External head gasket leak?

AK135i

Corporal
Dec 13, 2016
117
32
0
30
Anchorage, Alaska
Ride
2010 135i

Not exactly having good luck here, finally figured out my coolant leak. How often does this happen to n54's? I know blowing head gaskets arent too common but an external leak at the head has me surprised. The car was compression checked and cyl 1 was 18% down and the rest were fine, but no misfires and the car still runs great (at 127k). No oil in the coolant, and I changed the oil last week and no coolant in the oil either. Just curious if it's happened to anyone else. I have an entire spare low milage motor ready to go in so I'm not really sweating this. It consumes about a gallon of coolant every 600 miles currently, and consumes zero oil over a 3000 mile oil change intervals.
 
Last edited:

JayG335

Private
Apr 6, 2018
26
4
0
Ride
2007 335i FBO VVT stage2
Never seen that one before. Sorry about your luck man. Good thing you have that's spare!
 
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martymil

Major General
Sep 6, 2017
3,331
1,906
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Down Under
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S65 1m
I've seen this happen on a couple of engines, its not common but does happen.

In the end its only a gasket.
 

Bnks334

Lieutenant
Dec 1, 2016
524
340
0
New York
My n55 seems to be blowing oil into the coolant and also out of the seams of the head... Same spot you are looking at. Not looking forward to pulling the head.
 
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AK135i

Corporal
Dec 13, 2016
117
32
0
30
Anchorage, Alaska
Ride
2010 135i
My n55 seems to be blowing oil into the coolant and also out of the seams of the head... Same spot you are looking at. Not looking forward to pulling the head.

Yeah I'm just riding on borrowed time at the moment, I have no fluids mixing yet. So I just add coolant once a week at the moment. Good luck
 

AK135i

Corporal
Dec 13, 2016
117
32
0
30
Anchorage, Alaska
Ride
2010 135i

AK135i

Corporal
Dec 13, 2016
117
32
0
30
Anchorage, Alaska
Ride
2010 135i