[KevinC39]

There's a couple threads on the first and second pages of the N55 section of E90Post about rod bearings, seized engines and ofhg changes. It's a lot bickering back and forth to wade through but that's where I first heard of priming after changing the ofhg. Seems like a few people had engines lock up after having it changed. Here's a link to one of them.
OFHG Replace and Engine Seized. No Metal Shavings or Coolant in the Oil

[JuniorB]

Omg dude! Had no idea, makes no sense!

[chadillac2000]

Wow thanks for sharing. Will definitely be priming the system going forward when I touch any of these gaskets.

[anthracite]

Guess you need to prime the engine every time you change the oil filter? Seriously? Changing the OFHG is no different than changing your oil filter and you don't prime it every time you do that.

Steve

[codesx]

Originally Posted by davidponi

N55 here, just did the OFHG and same problem. Drove 20 mins after the replacement without indication of an issue. Accelerated from a stop to approx. 3500rpm and the car went to 0rpm. The starter tries but the crank won't budge, lots of resistance manually cranking it. The car has been meticulously maintained and I'm stumped, surgery begins in the morning

Hey davidponi,
Strictly curious;
Did you do this work yourself?
If so, how long was it left apart before reassembled?
Have you drained your oil to look for coolant?
When you pull your OFH back off, is the gasket in good shape, or pinched and out of place? (allowing coolant/oil to mix)

Ignorant thoughts below
For all these engines to seize so quickly after the OFHG replacement, it does suggest lack of oil flow vs. coolant in the oil, which would take longer and have a visible result (more easily identifiable).
If the lack of oil is suspect, this would have to be fresh-oil-flow.
That would suggest either debris in an oil channel, or that an air bubble could in-fact stop the oil flow unless purged (again, I don't know the oil flow well enough to put personal belief in this).
Turning the engine to prime would not purge a bubble any better than running the motor. Nor would it push debris through better than running the motor. (if said debris should be pushed through)

Possibilities
-Coolant in Oil: Takes a decent amount of coolant vs oil and a bit more time to kill bearings, and would be very evident when the oil is drained and checked.
-Air Bubble: Wild speculation, just reaching for a difference between changing the oil vs. removing the OFH.
-Debris: Could definitely impede oil flow to the point that it could quickly seize an engine.

Rate as which engines die following OFH removal/installation
-Average reports appear to be 10-35 minutes of driving, which is suggestive of oil starvation

Leaves us with the same question
-Why is the oil ceasing to flow after the OFH is removed/installed

At this point, I tend to think that turning the engine over to 'prime' does little in this scenario.

I'd like to see the specs of the people that have replaced their OFHG and not primed vs those that did it followed by priming - then compare that against who's engines seized.
I speculate that the vast majority of these cars have had their OFHG changed, with only a minute percentage having primed afterwards. If so, the 'priming' subject may carry much less weight.

(if 100% of primed engines didn't seize (100% of the 2~% of total jobs done), while 4% of the 98% total jobs did seize... then priming has strictly speculate benefit... potential, but purely speculative, and is thus a distraction to the real issue, which I presume is oil starvation... reasons unknown)

[JuniorB]

I read that thread, still no evidence of how a gasket repair seizes a bearing. Looking at the housing itself, it’s all open ports but the thermostat,if you drain a tad bit of coolant to below the lower coolant port, it will eliminate any chance of any coolant entering the pan. If you drain the oil in the pan, you eliminate any dirty oil. Trying to fathom how the two are related to each other, is there anyone loosing an engine due to just an oil change?, motor or head work? I’ve done this same procedure on my n52, I let it run for a while before I drove it, that motor is an exact to a n54 as far as bottoms go, they all use the same bearings, housings, and oil pumps.

[HouseN54]

Official Bmw repair instructions state to drain coolant fully. Loosen oil cap and let drain. Engine MUST be cold.

[davidponi]

codesx, I removed the oil filter housing unit on April 12th. Had the outside of the unit polished while I replaced the belt and tensioner. Reasssembled everything on Tuesday the 16th to spec. Filled with 50/50 and did the electronic bleeding procedure until there were no more air bubbles and the level remained @max. I should mention that the bleeding procedure took longer than the expected 12 minutes. Regardless, filled with 6.5L of oil, some via the oil filter housing unit, but most via the engine. Drove 15 miles without any warning lights, then coasted into a Mr Bubbles car wash after I lost power. Oil never read over 220, but why didn't it go into limp mode or show any signs of an issue before completely locking up? Still trying to free up the lift but the oil cooler seal looks good.
Edit: Also, after completing it all I let the car idle for about 5 minutes while I looked for leaks and lights. Everything checked out. Went and grabbed lunch, came back to drive the car home from the shop, and made it 15 of the 16 miles

[Magnusk77]

Originally Posted by chadillac2000

I've always been interested to know the difference between:

a) unplugging the injectors and letting the starter turn the engine over without the engine actually firing.

b) just starting the engine.

