[M2guru]

Originally Posted by F87source

You'd probably have to drain the oil cooler.

The oil pressure reading comes from the oil pressure sensor on the OFH.

I am about to do a test of the oil pressure by draining the fluid and watching the oil pressure. It made me think...what am I checking for? Is the "problem" with low pressure upon startup after removing something from the oil system or is it with air in the system. If it's air in the system, I am thinking that I won't see that in the oil pressure reading (maybe a blip), but I could be wrong. Thoughts on this? Wondering how to test it to get good information from the test.

[F87source]

Originally Posted by M2guru

I am about to do a test of the oil pressure by draining the fluid and watching the oil pressure. It made me think...what am I checking for? Is the "problem" with low pressure upon startup after removing something from the oil system or is it with air in the system. If it's air in the system, I am thinking that I won't see that in the oil pressure reading (maybe a blip), but I could be wrong. Thoughts on this? Wondering how to test it to get good information from the test.

Are you just going to start the car after draining the oil cooler? Because that would be really bad for the car. Or are you going to start the car after priming?

If you're starting without priming I would log oil pressure a few times starting the car as normal. Then I would log the oil pressure after work on the oil system.

If you want to see the results of priming, then log priming the oil system without draining the loop then log priming after draining the oil loop.


We are seeing if there is a drop in oil pressure and for how long due to air pockets.

[M2guru]

Originally Posted by F87source

Are you just going to start the car after draining the oil cooler? Because that would be really bad for the car. Or are you going to start the car after priming?

If you're starting without priming I would log oil pressure a few times starting the car as normal. Then I would log the oil pressure after work on the oil system.

If you want to see the results of priming, then log priming the oil system without draining the loop then log priming after draining the oil loop.


We are seeing if there is a drop in oil pressure and for how long due to air pockets.

I was going to: 1) drain the oil cooler, 2) prime without removing plugs and monitor oil pressure, 3) drain the oil cooler, 4) prime with plugs removed and monitor oil pressure. What I am wondering about is if I'll see a difference in oil pressure if the only thing priming does is remove air pockets. What I would like to understand is if there is a benefit to removing the plugs and, if so, what is the benefit. I am concerned I'll waste my time if it's only removing the air pockets...I think it'll do that with or without plugs. The speed or ease at which it cranks without plugs will not have an impact on the after-priming oil pressure. It is likely to get up to pressure more quickly because it's easier for the engine to turn over, but I think that might be what we're trying to avoid so turning over slowing might be better? I just want to make sure I am doing the right testing because I am not likely to do it another time... I have the bumper off and am awaiting shipment of the d088 oil cooler.

[ZM2]

Originally Posted by M2guru

I was going to: 1) drain the oil cooler, 2) prime without removing plugs and monitor oil pressure, 3) drain the oil cooler, 4) prime with plugs removed and monitor oil pressure. What I am wondering about is if I'll see a difference in oil pressure if the only thing priming does is remove air pockets. What I would like to understand is if there is a benefit to removing the plugs and, if so, what is the benefit. I am concerned I'll waste my time if it's only removing the air pockets...I think it'll do that with or without plugs. The speed or ease at which it cranks without plugs will not have an impact on the after-priming oil pressure. It is likely to get up to pressure more quickly because it's easier for the engine to turn over, but I think that might be what we're trying to avoid so turning over slowing might be better? I just want to make sure I am doing the right testing because I am not likely to do it another time... I have the bumper off and am awaiting shipment of the d088 oil cooler.

My do88 oil cooler took three weeks to arrive from Europe, so hopefully they stocked some up stateside for you. If not, hopefully you don’t need your car for a bit!

[M2guru]

Originally Posted by ZM2

My do88 oil cooler took three weeks to arrive from Europe, so hopefully they stocked some up stateside for you. If not, hopefully you don’t need your car for a bit!

Thanks for the info. I’ll be patient for a few more days until I get a timeframe then I guess I’ll have to put the bumper back on for the next event.

