Oil in coolant tank, oil cap clean

Logicoeur · 06-21-2021, 02:40 PM

Currently diagnosing oil in my coolant tank

. "Low coolant" has come on 3x the last two days. No visible coolant or sludge on the oil cap. Did the OFHG and flush a few years ago, and no visible leakage anywhere at the front of the engine or near the cooler.

Recent maintainence was just the oil pan gasket (couple months ago) at an indy. Could this residue in the tank be an artifact from that work?

I can't find the specific procedure for working on the oil pan gasket, so I've attempted to work backwards from "oil sump removal" and "replacing connecting rod bearings" in maintence docs. Doesn't look like "draining coolant" is required to remove the oil pan. Also can't find any diagrams for the coolant passages in the block.

Am I looking at the OFHG again, or something worse

?

F32Fleet · 06-21-2021, 05:19 PM

Worst case is blown head gasket. There's a kit which attaches to the cooling system. It contains a dye that reacts with hydrocarbons.

thejeremyman9 · 06-21-2021, 06:05 PM

How sure are you its actually oil in the coolant tank?

Logicoeur · 06-22-2021, 06:46 AM

Quote:

Originally Posted by thejeremyman9

How sure are you its actually oil in the coolant tank?

Pretty sure. The tank is pretty new as you can see. Radiator fan went out almost two years ago and a lower hose burst. Coolant was flushed that time and tank purchased new, liquid was blue. Prior to that OFHG around 55k. Car is at 85K now on an oe OFHG.

I'll dip a napkin in and see if I can a extract some of the liquid.

Logicoeur · 06-28-2021, 09:25 AM

Definitely oil.

auburnf30x · 06-28-2021, 09:40 AM

Yup, in the first post the second picture (of the cap) shows that milky residue that is unmistakable for coolant/oil mixture. Presence of that on the cap indicates a fairly significant contamination, unfortunately.

F32Fleet · 06-29-2021, 03:06 PM

Quote:

Originally Posted by Logicoeur

Definitely oil.

Yep. Hopefully the OFHG is pinched and letting oil into the coolant.

Let us know

435GranC · 07-01-2021, 08:07 PM

Oil cooler or trans cooler issue maybe

silvermullet · 08-09-2021, 11:26 PM

hey all,

diagnosing the same problem here. 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, 04:04 PM

I think it's the OFHG, i just replaced mine yesterday and when i bleed the cooling system there was oil in my reservoir. Now i have to take it apart again and also flush my cooling system. I think the gasket didn't seat correctly.

Logicoeur · 08-24-2021, 05:09 PM

Just to update this I got the OFHG done again with a flush. Still expect some oil to appear after the flush as there are just too many places for it to hide.

Now the kicker, I was going through my docs for all the work that has been to the car over the years. Found the papers from the first time I had to do the OFHG. The shop notes they flushed the system bit it will definitely need another flush soon. I believe now that all the oil I found recently was just the remainder from the original work. It wa never flushed again in between as I never recalled to check again

. So it seems like I payed for the OFHG to be done again when all I need was another good flush smh. Lesson learned.

thejeremyman9 · 08-24-2021, 06:26 PM

So is oil in the coolant unavoidable with OFHG and therefore coolant flush required? I don't recall seeing that ever really mentioned in DIYs or anything.

Logicoeur · 08-24-2021, 07:42 PM

Quote:

Originally Posted by thejeremyman9

So is oil in the coolant unavoidable with OFHG and therefore coolant flush required? I don't recall seeing that ever really mentioned in DIYs or anything.

It seems to be entirely dependant on how the gasket fails since oil and coolant passages are separated by the same gasket.

silvermullet · 09-16-2021, 08:34 PM

Quote:

Originally Posted by Logicoeur

It seems to be entirely dependant on how the gasket fails since oil and coolant passages are separated by the same gasket.

how is your car now?

im still having oil get into the coolant tank. had the OFHG work done again, but still oil and shop said pressure building in the coolant tank.

i think im screwed. will probably trade the car in.

we just picked up the car a month ago... there was no oil in the coolant then and car drives fine. think we got f*cked over.

123Britt · 09-17-2021, 07:58 AM

I would really make sure both Gaskets are BMW OEM.
.
Made in Japan.

Logicoeur · 09-17-2021, 08:06 AM

Quote:

Originally Posted by silvermullet

Quote:

Originally Posted by Logicoeur

It seems to be entirely dependant on how the gasket fails since oil and coolant passages are separated by the same gasket.

how is your car now?

im still having oil get into the coolant tank. had the OFHG work done again, but still oil and shop said pressure building in the coolant tank.

i think im screwed. will probably trade the car in.

we just picked up the car a month ago... there was no oil in the coolant then and car drives fine. think we got f*cked over.

