[lwgrenier]

If I remember correctly at least four of my rod bearings showed signs of overheating/spinning when my motor went after OFHG change. I would think it would take a pretty big piece of debris to cause that. Also if it takes a lot of force to turn the motor wouldn't that indicate more than one bearing seized?

[TheMidnightNarwhal]

Originally Posted by lwgrenier

If I remember correctly at least four of my rod bearings showed signs of overheating/spinning when my motor went after OFHG change. I would think it would take a pretty big piece of debris to cause that. Also if it takes a lot of force to turn the motor wouldn't that indicate more than one bearing seized?

So then oil starvation?

[TheMidnightNarwhal]

Originally Posted by feuer

Yes, but there is a wax capsule that allows the spring to push the piston as temperature changes.

Does the cooler have a full close position or there is always a small ammount of oil flowing through it?

[lwgrenier]

Originally Posted by TheMidnightNarwhal

So then oil starvation?

Yeah. I'm not sure what the oil gallery looks like for the rod bearings but I would think a 2mm piece of debris shouldn't be able to plug the entire thing up.

[feuer]

Originally Posted by TheMidnightNarwhal

Does the cooler have a full close position or there is always a small ammount of oil flowing through it?

Oil always flow, or there will develop a leak quickly from the pressure.

[Nick_F]

Did mine about 2 months ago and didn't prime it. I just made sure to add oil to the housing after before putting the filter back in. No issues as of yet

[bbnks2]

Originally Posted by drwillb

Carguy138, the oil cooler thermostat is just like an old school water coolant thermostat. It's a metallic spring that expands and contracts in the specified temperature range and controls the oil flow passage with a metal piston that blocks the openings. The (movement of the piston) opening of the oil passages into and out of the oil cooler occurs slowly so that air can flow out slowly if there is an air bubble.

My car has the ER race oil coolers and I did not bleed them while hooking them back up to the thermostat. However, I've since replaced both coolers over the last 12 months and I have an urge to check to make sure there is no air trapped in them. Both the inlet and outlet fitting for these are at the bottom of the coolers and I'm not sure how the oil is routed through them but I can't see how they would self-bleed.

There is almost no way for air to get "trapped" in an oil cooler. There is science behind it. Paraphrasing for you a bit, it has something to do with the pressure and the viscosity of the oil. Air is naturally the first thing purged from the cooler/lines/galleys. Air trapped in an oil cooler wouldn't starve an engine of oil either.

The oil thermostat is always allowing some amount of oil to flow through the oil cooler. It is always pressurized and flowing. Aftermarket thermostats do the same thing.

This has also happened on cars with no oil cooler (even N52's), aftermarket oil coolers, and stock oil coolers, so, it doesn't really add up that the oil cooler would have anything to do with this.

Air pocket or oil delivery issue in general doesn't make much sense either since he primed the system and filled the filter housing prior to driving. Oil pump is a positive displacement pump. So long as there is oil at the pickup tube (in the oil pan) the pump is going to deliver oil to the oil filter housing.

He said he had to scrape off old gasket material. Is it possible he scratched the surface? dropped some aluminum shavings into the galley?

You don't need to clog the entire oil galley to spin a rod bearing either. The rods are fed oil from the main bearings. Oil is fed into the main bearings from oiling holes in the block. There is a groove in the center of the main bearings that allows most of the oil pressure to bypass the main bearings and feed a hole in the crankshaft. The crankshaft then carries the oil to the rod journal and lubricates the rod bearings. A clog in the main bearing groove would cut off the supply of oil to the rod bearing for that journal. If the material is small enough to make it through the main bearing groove then it would be carried to the journal surface of the rod bearing directly where you now only have .0015" to .0018" clearance. Even a few grits of sand would be enough to score the surface and/or jam up in the rod bearing journal. Even if the bearing is able to absorb the damage, the surface is now mauled up and oil flow regime properties change.

Some cars seem to seize instantly and others go several thousand miles.

