[Tommeh]

2008 BMW 135i N54 engine with 95,000 miles. Issues with misfires on multiple cylinders (Number 3 and 4). New step colder plug gaped to .022" put in at 89k miles. Original coils, except #6 I replaced at 84k.... Never had intake valves cleaned...



Pulled spark plug #2,3, and 4 and switch cylinders #2 and #4 plug along with the coils. Haven't started to see if misfire switches from cylinder #4 to #2 because i checked my coolant, fingered the reservoir, and looks like my ol' girl has influenza....



Last year I had the thermostat and water pump replaced by an indie shop, and while getting new free OEM turbos BMW Orlando replaced the oil filer housing gasket and told me they did not need to replace any oil or coolant. So i don't know if BMW or the indie shop might have messed something up, but I need to get it fixed. Don't know the best course of action for fixing my coolant/oil mixture.

[135Pats]

Tough to say. Obviously you never want to see that much contamination, but I’ve seen trace amounts of oil in the coolant expansion tank and my motor is sound as a pound. I’ve never seen an amount that discolored it, though, just a few oily specs if you really focus with a flashlight.

The plugs look OK to me. No evidence of fouling or oil on the business end, which is what matters. If you smoked a ringland, you’d have a nasty idle and the electrode would be covered in oil.

[Tommeh]

Hmmmm. So I am I think I am going to flush my coolant... And check it periodically over the weeks. If The oil is continuing to mix I would imagine it could be a number of things... Would BMW warrenty diagnoses on the OHFG that they replaced?

[tc535i]

looks like head gasket or cracked head to me, I'd pressure test the cooling system if I were you

[Tommeh]

Originally Posted by tc535i

looks like head gasket or cracked head to me, I'd pressure test the cooling system if I were you

Don't like that answer. I would like to think something went wrong on OEM turbo replacement, water pump/temp replacement, or oil filer housing gasket replacement all of which happened 5-8k miles ago. If my head was going wouldn't I have seen more oil/coolant on my plugs that I just checked today?

I did just replace my oil as well... Would overfilling cause oil to mix with the coolant somehow?

[tc535i]

sorry, I thought this just showed up. the oil has been there since the repair?

[Tommeh]

No I changed the oil just last week at 94,400k miles and previously at 89k miles which was 2k after most of these repairs.

I might be over reacting but I feel like I only drained around 5.5-6qts of oil before I replaced last week. Would having around 1 extra qt cause any of these symptoms?

[tc535i]

no, but it could explain where the extra quart from the last change went

[tc535i]

extra oil would get burned off, the danger is the higher crankcase oil level could cause a froth as the crankshaft rotates, and frothy oil doesn't lubricate as well so you could get premature cylinder wall wear

coolant and oil are totally separate systems tho

[135Pats]

Originally Posted by tc535i

looks like head gasket or cracked head to me, I'd pressure test the cooling system if I were you

Originally Posted by Tommeh

don't like that answer. I would like to think something went wrong on OEM turbo replacement, water pump/temp replacement, or oil filer housing gasket replacement all of which happened 5-8k miles ago.

If you cracked the head you’d have a serious loss of pressure integrity and compression. The car would be near undriveable, though boosted motors can create some compression under load so maybe if it was a microscopic type crack, you wouldn’t notice it. Regardless I strongly doubt that’s the issue.

Shot head gasket could cause your symptoms for sure. Very rare on this platform, but that’s def more contamination than I’d like to see. Trace amounts are near unavoidable as motors age, but you shouldn’t be able to scoop out discolored coolant sludge like that.

[tc535i]

Originally Posted by 135Pats

If you cracked the head you’d have a serious loss of pressure integrity and compression. The car would be near undriveable, though boosted motors can create some compression under load so maybe if it was a microscopic type crack, you wouldn’t notice it

ummm... plenty of hairline head cracks act exactly like gasket leaks, we're not talking about a hole in the cylinder wall or anything here

[135Pats]

Originally Posted by tc535i

ummm... plenty of hairline head cracks act exactly like gasket leaks, we're not talking about a hole in the cylinder wall or anything here

I don’t see the disagreement here. It could be a very, very small crack. Any substantial damage to the structural integrity of the head would evaporate compression.

Bottom line, I’d be very surprised if this is anything more substantial than a head gasket. But we’re both just speculating at the end of the day, it’s not our car.