It's fine now. Could prob use another coolant flush to get an remnants out. The second ofhg work was unnecessary. It just needed a flush

MTWO · 09-18-2021, 10:19 AM

Quote:

Originally Posted by Logicoeur

It's fine now. Could prob use another coolant flush to get an remnants out. The second ofhg work was unnecessary. It just needed a flush

Nice

06-21-2021, 02:40 PM	#1
Logicoeur Lieutenant Colonel 990 Rep 1,934 Posts Drives: F30 335i xDrive Join Date: Feb 2018 Location: Boston iTrader: (0)	Currently diagnosing oil in my coolant tank . "Low coolant" has come on 3x the last two days. No visible coolant or sludge on the oil cap. Did the OFHG and flush a few years ago, and no visible leakage anywhere at the front of the engine or near the cooler. Recent maintainence was just the oil pan gasket (couple months ago) at an indy. Could this residue in the tank be an artifact from that work? I can't find the specific procedure for working on the oil pan gasket, so I've attempted to work backwards from "oil sump removal" and "replacing connecting rod bearings" in maintence docs. Doesn't look like "draining coolant" is required to remove the oil pan. Also can't find any diagrams for the coolant passages in the block. Am I looking at the OFHG again, or something worse ? Attached Images __________________ 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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06-21-2021, 05:19 PM	#2
F32Fleet Lieutenant General 3566 Rep 10,346 Posts Drives: 2015 435i Join Date: May 2005 Location: Southeastern US iTrader: (0)	Worst case is blown head gasket. There's a kit which attaches to the cooling system. It contains a dye that reacts with hydrocarbons. __________________ "Drive more, worry less. " 435i, MPPK, MPE, M-Sport Line
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06-21-2021, 06:05 PM	#3
thejeremyman9 Major General 4358 Rep 7,591 Posts Drives: 2015 BMW 335i Join Date: May 2019 Location: Cali iTrader: (0)	How sure are you its actually oil in the coolant tank?
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06-28-2021, 09:25 AM	#5
Logicoeur Lieutenant Colonel 990 Rep 1,934 Posts Drives: F30 335i xDrive Join Date: Feb 2018 Location: Boston iTrader: (0)	Definitely oil. Attached Images __________________ 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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06-28-2021, 09:40 AM	#6
auburnf30x Lieutenant 435 Rep 562 Posts Drives: 2017 BMW 330i xDrive Join Date: Jan 2021 Location: Auburn, AL iTrader: (0) Garage List 2017 BMW 330i xDrive [8.50]	Yup, in the first post the second picture (of the cap) shows that milky residue that is unmistakable for coolant/oil mixture. Presence of that on the cap indicates a fairly significant contamination, unfortunately. __________________ 2017 330i xDrive Imperial Blue Exterior / Venetian Beige Leather with Oyster Accent Interior / Anthracite Wood Trim
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07-01-2021, 08:07 PM	#8
435GranC Private 14 Rep 66 Posts Drives: 2016 435i GranCoupe Join Date: Jun 2019 Location: MA iTrader: (0)	Oil cooler or trans cooler issue maybe
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08-09-2021, 11:26 PM	#9
silvermullet New Member 3 Rep 5 Posts Drives: BMW 335i X-Drive Join Date: Aug 2021 Location: Seattle, WA iTrader: (0)	Oil cooler thermostat gasket hey all, diagnosing the same problem here. 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, 04:04 PM	#10
minh94086 New Member 0 Rep 9 Posts Drives: 328i Sportline Join Date: Sep 2015 Location: Sunnyvale, CA iTrader: (0)	I think it's the OFHG, i just replaced mine yesterday and when i bleed the cooling system there was oil in my reservoir. Now i have to take it apart again and also flush my cooling system. I think the gasket didn't seat correctly.
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08-24-2021, 05:09 PM	#11
Logicoeur Lieutenant Colonel 990 Rep 1,934 Posts Drives: F30 335i xDrive Join Date: Feb 2018 Location: Boston iTrader: (0)	Just to update this I got the OFHG done again with a flush. Still expect some oil to appear after the flush as there are just too many places for it to hide. Now the kicker, I was going through my docs for all the work that has been to the car over the years. Found the papers from the first time I had to do the OFHG. The shop notes they flushed the system bit it will definitely need another flush soon. I believe now that all the oil I found recently was just the remainder from the original work. It wa never flushed again in between as I never recalled to check again . So it seems like I payed for the OFHG to be done again when all I need was another good flush smh. Lesson learned. __________________ 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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08-24-2021, 06:26 PM	#12
thejeremyman9 Major General 4358 Rep 7,591 Posts Drives: 2015 BMW 335i Join Date: May 2019 Location: Cali iTrader: (0)	So is oil in the coolant unavoidable with OFHG and therefore coolant flush required? I don't recall seeing that ever really mentioned in DIYs or anything.
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09-17-2021, 07:58 AM	#15
123Britt Captain 287 Rep 864 Posts Drives: 15 M235i AT Join Date: May 2008 Location: Madison, Alabama iTrader: (0)	Ofhg - oem only I would really make sure both Gaskets are BMW OEM. . Made in Japan.
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