[drwillb]

Originally Posted by bbnks2

There is almost no way for air to get "trapped" in an oil cooler. There is science behind it. Paraphrasing for you a bit, it has something to do with the pressure and the viscosity of the oil. Air is naturally the first thing purged from the cooler/lines/galleys. Air trapped in an oil cooler wouldn't starve an engine of oil either.

The oil thermostat is always allowing some amount of oil to flow through the oil cooler. It is always pressurized and flowing. Aftermarket thermostats do the same thing.

This has also happened on cars with no oil cooler (even N52's), aftermarket oil coolers, and stock oil coolers, so, it doesn't really add up that the oil cooler would have anything to do with this.

Air pocket or oil delivery issue in general doesn't make much sense either since he primed the system and filled the filter housing prior to driving. Oil pump is a positive displacement pump. So long as there is oil at the pickup tube (in the oil pan) the pump is going to deliver oil to the oil filter housing.

He said he had to scrape off old gasket material. Is it possible he scratched the surface? dropped some aluminum shavings into the galley?

You don't need to clog the entire oil galley to spin a rod bearing either. The rods are fed oil from the main bearings. Oil is fed into the main bearings from oiling holes in the block. There is a groove in the center of the main bearings that allows most of the oil pressure to bypass the main bearings and feed a hole in the crankshaft. The crankshaft then carries the oil to the rod journal and lubricates the rod bearings. A clog in the main bearing groove would cut off the supply of oil to the rod bearing for that journal. If the material is small enough to make it through the main bearing groove then it would be carried to the journal surface of the rod bearing directly where you now only have .0015" to .0018" clearance. Even a few grits of sand would be enough to score the surface and/or jam up in the rod bearing journal. Even if the bearing is able to absorb the damage, the surface is now mauled up and oil flow regime properties change.

Some cars seem to seize instantly and others go several thousand miles.

+1 for debris in the system

I mentioned air in my oil coolers because I have the ER race setup and both the inlet and outlet for oil are next to each other at the bottom of the cooler. I just don't see how an air bubble can be pushed out with this geometry.

[bbnks2]

Originally Posted by drwillb

+1 for debris in the system

I mentioned air in my oil coolers because I have the ER race setup and both the inlet and outlet for oil are next to each other at the bottom of the cooler. I just don't see how an air bubble can be pushed out with this geometry.

Orientation does not matter. Google around and you'll find plenty of articles explaining why inlet/outlet orientation does not matter for anything other than ease of draining.

[drwillb]

Originally Posted by bbnks2

Orientation does not matter. Google around and you'll find plenty of articles explaining why inlet/outlet orientation does not matter for anything other than ease of draining.

I couldn't find any clear articles/posts on the self-bleeding of the style oil cooler that ER uses, but I did find this picture of an ER installation. Yeah, it clearly shows that oil will flow across the cooler vertically and horizontally, thereby self-bleeding. Especially if the thermostat opens slowly.

Thanks for pushing me, bbnks2.

[9krpmrx8]

[drwillb]

Originally Posted by 9krpmrx8

No kidding.

It’s an ER kit so I went with their setup. Besides flow the other big problem is the hose connections hanging down. I was rolling very slowly through a parking lot on a rainy day a year ago and dropped a wheel into an invisible pothole. It was deep enough that the cooler hoses impacted the ground and one of the welds cracked. I didn’t know this had happened until I got on the highway and the big red oil dash light came on.

Did you know that you can’t turn the engine off while the car is moving? Yeah, I found that out at that moment.

Sorry for thread jacking.

[TheMidnightNarwhal]

So OP will you have to chance to be able to take the bottom end out to see rod bearings or no?

[feuer]

Originally Posted by drwillb

Did you know that you can’t turn the engine off while the car is moving? Yeah, I found that out at that moment.

Yes you can, press start/stop engine button and hold it pressed.

[pete_gpx]

Originally Posted by TheMidnightNarwhal

So OP will you have to chance to be able to take the bottom end out to see rod bearings or no?

I'm shifting to a new house in a couple of weeks. Once there, I'll start pulling the motor out and will pull off the oil pan to check out what went wrong.

