F80 Coolant Leak from IC Reservoir

Nanometer · 07-18-2023, 06:09 PM

Hey there!

Could use some help with my 2017 F80.

Background:
I walked into the garage today and noticed that after a week of not driving my F80, keep that one week time frame in mind, that there was a puddle of fluid on the floor. Thought it was oil, and did the taste test and it was actually coolant. I looked under the hood and noticed that the intercooler cap was leaking which is odd, so I loosened it. As I continued to loosen it the cap released a significant amount of pressure. Mind you again, this car hasn't been driven in a week.

Question:
What on earth could cause this condition? Has anyone seen this before? Why would the system be under such enormous pressure? This can't be normal since its just a coolant system. And that the car was cold for such a while. Never seen this behavior before and I am hope it is not something serious. Hoping one of you can help!

Edit: I have opened the reservoir cap every couple days and I keep discovering pressure in the system. I do not believe this is related to hot and cold weather, or could it? I am noticing a lot of pressure build up, and it seems excessive... just looking for clarification. Perhaps I need a new reservoir and or cap?

JAI///M3 · 07-18-2023, 07:44 PM

Taste test? lol

My guess is the Intercooler is leaking and boosted charge air leaked into the water circuit and pressurized it.

Nanometer · 07-18-2023, 09:19 PM

lol yes... my auto tech teacher in highschool said oil tastes different from coolant

And thanks for your input, that makes so much sense. Bad intercooler? bad gasket do you suspect? Is this a common failure?

s55jesus · 07-18-2023, 11:40 PM

Quote:

Originally Posted by Nanometer

lol yes... my auto tech teacher in highschool said oil tastes different from coolant

And thanks for your input, that makes so much sense. Bad intercooler? bad gasket do you suspect? Is this a common failure?

Undo the J pipe portion and see if there is coolant leaking into there. I had mine leak last year with only 37k miles on the car.

RElias21 · 07-20-2023, 08:46 PM

Quote:

Originally Posted by Nanometer

lol yes... my auto tech teacher in highschool said oil tastes different from coolant

And thanks for your input, that makes so much sense. Bad intercooler? bad gasket do you suspect? Is this a common failure?

https://f80.bimmerpost.com/forums/sh...570544&page=28

Nanometer · 07-23-2023, 06:44 PM

So new issue.

Every two days I have opened the coolant reservoir pictured above, and a significant amount of pressure has built up in the system. Now I do understand it gets hot and cold during day and night respectively, but I feel that this is significantly more pressure than there should be. Any ideas? I do not believe I have an intercooler leak, as if the car was sitting and since having been the reservoir cap removed several times to relieve pressure, there is no boost to charge the system.. Any ideas? This has me stumped...

paulo_f80m3 · 07-24-2023, 03:14 PM

Quote:

Originally Posted by Nanometer

So new issue.

Every two days I have opened the coolant reservoir pictured above, and a significant amount of pressure has built up in the system. Now I do understand it gets hot and cold during day and night respectively, but I feel that this is significantly more pressure than there should be. Any ideas? I do not believe I have an intercooler leak, as if the car was sitting and since having been the reservoir cap removed several times to relieve pressure, there is no boost to charge the system.. Any ideas? This has me stumped...

Check the intercooler for leaks by pulling it off the J-pipe. That is a low pressure system. I just replaced mine as a preventive of them failing and I performed a level check right after a 100+ mile trip. I took the cap off with ease and the level was perfect.

hellokitty · 07-24-2023, 03:23 PM

Just replaced the small tank, cap, intercooler and engine side coolant reservoir for good measure.

My small tank and intercooler was leaking. 2017 with 50k miles.

ringo9 · 08-08-2023, 01:44 PM

New to all this as I recently bought a F80 but seems coolant leaks are so common (that other thread is 30+ pages long) that is already giving me more worries than I would need...

After those reads I decided to go and check my coolant level and... wouldn't you guess, it's sitting a few mm below the MIN of the plastic stepped yellow gauge.

However, the reservoir I mean is not the one pictured by the OP here, I believe that one in the picture is "secondary" reservoir for intercooler loop?

So my main one at the front was low, does that automatically mean I have an issue considering I don't know when it was the last time it was topped up? Is it normal for these engines to consume some coolant or the level should stay at MAX for life? Shall I just top up and monitor over the next weeks?

Another thing, I also checked the back reservoir, the one further back was much harder to open, I used a strap for oil filters, there was a little bit of hissing when I opened it, but the level was on MAX on that one. Now I worry if I should have ever opened that and introduced air, but since it has instructions on how to check for min/max i guess it is meant to be opened?

