.e90post.com/forums/showthread.php?t=1571755

Is you car still good a year later with new rod bearings? I don't really buy the oil bubble theory, think it was probably some foreign debris down the galley. It probably happens more than people think and it's a matter of luck whether it blocks something.

[bbnks2]

Originally Posted by drwillb

As I stated before, I think this problem is debris related.

I just thought of something: if debris gets into the system while the OFH is off, then no amount of priming as per the service bulletin is going to clear it out. If anything, priming will just move the debris along and it may wind up in the pan or it may cause a blockage.

So, is there a reported instance of a DIY OFHG job followed by priming that still wound up in engine seizure? That would start to move the air bubble theory into more questionable ground.

Yes, this guy said he primed before starting the car. He said he also dumped oil into the housing itself to ensure there would be oil quicker.

https://www.e90post.com/forums/showthread.php?t=1679198

[MartinWake]

Originally Posted by Pray for Mojo

Is you car still good a year later with new rod bearings? I don't really buy the oil bubble theory, think it was probably some foreign debris down the galley. It probably happens more than people think and it's a matter of luck whether it blocks something.

I had to engine swap it

[Welcome to NBA Jam]

Originally Posted by Pladi

I always think if a shop does it and it seizes on the way home. Will they take any responsibility.

The way I see it is if my engine seizes and I do the work, my only option is BMW NA who will likely do nothing for me. If a reputable shop does it and the engine seizes, I have a few different avenues to go down to get the engine replaced. It's not a fun route to go down, but there are more options there than if the engine seizes after I do the work.

No one knows for sure if this is a design flaw or something that people are doing wrong during the repair. Either way, a seemingly straight-forward repair has caused catastrophic engine failure for some people. I'm more inclined to pay more for someone else to do it in that case.

My OFHG has already been replaced once under warranty and it's been great, so I'm hoping I am in the clear.

[Pladi]

Originally Posted by Welcome to NBA Jam

The way I see it is if my engine seizes and I do the work, my only option is BMW NA who will likely do nothing for me. If a reputable shop does it and the engine seizes, I have a few different avenues to go down to get the engine replaced. It's not a fun route to go down, but there are more options there than if the engine seizes after I do the work.

No one knows for sure if this is a design flaw or something that people are doing wrong during the repair. Either way, a seemingly straight-forward repair has caused catastrophic engine failure for some people. I'm more inclined to pay more for someone else to do it in that case.

My OFHG has already been replaced once under warranty and it's been great, so I'm hoping I am in the clear.

Yeah i hear what ur saying. For me i guess since i have done the work twice with no issues i am more inclined to do it again if i have to. I can see if uv never done it after all these stories you might be more reluctant.

[MPESTO]

I just wanted to add another sample. I did my ofhg and valve cover on my n55 last month and has been fine ever since. I did not prime the system after just did a oil change while I was there.

I too think that debris getting in there is causing it.

[TheGoodTheBadTheUgly]

When I did it I didn't even own a torque wrench back then or anh specaized tools, but I took all the precautions I could and used brake clean to wipe as much of the exterior of the OFH before doing the job. I saw many DIY where this is not mentionned but I think it's the most important step because sometimes when taking it apport loose dirt can fall in.

Didn't prime the system too. Shouldn't need priming in my opinion since it's pretty much the same concept as oppening the oil cap.

If you are really paranoid, wash the hood too before because sometimes it can carry a good ammount of dirt.

[JPuehl]

I'm an amateur mechanic and this past year replaced the OFHG, due to leaks, in both my car, '12 135i w/N55 and my wife's car, '13 E93 335i w/N55 and had no problems what so ever. I doubt changing the gasket was the cause of the failure.

[rich_mane]

I did literally hundreds of the OFHG job at the dealership without ever having a failure. There were some guys there that had 2 or 3 failures each that always seemed to happen after doing the OFHG.

My motor seized like 3 miles after the job (3rd time doing it on my car.) I didn't prime, but let it idle for a fair amount of time before driving. I thought that'd be fine. I think the vapor pocket theory has some legitimacy. #4 and #5 rod bearings spun on my car, and I didn't see any type of debris or dirt blocking any passages to cause it. And I know I was careful enough to not drop anything down the oil port. But the windage tray was clearly burned from the heat those two rods were producing. Might have been slowly gettin worse and just bad timing with my OFHG job. Idk, it's still running after the bearing replacement lol. Just did tires, brakes, and water pump/tstat so I hope it keeps running.

I'm surprised this is still being discussed haha