[delmarco]

Originally Posted by pete_gpx

Well, really feel like I'm part of a statistic at this point.

Anyway, thought I'd post up to lend my voice to say; there is something wrong with these early E series N55s. If you own one, I recommend having your OFHG replaced at a reputable workshop that has insurance to cover any possible failures thereafter.

I predicted more of these failures and got tarred and feathered by some of the haters in here.


Sorry for your loss.

I only wished the idiots in here who are always posting, prodding and hating in every thread took me more seriously at the time and supported my warning that DIY'ing your N55 E9x car was a huge gamble that could lead to engine destruction.

Even with statistics showing failure is rare whether you play Russian Roulette with one bullet in your gun or 5 bullets you can still blow your head off.

[Ozzie335i]

Pete, do you have an oil cooler?

[Welcome to NBA Jam]

Originally Posted by delmarco

Even with statistics showing failure is rare whether you play Russian Roulette with one bullet in your gun or 5 bullets you can still blow your head off.

Except the probability of catastrophic failure is significantly lower than 16.7% and 83.3%.

This is like playing Russian Roulette with a 100 bullet chamber, at worst. Blanket staying you shouldn't DIY anything on an N55 is silly. Count the number of people who aren't experiencing engine failure after this job. It's hard because they're not posting a new thread that they did it without any issues.

[delmarco]

Originally Posted by Welcome to NBA Jam

Except the probability of catastrophic failure is significantly lower than 16.7% and 83.3%.

This is like playing Russian Roulette with a 100 bullet chamber, at worst. Blanket staying you shouldn't DIY anything on an N55 is silly. Count the number of people who aren't experiencing engine failure after this job. It's hard because they're not posting a new thread that they did it without any issues.

I've been DIY'ing everything on my BMWs since 2004 so I would NEVER make a statement to not-DIY your own car. In fact the much appreciated success of my YouTube Channels has relied on encouraging young and novice BMW drivers wanting to DIY both simple and complicated things with regards to these awesome cars! So you are wrong there. Not your fault though. You just met me.

Now with pleasantries out the way, I would NEVER tell someone to DIY their OFHG when there is even the 0.00000001 chance that if EVERYTHING IS DONE PROPERLY their engine could explode right after for no apparent reason.

What you kids dont seem to understand about the grown up world is that we grown ups are terrified of the unknown. Something unexpected happens where lives are lost or property gets damaged and the experts don't know why it happened reason dictates we find that out before trying to do it again.

This is why Boeing grounded 800+ planes and halted manufacturing on over a billion dollars worth of planes BECAUSE 2 planes mysteriously crashed. Two Planes! Not three not four! Two Planes bruh!

This is why the ENTIRE planet is scared to death of a rather basic respiratory virus that has killed less people than catching frostbite. Because we DO NOT KNOW what it is and how effectively it spreads!

So my friend it is the unknown here that makes me advise to do any OFHG at the BMW Dealership or a shop with good liability insurance. At least UNTIL WE ALL UNDERSTAND WHY IT IS HAPPENING! Which, if we are as smart and awesome as we think we are, should be soon. right?

[TheGoodTheBadTheUgly]

I understand your point of view but keep in mind that a lot of these seized engine seize up after driving around a bit after the job has been done.

There are some cases where dealerships replaced the OFHG and that they lent back the car to the customer, which eventually seized on the way back home has occurred. If your car wasn't under warranty, I don't know how you could manage to get the dealership to give you another engine and on top of that you payed over 1K for this stupid job.

Another reason why it is not necessarily that worth it to get it done in a dealership.

[9krpmrx8]

Science,

[Ozzie335i]

"Two Planes! Not three not four! Two Planes bruh!"

I'd have to go on record as saying that having two planes going down due to this defect is my threshold for halting production. Boeing decided to do this on the cheap, and it bit them.

I asked a guy on N54 that recently had an OFHG failure if he had an oil cooler. Just putting out the possibility that somehow the engines lose prime due to that.