[CaioNotKyle]

Hey guys,

I popped my hood open yesterday and found dried coolant all over my alternator and oil filter housing. Seems like the oil filter housing/thermostat housing is leaking coolant? Trying to get some feedback before I open it up and replace the gasket inside. This is my first BMW so I am trying to get some opinions before I start taking things apart trying to fix this leak.

[rtl32]

That is one of the "will happen" failures that the n55 almost always experiences during its lifespan. I did mine at 50k because I started having oil gunk collect around the bottom plate from it.

You will need the gaskets, enough coolant for a full flush, and an oil change kit.

Oil and coolant flow through the housing. The gaskets are cheap on FCP euro and they even have a guide on how to replace it yourself. It's not difficult, but the intake manifold is a PITA because you have to loosen the whole thing to get to bolts on the back of the OFH assembly.

If you are planning on ever upgrading your HPFP to use more aggressive tunes and or ethanol, you will save yourself a lot of time and headache with the manifold by doing them together. Both jobs need the manifold to be moved (HPFP = off completely) so may as well do them together if the HPFP is going to happen anyway.

Best of luck. Make sure you properly bleed the coolant system by having the car go through its process (also look that up, really easy)

[Wolfman’s Brother]

OP What’s your mileage?

@rtl32 Which gaskets fail exactly?

[F87source]

Make sure you prime your oil system if you do gasket replacements on the oil filter housing otherwise you risk rod bearing failure or seizure.

[TheSandman_M2]

Shit, same thing just happened to me.

[XutvJet]

Perhaps I'm missing something, but I don't see any liquid anywhere in those photos. If you're talking in about the white residue on those aluminum parts, it's surface corrosion and nothing to worry about.

[F87source]

Originally Posted by XutvJet

Perhaps I'm missing something, but I don't see any liquid anywhere in those photos. If you're talking in about the white residue on those aluminum parts, it's surface corrosion and nothing to worry about.

The pock marks could very well be surface corrosion, but dried coolant looks whitish blushish just like those white spots. So it could be residual splatter. Probably pressure test the coolant system to get an affirmative answer before spending time doing a job that isn't needed.

You can also try to scape at the white marks, if it goes away it could be coolant residue, if it doesn't it is surface corrosion.

[Strandh]

Originally Posted by TheSandman_M2

Shit, same thing just happened to me.

Same here...
Have you found any guide for how to replace the gasket?
BR, Simon

[TheSandman_M2]

I think it's just surface corrosion like F87source said. I've ran it a few times now and haven't seen any fluid. I'll keep checking, my warranty is up in March.

[F87source]

Originally Posted by TheSandman_M2

I think it's just surface corrosion like F87source said. I've ran it a few times now and haven't seen any fluid. I'll keep checking, my warranty is up in March.

Xuv said it not me, you can pressure test the coolant loop with a cheap pressure tester to be sure.

[CaioNotKyle]

I checked with a local shop as well and they seem to also think its surface corrosion on the aluminum parts. My coolant level is still at the full line and there doesn't seem to be coolant build up around the cap or any plastic parts. I will probably do a coolant pressure test to double check. My mileage is at about 52,500. I appreciate the input from everyone though.

[F87source]

Originally Posted by CaioNotKyle

I checked with a local shop as well and they seem to also think its surface corrosion on the aluminum parts. My coolant level is still at the full line and there doesn't seem to be coolant build up around the cap or any plastic parts. I will probably do a coolant pressure test to double check. My mileage is at about 52,500. I appreciate the input from everyone though.

Yeah if you can't wipe it off with a wet rag then it is corrosion, like when I did a coolant flush a year or two ago it left a whitish blue residue just like that on my subframe when it was dry, but the difference is it wiped off and left no trace afterwards.

[XutvJet]

I think it would be rather odd to only have coolant on aluminum parts and nothing else. Coolant attracts dirt thus the surrounding plastics and other parts should also be covered in coolant. Lastly, about the only thing on the top of an N55 motor that's going to cause a coolant leak is the overflow hose to the overflow tank. And when those go, a large amount of coolant is puked.

[F87source]

Originally Posted by XutvJet

I think it would be rather odd to only have coolant on aluminum parts and nothing else. Coolant attracts dirt thus the surrounding plastics and other parts should also be covered in coolant. Lastly, about the only thing on the top of an N55 motor that's going to cause a coolant leak is the overflow hose to the overflow tank. And when those go, a large amount of coolant is puked.

True. But distribution pattern imo matches what would happen if a seal were to leak slowly - it is all over the aluminium OFH (primarily here because the casted aluminium parts have grooves and makes it easier for the coolant to pool and stay behind), and a bit on the verticle parts of the engine cover (smoother so harder for it to stay behind to leave residue).