Wouldn't both result in rotating parts moving while dry for just a brief moment either way?

Yes but from what I understand if an engine starts to rotate without combustion it essentially puts no load on the bearings or other moving parts. So if anything is dry or not 100% lubricated it may not result in a spun bearing or extra wear. How much wear is another story, it may not actually be significant at all but who knows. Just one of those preventative measures I guess.

[THE BEAST]

Still has load. Remove spark plugs for a free, non compression, spinning fixture.
As I said b4, true priming means no moving or rotating parts while oil gets to them.

[Magnusk77]

Originally Posted by THE BEAST

Still has load. Remove spark plugs for a free, non compression, spinning fixture.
As I said b4, true priming means no moving or rotating parts while oil gets to them.

True that would be better. Still compared to combustion I imagine the load would be a lot less. Don't think you can "truly" prime these engine so it would be the next best thing if it's actually needed.

[blown07]

A simple solution for priming the oil anytime that I did a few years ago is to solder/rubber tape a wire to the solenoid wire going to the starter. This wire is about 18" and comes out to where the main vacuum line is and is protected with male/female crimp to prevent a short. When I wanted to prime the oil when I did turbos, once a week during winter storage, Oil change and just for fun I grab my remote starter button and connect one of the alligator clips to the +ve battery post in the engine bay and the other to the new wire I added. Takes about 20 seconds to do and nothing to remove/doesn't hurt a thing. I'm auto so you would need to be very careful with a manual car.

[Tallicia]

This is very intriguing. I'm curious about, how this OFH replacement took days.

If coolant was not drained and some went into the oil passages, and it sat or basically cleaned off any oil and left coolant residue that harden caked, especially on bearings, they could in fact be starved, and heat up, expand under load in just a few minutes and seize. or the coolant could be cooking/burning on the bearing.

Also, I would normally expect this procedure be completed in less than a few hours, so spillage/contamination has less time to have corrosive effects. Sealed systems are not well behaved for long periods when not sealed.

I just replaced my valvetronic motor and eccentric shaft, but still the entire thing was done in hours, not days, and no issues. My oil changes have as much oil extracted from the OFH on each oil change and oil pressure is always good.

My 2 questions:
Can those affected confirm with high certainty, no coolant went into oil passages?
How many of these were left to sit/open for extended periods of time?

[autoart]

Someone would have to do a blackstone oil sample check on their seized engine to see if coolant is in the oil.
I have heard that if you undo the drain plug 1st. oil sprays out before you open the oil filter, like its pressurized.
I don't understand it either.

[Alex@abrhouston]

Originally Posted by anthracite

Guess you need to prime the engine every time you change the oil filter? Seriously? Changing the OFHG is no different than changing your oil filter and you don't prime it every time you do that.

Steve

no, theres a check valve in the housing which isn't disturbed doing an oil service, so its not the same scenario

Originally Posted by codesx

Hey davidponi,
Strictly curious;
Did you do this work yourself?
If so, how long was it left apart before reassembled?
Have you drained your oil to look for coolant?
When you pull your OFH back off, is the gasket in good shape, or pinched and out of place? (allowing coolant/oil to mix)

Ignorant thoughts below
For all these engines to seize so quickly after the OFHG replacement, it does suggest lack of oil flow vs. coolant in the oil, which would take longer and have a visible result (more easily identifiable).
If the lack of oil is suspect, this would have to be fresh-oil-flow.
That would suggest either debris in an oil channel, or that an air bubble could in-fact stop the oil flow unless purged (again, I don't know the oil flow well enough to put personal belief in this).
Turning the engine to prime would not purge a bubble any better than running the motor. Nor would it push debris through better than running the motor. (if said debris should be pushed through)

Possibilities
-Coolant in Oil: Takes a decent amount of coolant vs oil and a bit more time to kill bearings, and would be very evident when the oil is drained and checked.
-Air Bubble: Wild speculation, just reaching for a difference between changing the oil vs. removing the OFH.
-Debris: Could definitely impede oil flow to the point that it could quickly seize an engine.

Rate as which engines die following OFH removal/installation
-Average reports appear to be 10-35 minutes of driving, which is suggestive of oil starvation

Leaves us with the same question
-Why is the oil ceasing to flow after the OFH is removed/installed

At this point, I tend to think that turning the engine over to 'prime' does little in this scenario.

I'd like to see the specs of the people that have replaced their OFHG and not primed vs those that did it followed by priming - then compare that against who's engines seized.
I speculate that the vast majority of these cars have had their OFHG changed, with only a minute percentage having primed afterwards. If so, the 'priming' subject may carry much less weight.

(if 100% of primed engines didn't seize (100% of the 2~% of total jobs done), while 4% of the 98% total jobs did seize... then priming has strictly speculate benefit... potential, but purely speculative, and is thus a distraction to the real issue, which I presume is oil starvation... reasons unknown)

Hundreds of oil filter housing gaskets changed with priming procedure and 0 losses, vs hundreds of housing gaskets changed without and I've personally seen/known of about 20-30 NG6 and NG8 engines.

so, its very important.