[Tommeh]

Filled with about 2qts of distilled water. There is a present oily film on the top layer of water but not like in this picture... I can no longer pull oil out. Going to flush this weekend.

[kfrazie1]

Rent a Combustion Gas tester from autozone. Fits into the coolant overflow tank and will test for exhaust gasses. If it tests positive it's most likely a Head Gasket.

[pwr hungry]

Originally Posted by kfrazie1

Rent a Combustion Gas tester from autozone. Fits into the coolant overflow tank and will test for exhaust gasses. If it tests positive it's most likely a Head Gasket.

That's really good advice. We used to use one of those when I worked at a Honda dealership years ago.

[j1gilles]

Originally Posted by Tommeh

2008 BMW 135i N54 engine with 95,000 miles. Issues with misfires on multiple cylinders (Number 3 and 4). New step colder plug gaped to .022" put in at 89k miles. Original coils, except #6 I replaced at 84k.... Never had intake valves cleaned...



Pulled spark plug #2,3, and 4 and switch cylinders #2 and #4 plug along with the coils. Haven't started to see if misfire switches from cylinder #4 to #2 because i checked my coolant, fingered the reservoir, and looks like my ol' girl has influenza....



Last year I had the thermostat and water pump replaced by an indie shop, and while getting new free OEM turbos BMW Orlando replaced the oil filer housing gasket and told me they did not need to replace any oil or coolant. So i don't know if BMW or the indie shop might have messed something up, but I need to get it fixed. Don't know the best course of action for fixing my coolant/oil mixture.

100 % normal... Change your coolant and carry on.

[joeyt]

100% normal? Are you smoking something. That is some serious emulsification there matey. Theres nothing 100% notlrmal about it. Its those type of comments that will end up with his car potentially knackered.

OP: approach this with caution as I had a 335i vert 4 years ago that killed the head gasket after a wrecked water pump replacement. I sold it to a bmw garage with the damage stated at a loss of 3k over what it was worth. It started the same as yours. 2k down the line I then had water in my oil and was pulling custard from both coolant chamber and oil filler. Shortly after came a bottom end knock and bearing damage.

Im not scaring you just letting you know that this should be carefully monitored and not to listen to answeres from people with no first hand experience.

[AK 335i]

I have a coolant system. Pressure test kit.
It will tell you if you have a blown head gasket.

Harbor freight sells kit for 80 bucks I think.

[Bakeme521]

Originally Posted by j1gilles

100 % normal... Change your coolant and carry on.

Haha the ignorance on this forum boggles my mind sometimes.

I highly doubt the car has a blown head gasket or even worse a cracked head. If it were a blown head gasket the car would lose coolant pretty quickly and it would do more than just misfire. I have cracked heads and blown head gaskets before, granted not on an n54, but there are quite a few more problems that arise than just a misfire or rarely oil in the coolant. Most of the time with a blown head gasket the car drinks coolant rather than oil being pushed into the coolant.

My money is when replacing the oil filter housing gasket they got some oil in your coolant and they didn't replace it like they told you, then you drove the car normally and it frothed up in the coolant. Or are there any gaskets or seals that separate oil and coolant anywhere else on this motor besides the head gasket? If so that could be your problem.

I would drain the oil and look at it, b/c with a head gasket issue normally coolant makes its way into the oil, not vice versa.

Has the car ever overheated before?

[Tommeh]

Did an oil change last week and it look completely normal (checked the oil again today). Not overheating stays at 210 degrees f under normal operation.


I checked the coolant when I got home today after the distilled water cycled through the system and there is no longer a solid yellowish oil residue. There is a oily film on top of the water but not a concerning amount.

Also misfire is no longer present from a days driving. I think my issue was that the spark plugs where hand loose when I pulled the coil. Tightened to 16 FT pounds and seems fine.

[Big_CG]

Everyone, lets not forget that in cold weather frequent trips where the oil doesnt get fully up to temp, the condensation that builds up does not have a chance to get burned off and shows up at the highest point- oil cap.

I wouldnt go replacing a head gasket on visual of the creamy sludge in the oil cap. Every car Ive owned has had this because I drive 5 miles commute and live in a frigid climate.

[Big_CG]

ALso, follow the misfire diagnosis thread to better identify your issues. Guessing coils, carbon build up, injectors