[KevM2]

Originally Posted by F87source

Make sure you prime your oil system if you do gasket replacements on the oil filter housing otherwise you risk rod bearing failure or seizure.

Originally Posted by F87source

Make sure you prime your oil system if you do gasket replacements on the oil filter housing otherwise you risk rod bearing failure or seizure.

What do you mean by priming? Adding some oil into the filter and the filter housing itself? If so then sounds like this should also be done with any oil change which I haven't been doing

[F87source]

Originally Posted by KevM2

What do you mean by priming? Adding some oil into the filter and the filter housing itself? If so then sounds like this should also be done with any oil change which I haven't been doing

No, priming should only be done when you remove a component of the oiling system: OFH, oil cooler, vanos, turbo etc. This is because it introduces air pockets into the oil system and this can starve the bearings of oil resulting in wear and tear or even a siezed engine. To prevent this you would disconnect the injectors (bmw says to pull the LPFP fuse on the F series, they used to say pull the injectors but I think they switched to the LPFP fuse as it is easier to do, but personally I prefer to pull the injector harnesses so you don't flood the cylinders with gasoline and the HPFP is lubricated by gas so you probably don't want that to be pumping dry) then you crank the car for a period of time I think 15 seconds you will have to look at the tsb, then let it rest for 30 seconds so the starter doesn't over heat, and do this ~7 times. This will prime the oiling loop with oil so the engine doesn't starve of oil on the first start up after the repair. You should also have a battery charger attached and pull the spark plugs so it doesn't build compression and spins easier.


You don't need to prime your oiling loop for oil changes, and you don't really need to fill the oil filter housing with oil after oil filter changes either. You can, but I doubt it would do much to skip this step. But you should be careful because if you over fill and oil gets on your belt then you pretty much have to replace that belt, so it is a risky thing to do, especially since the oil drains out immediately as you fill it (due to the drainage hole bmw implemented which is normally plugged up by the oil filter lid, and if that is not in place oil drains out I explained this in depth in my malo industries oil filter cap review if you want to know more).

[///MPhatic]

Originally Posted by F87source

No, priming should only be done when you remove a component of the oiling system: OFH, oil cooler, vanos, turbo etc. This is because it introduces air pockets into the oil system and this can starve the bearings of oil resulting in wear and tear or even a siezed engine. To prevent this you would disconnect the injectors (bmw says to pull the LPFP fuse on the F series, they used to say pull the injectors but I think they switched to the LPFP fuse as it is easier to do, but personally I prefer to pull the injector harnesses so you don't flood the cylinders with gasoline and the HPFP is lubricated by gas so you probably don't want that to be pumping dry) then you crank the car for a period of time I think 15 seconds you will have to look at the tsb, then let it rest for 30 seconds so the starter doesn't over heat, and do this ~7 times. This will prime the oiling loop with oil so the engine doesn't starve of oil on the first start up after the repair. You should also have a battery charger attached and pull the spark plugs so it doesn't build compression and spins easier.


You don't need to prime your oiling loop for oil changes, and you don't really need to fill the oil filter housing with oil after oil filter changes either. You can, but I doubt it would do much to skip this step. But you should be careful because if you over fill and oil gets on your belt then you pretty much have to replace that belt, so it is a risky thing to do, especially since the oil drains out immediately as you fill it (due to the drainage hole bmw implemented which is normally plugged up by the oil filter lid, and if that is not in place oil drains out I explained this in depth in my malo industries oil filter cap review if you want to know more).

I recently became aware of the common oil filter gasket failures on previous N55's and started watching videos on replacing it. It's interesting that none of them show this priming step. Do people know this and just don't do it for whatever reason? I guess this is why it's so expensive to have it done at the dealer, they actually take the time to do all the steps.

My recently acquired car has just under 20,000 miles and is dry, but I'm keeping an eye on it. I had no idea of the catastrophic failure that could result from the common leak. I considered getting a Kies guard, but with how particular I am I think I'll just keep an eye on it.

[XutvJet]

Originally Posted by F87source

True. But distribution pattern imo matches what would happen if a seal were to leak slowly - it is all over the aluminium OFH (primarily here because the casted aluminium parts have grooves and makes it easier for the coolant to pool and stay behind), and a bit on the verticle parts of the engine cover (smoother so harder for it to stay behind to leave residue).

I hear ya, but I totally disagree. I've seen a number of photos of BMW motors on this site and many others showing aluminum corrosion like this on the aluminum OFH assembly, alternator, and tensioner. Plus, it coolant is covering all of these components, it would certainly all over the front of the engine, the belt, and lower tray.

With the exception of the $40 coolant return line which should be replaced at least every 5 years/50K miles on these cars, coolant leaks on N55s are extremely rare. I've never heard of the OFH assembly leaking coolant either. Oil is what leaks out due to the location of the oil galleys to the leading gasket edges.

