[Itogliano]

Forgive me if this is a dumb question but I just went through the process of replacing my OFHG gasket this weekend (along with a couple other minor things), and the last two things I did before starting the car was to bleed the coolant system, and to prime the oil pump. This was also the first time I've changed fluids myself.

This had me wondering, is it necessary to prime the oil pump every time you do an oil change? I haven't been able to find a clear answer anywhere. My initial thought was, "no," but why would the OFHG be a special case? In both cases you're fully draining the oil out, so isn't the system dry regardless if the OFH is removed or not?

[Billfitz]

No. I'm not so sure that you really need to do so after the gasket change. The coolant must be bled, but my repair manual doesn't say anything about the oil.

[Itogliano]

I came across mixed feelings about whether it was needed or not so I figured better safe than sorry. It took all of 5 minutes to disconnect the fuel injectors. Good to know I don't have to do it after every change though

[Itogliano]

Here's the SIB from BMW (last paragraph under INFORMATION) saying it needs/should be done after removing OFH (and other cases).

https://static.nhtsa.gov/odi/tsbs/20...51166-9999.pdf

[Billfitz]

IMO that's overkill. Before installing the filter I'd fill the oil filter housing with oil, then put the rest in via the oil filler cap. My guess is that there were mechanics who weren't doing that, so they put this in place as a CYA measure...BMWs ass, that is. Then if the mechanic failed to do it and there was a problem it would be the mechanic's to deal with.

[Itogliano]

I can certainly believe that. Yeah, I poured about 750ml directly into the housing and filled the rest using the normal fill location.

[edycol]

Absolutely prime it on units with oil cooler! Pouring oil down OFH won't help with air in oil cooler lines. When one starts cranking, oil still flows through oil cooler lines regardless that thermostat is in "closed" position. There is still small amount of oil flow to keep oil temperature between engine and cooler equal.

[Itogliano]

Originally Posted by edycol

Absolutely prime it on units with oil cooler!.

Are you talking about anytime the OFH is removed/oil cooler lines are disconnected, or after every oil change?

[edycol]

Originally Posted by Itogliano

Are you talking about anytime the OFH is removed/oil cooler lines are disconnected, or after every oil change?

After OFH is removed and lines disconnected. Cranking engine puts oil pump in high pressure mode. That gets rid of any air gaps, and fills lines and oil cooler with oil. Idling is putting pump in efficiency mode and air is potential (probably) present.
Changing oil doesn't require priming procedure.

[cubeee]

Sorry to bring up an old thread .....
Although the BMW SI B11 09 15 talks about the need to prime the oil system after things like removal of oil filter housing (eg gasket change), it doesn't talk about why, and those details about the oil pump mode while cranking vs started/ on idle.

Is there any other documentation on this?

Thanks.

[F32Fleet]

Originally Posted by cubeee

Sorry to bring up an old thread .....
Although the BMW SI B11 09 15 talks about the need to prime the oil system after things like removal of oil filter housing (eg gasket change), it doesn't talk about why, and those details about the oil pump mode while cranking vs started/ on idle.

Is there any other documentation on this?

Thanks.

Bearings are starved of oil for too long. This causes accelerated wear which can, at a later time , result in bearing failure.

[cubeee]

Thanks. I'm interested because I had my OFHG/ oil/ oil filter done on my N55 and 150 miles later my engine is knocking and has metal in the oil filter. The garage that did it doesn't think it's anything to do with them. Engine sounded fine before and has less than 80k miles on it.

[thejeremyman9]

Originally Posted by cubeee

Thanks. I'm interested because I had my OFHG/ oil/ oil filter done on my N55 and 150 miles later my engine is knocking and has metal in the oil filter. The garage that did it doesn't think it's anything to do with them. Engine sounded fine before and has less than 80k miles on it.

Sounds exactly like failure to prime the oil system, but proving causation/fault may be difficult

[F32Fleet]

Originally Posted by thejeremyman9

Sounds exactly like failure to prime the oil system, but proving causation/fault may be difficult

Originally Posted by cubeee

Thanks. I'm interested because I had my OFHG/ oil/ oil filter done on my N55 and 150 miles later my engine is knocking and has metal in the oil filter. The garage that did it doesn't think it's anything to do with them. Engine sounded fine before and has less than 80k miles on it.

That's how it would go down. Iirc the impetuous was BMW seeing warranty claims resulting from OFHG repairs performed at dealerships.

[lidation]

I finished my Oil filter housing gasket change and today I tried to "prime" the engine according to this service bulletin. https://static.nhtsa.gov/odi/tsbs/20...51166-9999.pdf

However, even though I unplug the fuel pump fuses (fuse #139 and fuse #184, both in the trunk passenger side), my car still started up and running. I quickly stopped the car. Why is this? I thought once the fuel pump fuses are disconnected, the engine will just crank and not start right? Now what?

[lidation]

Originally Posted by lidation

I finished my Oil filter housing gasket change and today I tried to "prime" the engine according to this service bulletin. https://static.nhtsa.gov/odi/tsbs/20...51166-9999.pdf

However, even though I unplug the fuel pump fuses (fuse #139 and fuse #184, both in the trunk passenger side), my car still started up and running. I quickly stopped the car. Why is this? I thought once the fuel pump fuses are disconnected, the engine will just crank and not start right? Now what?

Update: anyway, I just fire up the engine, let me idle for a few minutes and drove slowly for a couple of miles without issues. Then I drive another half an hour at varying speeds and RPM. The car drives and sounds fine. The priming probably isn't needed.

[F32Fleet]

Originally Posted by lidation

Update: anyway, I just fire up the engine, let me idle for a few minutes and drove slowly for a couple of miles without issues. Then I drive another half an hour at varying speeds and RPM. The car drives and sounds fine. The priming probably isn't needed.

Failure, if it occurs, isn't always immediate.

[thejeremyman9]

Originally Posted by lidation

Update: anyway, I just fire up the engine, let me idle for a few minutes and drove slowly for a couple of miles without issues. Then I drive another half an hour at varying speeds and RPM. The car drives and sounds fine. The priming probably isn't needed.

Originally Posted by F32Fleet

Failure, if it occurs, isn't always immediate.

Exactly this. You could have just damaged the bearings/caused excessive wear and in the near future they will fail. The TSB doesnt exist for no reason.

Did you monitor your oil pressure on initial startup and see how long it took to build?

[lidation]

Originally Posted by thejeremyman9

Exactly this. You could have just damaged the bearings/caused excessive wear and in the near future they will fail. The TSB doesnt exist for no reason.

Did you monitor your oil pressure on initial startup and see how long it took to build?

Nope I did not monitor the oil pressure.

Again, my intention WAS to prime the engine by unplugging fuse #139 and #184 (fuel pump fuses). But so how the engine started up. So do you have any advice for other people who want to prime their engine? I was just following what the TSB said.

[AlmondJayRoM3]

Originally Posted by lidation

Nope I did not monitor the oil pressure.

Again, my intention WAS to prime the engine by unplugging fuse #139 and #184 (fuel pump fuses). But so how the engine started up. So do you have any advice for other people who want to prime their engine? I was just following what the TSB said.

If you remove the fuses you will still have residual pressure in the lines. It will take 10-20 seconds for the engine to stall out. Maybe remove the fuses and run it dead before doing the work.