Originally Posted by JuniorB

I read that thread, still no evidence of how a gasket repair seizes a bearing. Looking at the housing itself, it’s all open ports but the thermostat,if you drain a tad bit of coolant to below the lower coolant port, it will eliminate any chance of any coolant entering the pan. If you drain the oil in the pan, you eliminate any dirty oil. Trying to fathom how the two are related to each other, is there anyone loosing an engine due to just an oil change?, motor or head work? I’ve done this same procedure on my n52, I let it run for a while before I drove it, that motor is an exact to a n54 as far as bottoms go, they all use the same bearings, housings, and oil pumps.

Yes cyl head or engine work (on a used engine) same scenario, same issue. N52 head replaced due to cam damage from a rocker coming apart.... engine locked up 12 miles down the road. priming procedure was NOT done. engine ran for nearly an hour on the lift while reassembling and buttoning it up. this was a few years ago before the priming procedure was released.

[THE BEAST]

Good to know Alex. Would you care to share the proper way to prime ?

[THE BEAST]

So I saw a bulletin on this procedure, I also read about a guy that lost his motor at the hands of the dealer. Same thing, OFHG properly primed, engine seized at the DEALERSHIP. Supposedly they admitted that it has happened before even after being properly primed. Interesting as many have done this repair WITHOUT priming and car runs fine.

[Magnusk77]

I just started my 135i after sitting for 7 months cold over the winter/fall. No priming done and it had a dead battery. Hooked up the jumper cables and boom started up no problem after a couple minutes. I think maybe quality oil is a suspect in this? Cheap oil may not hold enough film strength or something

[sparky1]

I've done my OFHG twice now on my car and had it down for ~1-2 weeks during this process and never even thought twice to prime the oil in the car.

Haven't had issues since either too.

[codesx]

Originally Posted by sparky1

I've done my OFHG twice now on my car and had it down for ~1-2 weeks during this process and never even thought twice to prime the oil in the car.

Haven't had issues since either too.

I've had mine off twice now, with the first being the better part of a winter. (all ports were plugged and had a plastic bag over if not working on them)
No issues either time.
Certainly not arrogant when I say this though.

I'll likely 'prime' the next time out of fear, and sadly not based on understanding the exact science on how not doing so will cause damage.
It would be awesome to have the root issue identified.

[sparky1]

There was actually a post recently on e90 post about cleaning the VANOS filters/checkvalves.

It would seem that should hold somewhat primed oil up in the head, so there wouldn't be a need to prime the motor, unless those drain after sitting for a certain amount of time.

They live right in the front of the head on the exhaust side infront of the cylinder 1 manifold runner

DIY: VANOS Check Valve Replacement

[johnscales]

Had my ofhg and vcg done at the same time yesterday. Done about 30 miles until now. No issues so far (N54 335i). I don't expect to have any issues in the near future but will certainly report back if I do as this thread concerns me. Was thinking about possible cause and it popped into my head that my car was driven about between 5 and 10 miles to my mechanic and the oil was pretty much at running temp (at least 80 - 90 anyways).
It's not been mentioned but am wondering if there is any commonality by the engines being cold before you guys did your ofhg change/walnut blast?
kamsolo didn't say but there was some delay in davidponi's swap out right?

[rkreimer10]

I do many ofhg and this is the first of hearing of this problem. I hope my post can help and put peoples minds at ease.

After I finish an ofhg I start then stop the car, then start the car and check for leaks and then shut off, then back out to driveway and shut off, then wash the engine and this procedure cycles the engine on/off a few times.

Never have I ever had a problem! Maybe this replicating the bleeding proceedure, but I would never let a car that just had the system opened to just leave or run without cycling the car on and off a few times.

Also, here is my dumbness to hope I settle some worry.

Working on my own car I was replacing a turbo oil return line. In the process I forgot to fill the motor before starting the car to check for leaks. After 30 seconds I realized there was no oil in the car and shut it off. I filled with oil & cycled the ignition a few times. This was 4000 miles ago and im still embarrassing other "fast" cars.....

[rkreimer10]

Another question that comes to my mind is......

How many of these people are WOT before the engine is in fact warmed up.

-customer picks up car from shop
-drives away and in 1 block goes wot
-man it feels good to have this beast back!
-spun bearing seizes a few miles later.

Maybe?

[Magnusk77]

Originally Posted by rkreimer10

Another question that comes to my mind is......

How many of these people are WOT before the engine is in fact warmed up.

-customer picks up car from shop
-drives away and in 1 block goes wot
-man it feels good to have this beast back!
-spun bearing seizes a few miles later.

Maybe?

Definitely possible. I generally don't even go above 3000ish rpm until it hits 80-90* C.