[F87source]

Originally Posted by ///MPhatic

I recently became aware of the common oil filter gasket failures on previous N55's and started watching videos on replacing it. It's interesting that none of them show this priming step. Do people know this and just don't do it for whatever reason? I guess this is why it's so expensive to have it done at the dealer, they actually take the time to do all the steps.

My recently acquired car has just under 20,000 miles and is dry, but I'm keeping an eye on it. I had no idea of the catastrophic failure that could result from the common leak. I considered getting a Kies guard, but with how particular I am I think I'll just keep an eye on it.

I suspect the reason why people don't show that step is alot of them are unaware of the tsb that bmw posted about this. Alot of the youtube guys don't really know this engine indepth if I am being a bit harsh, they kind of just know how to tear it apart based on basic mechanical know how but not to the level of bmw's service specs. Alot of these youtube guys don't even replace TTY bolts, or torque to the proper spec. But again this is me being a little bit harsh because you can't expect every bmw owner to go above and beyond to the entusiast level.

20k miles isn't that old, you have alot longer before any issues were to arise. So take it easy no need to panic.

BTW I recomend the MALO crank seal guard over the kies plate, that's my personal preference and I talk about why on my review if you wanted to know my thinking process. But either way you probably should get a guard, they're pretty cheap insurance imo.

[///MPhatic]

Originally Posted by F87source

I suspect the reason why people don't show that step is alot of them are unaware of the tsb that bmw posted about this. Alot of the youtube guys don't really know this engine indepth if I am being a bit harsh, they kind of just know how to tear it apart based on basic mechanical know how but not to the level of bmw's service specs. Alot of these youtube guys don't even replace TTY bolts, or torque to the proper spec. But again this is me being a little bit harsh because you can't expect every bmw owner to go above and beyond to the entusiast level.

20k miles isn't that old, you have alot longer before any issues were to arise. So take it easy no need to panic.

BTW I recomend the MALO crank seal guard over the kies plate, that's my personal preference and I talk about why on my review if you wanted to know my thinking process. But either way you probably should get a guard, they're pretty cheap insurance imo.

Always wonderful responses from you. Thank you again!

[F87source]

Originally Posted by XutvJet

I hear ya, but I totally disagree. I've seen a number of photos of BMW motors on this site and many others showing aluminum corrosion like this on the aluminum OFH assembly, alternator, and tensioner. Plus, it coolant is covering all of these components, it would certainly all over the front of the engine, the belt, and lower tray.

With the exception of the $40 coolant return line which should be replaced at least every 5 years/50K miles on these cars, coolant leaks on N55s are extremely rare. I've never heard of the OFH assembly leaking coolant either. Oil is what leaks out due to the location of the oil galleys to the leading gasket edges.

Yeah I know what you're trying to say, and I guess when I read the initial post that they said dried coolant it implied that the OP knew that coolant was leaking and the expansion tank level was dropping too so there's that. OP didn't post pictures of anywhere else so yeah. But you are right generally it is oil that leaks out, but it could be a first and not technically impossible. Plus the whitish marks really does look like dried coolant.

It is always hard to diagnose issues on the internet with only partial bits of information.

[Strandh]

Originally Posted by F87source

No, priming should only be done when you remove a component of the oiling system: OFH, oil cooler, vanos, turbo etc. This is because it introduces air pockets into the oil system and this can starve the bearings of oil resulting in wear and tear or even a siezed engine. To prevent this you would disconnect the injectors (bmw says to pull the LPFP fuse on the F series, they used to say pull the injectors but I think they switched to the LPFP fuse as it is easier to do, but personally I prefer to pull the injector harnesses so you don't flood the cylinders with gasoline and the HPFP is lubricated by gas so you probably don't want that to be pumping dry) then you crank the car for a period of time I think 15 seconds you will have to look at the tsb, then let it rest for 30 seconds so the starter doesn't over heat, and do this ~7 times. This will prime the oiling loop with oil so the engine doesn't starve of oil on the first start up after the repair. You should also have a battery charger attached and pull the spark plugs so it doesn't build compression and spins easier.


You don't need to prime your oiling loop for oil changes, and you don't really need to fill the oil filter housing with oil after oil filter changes either. You can, but I doubt it would do much to skip this step. But you should be careful because if you over fill and oil gets on your belt then you pretty much have to replace that belt, so it is a risky thing to do, especially since the oil drains out immediately as you fill it (due to the drainage hole bmw implemented which is normally plugged up by the oil filter lid, and if that is not in place oil drains out I explained this in depth in my malo industries oil filter cap review if you want to know more).

Thanks for the information, news to me..
After priming is finished, do you trust the oil level measurement in the display or do you empty the system and refilling the correct amount?

I more or less only drive on track and have experienced when the measurement shows correct level I have filled in couple of dl, and the measurement will still show the same level.