[F87source]

Originally Posted by M2guru

I was going to: 1) drain the oil cooler, 2) prime without removing plugs and monitor oil pressure, 3) drain the oil cooler, 4) prime with plugs removed and monitor oil pressure. What I am wondering about is if I'll see a difference in oil pressure if the only thing priming does is remove air pockets. What I would like to understand is if there is a benefit to removing the plugs and, if so, what is the benefit. I am concerned I'll waste my time if it's only removing the air pockets...I think it'll do that with or without plugs. The speed or ease at which it cranks without plugs will not have an impact on the after-priming oil pressure. It is likely to get up to pressure more quickly because it's easier for the engine to turn over, but I think that might be what we're trying to avoid so turning over slowing might be better? I just want to make sure I am doing the right testing because I am not likely to do it another time... I have the bumper off and am awaiting shipment of the d088 oil cooler.

Depending on your battery's health, how strong your starter is, your engine's resistance etc. You will either see oil pressure build faster with the plugs out, or in the worst case scenario you will not see any pressure build up with the plugs still in place - because that's what some guys on facebook have reported. Because spark plugs being in place allows the engine to build compression and that compression offers alot of turning resistance and thereby lowers oil pressure to the point where it cannot properly prime the engine.

[M2guru]

Originally Posted by F87source

Depending on your battery's health, how strong your starter is, your engine's resistance etc. You will either see oil pressure build faster with the plugs out, or in the worst case scenario you will not see any pressure build up with the plugs still in place - because that's what some guys on facebook have reported. Because spark plugs being in place allows the engine to build compression and that compression offers alot of turning resistance and thereby lowers oil pressure to the point where it cannot properly prime the engine.

There are certainly a number of variables - as you pointed out. I'll include information about battery health (less than a year old) and starter health (5 years and 30,000 miles old with no auto-restart) for reference when I report the test results.

What I was hoping to understand is if it's a matter of getting the air out of the system before the engine spins at idle speed or if it's a matter of building a certain amount of pressure. If it's air in the system, it seems more important to have a certain number of revolutions of the engine (and thus oil pump) to pump the air out rather than achieving a certain psi. If that's the case, it might be a matter of the number of revolutions vs. the speed at which the engine turns over. In other words, with plugs, you may have to crank an extra button push or two to get the same number of engine revolutions when compared to the remove-plugs version which would spin more revolutions per minute without the plugs.

From your facebook experience, are most issues after OFH gasket replacement or oil cooler replacement (or something else). I'd guess OFH because that's a more popular N55 procedure. I don't think I'll be messing with that and I'll just drain the oil cooler, so this may not be ideal test, but it'll be close.

[M2guru]

Here are the results from the test:

[F87source]

Originally Posted by M2guru

Here are the results from the test:

Thanks for the data!

Ok so here's what I'm seeing, 35 extra rpm with the plugs out. Now that does sound alot but it bought you 2.2 psi of extra oil pressure (40.9 psi vs 38.7 psi). That's not an insignificant amount of pressure, that's actually a 5.68% increase in peak pressure which is substantial and may be the difference in pushing out those last pockets of air.

If you could post the logs we could also look at area under the curve and see which situation gives you more pressure over time.

[samsamdar]

Just wanted to contribute and say that I recently did the OFHG and primed the car with 3 cranks (with the plugs still in) and had zero issues. I made sure to check the oil filter before plugging the LPFP back in and it was absolutely SOAKED prior to its first real startup. I made sure the filter and its housing cylinder were completely dry (didn't pour any oil into the OFHG) so I'm 100% sure that oil made it up there with zero issues while the plugs were still in.

[F87source]

Originally Posted by samsamdar

Just wanted to contribute and say that I recently did the OFHG and primed the car with 3 cranks (with the plugs still in) and had zero issues. I made sure to check the oil filter before plugging the LPFP back in and it was absolutely SOAKED prior to its first real startup. I made sure the filter and its housing cylinder were completely dry (didn't pour any oil into the OFHG) so I'm 100% sure that oil made it up there with zero issues while the plugs were still in.

