Oil in coolant

silvermullet · 08-09-2021, 11:33 PM

hey all,

diagnosing oil in coolant tank. no coolant in oil. no indication that its a head gasket.

previous owner said they did oil cooler gasket while doing the OFHG, but after I opened it up, it appeared that the gasket was changed however the old gasket material wasnt cleaned up properly around the coolant chamber... and it appears that there are marks indicating where the oil was pushed into the coolant chamber due to failure in the seal.

can anyone confirm my logic here?

also, any tips on how to get the mating surface cleaner? it feels pretty smooth. just used a toothbrush, cloth and brake cleaner.

thanks in advance!

minh94086 · 08-24-2021, 03:26 PM

I just replaced mine yesterday. I only used brake cleaner to clean it. After i put everything back and went to bleed the cooling system and there's oil in my coolant reservoir. I think i may have to take it apart again. Perhaps the gasket didn't seat correctly? Now i will have to flush my cooling system too.

Chadm · 11-24-2021, 05:23 AM

I believe I have this problem too. Does the condition of this coolant look familiar?

Car is a 2016 330e on 118k miles, no history of any work re: oil cooler / gaskets. Yet to disassemble.

Edit: I have now drained and removed the expansion tank. Doesn't look at all healthy...

Logicoeur · 11-24-2021, 07:02 AM

You will get quite a bit of oil stuck in the coolant passages after a OFHG failure. Do a few flushes to get it all out first.

Chadm · 11-25-2021, 05:42 AM

I popped into the local stealership earlier today to seek advice and price up the job... Oil Filter Housing removal and refitting was quoted to be around the £650 mark, plus gaskets and fluids. They said their troubleshooting to work out the source of the mixing would start with taking a sample of the engine oil and a sample of the transmission oil and test them both, since the trans cooler is also on the same cooling circuit. They did say most likely to be a gasket or seal somewhere, rather than the actual coolers or housings, but that's what scares me with taking it to the stealer - if it turns out to be a cooler then that's a much bigger chunk of cash, for a part I could get off eBay for £100. And then if it turns out to be neither of the above, but rather the head gasket, I'd need to re-mortgage the house at their rates! Defo not what you need this close to xmas.

08-09-2021, 11:33 PM	#1
silvermullet New Member 3 Rep 5 Posts Drives: BMW 335i X-Drive Join Date: Aug 2021 Location: Seattle, WA iTrader: (0)	Oil in coolant - oil cooler thermostat gasket? hey all, diagnosing oil in coolant tank. no coolant in oil. no indication that its a head gasket. previous owner said they did oil cooler gasket while doing the OFHG, but after I opened it up, it appeared that the gasket was changed however the old gasket material wasnt cleaned up properly around the coolant chamber... and it appears that there are marks indicating where the oil was pushed into the coolant chamber due to failure in the seal. can anyone confirm my logic here? also, any tips on how to get the mating surface cleaner? it feels pretty smooth. just used a toothbrush, cloth and brake cleaner. thanks in advance!
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08-24-2021, 03:26 PM	#2
minh94086 New Member 0 Rep 9 Posts Drives: 328i Sportline Join Date: Sep 2015 Location: Sunnyvale, CA iTrader: (0)	I just replaced mine yesterday. I only used brake cleaner to clean it. After i put everything back and went to bleed the cooling system and there's oil in my coolant reservoir. I think i may have to take it apart again. Perhaps the gasket didn't seat correctly? Now i will have to flush my cooling system too.
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11-24-2021, 05:23 AM	#3
Chadm Private 13 Rep 51 Posts Drives: 2019 330e Sport Pro Join Date: Dec 2011 Location: Oldham, Lancs iTrader: (0) Garage List 2019 BMW 330e Sport ... [0.00]	I believe I have this problem too. Does the condition of this coolant look familiar? Car is a 2016 330e on 118k miles, no history of any work re: oil cooler / gaskets. Yet to disassemble. Edit: I have now drained and removed the expansion tank. Doesn't look at all healthy... Attached Images Last edited by Chadm; 11-24-2021 at 07:52 AM.. Reason: Additional Image
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11-24-2021, 07:02 AM	#4
Logicoeur Lieutenant Colonel 994 Rep 1,934 Posts Drives: F30 335i xDrive Join Date: Feb 2018 Location: Boston iTrader: (0)	You will get quite a bit of oil stuck in the coolant passages after a OFHG failure. Do a few flushes to get it all out first. __________________ F30 335iX \| Remus Axleback \| Fabspeed Catted DP \| VRSF Comp IC \| 18X9 ET35 19lb MT1 \| 255/40/18 ECS \| Ohlins RT Millway Street \| Millway Control Arm Bushings \| Turner Endlinks \| TMH 75mm 14x1.5 Studs \| BMW MPerf LSD \| XDelete \| Pipercross Filter \| MHD Stg2 93
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11-25-2021, 05:42 AM	#5
Chadm Private 13 Rep 51 Posts Drives: 2019 330e Sport Pro Join Date: Dec 2011 Location: Oldham, Lancs iTrader: (0) Garage List 2019 BMW 330e Sport ... [0.00]	I popped into the local stealership earlier today to seek advice and price up the job... Oil Filter Housing removal and refitting was quoted to be around the £650 mark, plus gaskets and fluids. They said their troubleshooting to work out the source of the mixing would start with taking a sample of the engine oil and a sample of the transmission oil and test them both, since the trans cooler is also on the same cooling circuit. They did say most likely to be a gasket or seal somewhere, rather than the actual coolers or housings, but that's what scares me with taking it to the stealer - if it turns out to be a cooler then that's a much bigger chunk of cash, for a part I could get off eBay for £100. And then if it turns out to be neither of the above, but rather the head gasket, I'd need to re-mortgage the house at their rates! Defo not what you need this close to xmas.
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