That's good to hear!

[M2guru]

If 28psi is normal idle oil pressure:

Normal start up (after the car sat for a week): It took ~0.5 seconds to build up to ~900 rpms (higher than the subsequent tests). It took ~ 1 second to get to ~28psi. The average engine speed over that 1 second is 913. 913 revs per minute = 15.2 revs per second. If I did my math right, that's ~15.2 revolutions with oil pressure below ~28.

Normal start up log: https://www.bootmod3.net/log?id=64de...0b439c89d6a4d6

Startup after oil drain without spark plugs: It took .5 seconds to go from zero to 235 rpms. It took ~2.5 seconds to build up to ~28 psi. The average engine speed over those 2.5 seconds is 243 rpms. If I did my math right, that's 10 revolutions with oil pressure below ~28.

Without spark plugs log: https://www.bootmod3.net/log?id=64de...729b43b38a162d



Startup after oil drain with spark plugs: (I reran this test because of residual fuel during the original test). It took .5 seconds to go from zero to 235 rpms. It took ~6 seconds to build up to ~28psi. The average engine speed over those 6 seconds was 230. If I did my math right, that's 23 revolutions with oil pressure below ~28.

During this re-test, I noticed two things: 1) the car sat overnight and that seemed to impact the time needed to build pressure and 2) the second crank didn't seem to add any significant oil pressure. Perhaps it's recommended as insurance...

With plugs: https://www.bootmod3.net/log?id=64df...729b43b38a688e



Revised video:

[TheHunterHofman]

This is useful and valuable data, thank you for this.

[F87source]

Originally Posted by M2guru

If 28psi is normal idle oil pressure:

Normal start up (after the car sat for a week): It took ~0.5 seconds to build up to ~900 rpms (higher than the subsequent tests). It took ~ 1 second to get to ~28psi. The average engine speed over that 1 second is 913. 913 revs per minute = 15.2 revs per second. If I did my math right, that's ~15.2 revolutions with oil pressure below ~28.

Normal start up log: https://www.bootmod3.net/log?id=64de...0b439c89d6a4d6

Startup after oil drain without spark plugs: It took .5 seconds to go from zero to 235 rpms. It took ~2.5 seconds to build up to ~28 psi. The average engine speed over those 2.5 seconds is 243 rpms. If I did my math right, that's 10 revolutions with oil pressure below ~28.

Without spark plugs log: https://www.bootmod3.net/log?id=64de...729b43b38a162d

Attachment 3256149

Startup after oil drain with spark plugs: (I reran this test because of residual fuel during the original test). It took .5 seconds to go from zero to 235 rpms. It took ~6 seconds to build up to ~28psi. The average engine speed over those 6 seconds was 230. If I did my math right, that's 23 revolutions with oil pressure below ~28.

During this re-test, I noticed two things: 1) the car sat overnight and that seemed to impact the time needed to build pressure and 2) the second crank didn't seem to add any significant oil pressure. Perhaps it's recommended as insurance...

With plugs: https://www.bootmod3.net/log?id=64df...729b43b38a688e

Attachment 3256146

Revised video:

Good stuff!

Personally I still recommend pulling the plugs though, 2.2 extra psi of leak pressure and less cranks to get pressure. It's easier on your starter motor. Then you can crank it longer and harder.

[M2guru]

Full disclosure here: About a week ago I was at the track after changing the oil cooler and thermostat housing (all the video and information above). It was my fourth track day since changing oil and doing that work. Half way through the fourth day, my car lost a lot of power. Long story short, it's the stock turbo journal bearing(s) that got chewed up. Left a decent amount of glitter in the oil. It appears not much of the glitter made it up to the oil filter because it looks pretty clean.

So...the question is...did the oil priming process above not work? We can all see the pressure build. The one thing that I didn't do is prime it for three cycles - I was looking at oil pressure and not considering air bubbles...if that's even a thing or not. Or did something else happen?

For details of what happened, check this out: https://f87.bimmerpost.com/forums/sh....php?t=2053797

Happy to hear others thoughts on what the cause could be. Also, happy to hear thoughts about where to go from here...just flush the engine with oil...pull oil pan and inspect rod and crank bearings...other ideas?

Thanks in advance!

[AmuroRay]

Originally Posted by M2guru

Full disclosure here: About a week ago I was at the track after changing the oil cooler and thermostat housing (all the video and information above). It was my fourth track day since changing oil and doing that work. Half way through the fourth day, my car lost a lot of power. Long story short, it's the stock turbo journal bearing(s) that got chewed up. Left a decent amount of glitter in the oil. It appears not much of the glitter made it up to the oil filter because it looks pretty clean.

So...the question is...did the oil priming process above not work? We can all see the pressure build. The one thing that I didn't do is prime it for three cycles - I was looking at oil pressure and not considering air bubbles...if that's even a thing or not. Or did something else happen?

For details of what happened, check this out: https://f87.bimmerpost.com/forums/sh....php?t=2053797

Happy to hear others thoughts on what the cause could be. Also, happy to hear thoughts about where to go from here...just flush the engine with oil...pull oil pan and inspect rod and crank bearings...other ideas?

Thanks in advance!

First, what are your goals?
Second, if you're doing the labor yourself (and honestly, even if you aren't) I think it's a good ideal to make sure no additional shavings found their way into the bottom end of the engine.

[M2guru]

Originally Posted by AmuroRay

First, what are your goals?
Second, if you're doing the labor yourself (and honestly, even if you aren't) I think it's a good ideal to make sure no additional shavings found their way into the bottom end of the engine.

My goal is to not spend more money than I have to. Ideally, I'd not have had this problem. Tires, brakes, gas, and event fees are enough. Since I have to replace the turbo apparently, I'd like to go with something similar to stock or, if marginally more expensive, a bit of an upgrade (looking at Pure 500 right now). But I don't think that matters relative to the engine and bearings - not thinking of upgrading the rods and pistons. Just looking to do the right thing with the engine.

If it's not likely that I can flush the engine with fresh oil to rid it of the glitter, then I guess have to pull it apart. I don't have enough experience to know if that's even possible. The filter is clean enough to make me think that glitter didn't make it past the oil pan and filter.

[F87source]

Originally Posted by M2guru

Full disclosure here: About a week ago I was at the track after changing the oil cooler and thermostat housing (all the video and information above). It was my fourth track day since changing oil and doing that work. Half way through the fourth day, my car lost a lot of power. Long story short, it's the stock turbo journal bearing(s) that got chewed up. Left a decent amount of glitter in the oil. It appears not much of the glitter made it up to the oil filter because it looks pretty clean.

So...the question is...did the oil priming process above not work? We can all see the pressure build. The one thing that I didn't do is prime it for three cycles - I was looking at oil pressure and not considering air bubbles...if that's even a thing or not. Or did something else happen?

For details of what happened, check this out: https://f87.bimmerpost.com/forums/sh....php?t=2053797

Happy to hear others thoughts on what the cause could be. Also, happy to hear thoughts about where to go from here...just flush the engine with oil...pull oil pan and inspect rod and crank bearings...other ideas?

Thanks in advance!

It could possibly be from a bad purge - since you really should be the 3 cycles bmw specfies at the bare minimum if not alot more extra cycles in order to fully remove air pockets. But it could also be pushing the turbo really hard on a tuned car on the track.


You can't really expect the main bearings without removing the bed plate and crank shaft, you can only inspect the rod bearings with the oil pan removed. IMO it should be ok with just a flush of the oil pan, and monitoring UOA's.