07-18-2023, 06:09 PM	#1
Nanometer Vice Admiral 33 Rep 168 Posts Drives: 2017 M3 Comp & 2020 X5 M50i Join Date: Sep 2013 Location: West Hills, CA iTrader: (0) Garage List 2017 BMW M3 Comp [0.00] 2020 BMW X3M Comp [0.00] 2020 BMW X5 M50i [0.00]	F80 Coolant Leak from IC Reservoir Hey there! Could use some help with my 2017 F80. Background: I walked into the garage today and noticed that after a week of not driving my F80, keep that one week time frame in mind, that there was a puddle of fluid on the floor. Thought it was oil, and did the taste test and it was actually coolant. I looked under the hood and noticed that the intercooler cap was leaking which is odd, so I loosened it. As I continued to loosen it the cap released a significant amount of pressure. Mind you again, this car hasn't been driven in a week. Question: What on earth could cause this condition? Has anyone seen this before? Why would the system be under such enormous pressure? This can't be normal since its just a coolant system. And that the car was cold for such a while. Never seen this behavior before and I am hope it is not something serious. Hoping one of you can help! Edit: I have opened the reservoir cap every couple days and I keep discovering pressure in the system. I do not believe this is related to hot and cold weather, or could it? I am noticing a lot of pressure build up, and it seems excessive... just looking for clarification. Perhaps I need a new reservoir and or cap? Attached Images __________________ 2017 M3 Competition \| Carbon Brakes \| Dinan Suspension \| MHD Stage 1 2020 X5 M50i \| JB4 Last edited by Nanometer; 07-23-2023 at 11:10 PM..
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07-18-2023, 07:44 PM	#2
JAI///M3 Lieutenant 528 Rep 502 Posts Drives: F80 M3 Join Date: Dec 2021 Location: East Bay iTrader: (0) Garage List 2018 F80 [0.00]	Taste test? lol My guess is the Intercooler is leaking and boosted charge air leaked into the water circuit and pressurized it.
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07-18-2023, 09:19 PM	#3
Nanometer Vice Admiral 33 Rep 168 Posts Drives: 2017 M3 Comp & 2020 X5 M50i Join Date: Sep 2013 Location: West Hills, CA iTrader: (0) Garage List 2017 BMW M3 Comp [0.00] 2020 BMW X3M Comp [0.00] 2020 BMW X5 M50i [0.00]	lol yes... my auto tech teacher in highschool said oil tastes different from coolant And thanks for your input, that makes so much sense. Bad intercooler? bad gasket do you suspect? Is this a common failure? __________________ 2017 M3 Competition \| Carbon Brakes \| Dinan Suspension \| MHD Stage 1 2020 X5 M50i \| JB4
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07-23-2023, 06:44 PM	#6
Nanometer Vice Admiral 33 Rep 168 Posts Drives: 2017 M3 Comp & 2020 X5 M50i Join Date: Sep 2013 Location: West Hills, CA iTrader: (0) Garage List 2017 BMW M3 Comp [0.00] 2020 BMW X3M Comp [0.00] 2020 BMW X5 M50i [0.00]	So new issue. Every two days I have opened the coolant reservoir pictured above, and a significant amount of pressure has built up in the system. Now I do understand it gets hot and cold during day and night respectively, but I feel that this is significantly more pressure than there should be. Any ideas? I do not believe I have an intercooler leak, as if the car was sitting and since having been the reservoir cap removed several times to relieve pressure, there is no boost to charge the system.. Any ideas? This has me stumped... __________________ 2017 M3 Competition \| Carbon Brakes \| Dinan Suspension \| MHD Stage 1 2020 X5 M50i \| JB4
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07-24-2023, 03:23 PM	#8
hellokitty Brigadier General 2896 Rep 3,726 Posts Drives: '17 M3 ZCP DCT Join Date: Jul 2010 Location: Southern California iTrader: (2)	Just replaced the small tank, cap, intercooler and engine side coolant reservoir for good measure. My small tank and intercooler was leaking. 2017 with 50k miles. __________________ 2017 F80 M3 ZCP / AA GESI DPs / Akrapovic Evo / BBS FI-R 19" / Bend Calibration ECUTEK Flex Fuel \| Bilstein B16 DDC + CS EDC / BMC Filters / BMS OCC / CSF HE / ESS CP / Nitto NT555R2 / PD Crank Hub / SPL Suspension / Uniden R7 / Wagner Top Mount IC 2021 Mini GP3 / BMC Filters / BM3 / Cary Jordan E30 / Wagner IC / Remus Race
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08-08-2023, 01:44 PM	#9
ringo9 Private 13 Rep 80 Posts Drives: 2018 M3 Competition DCT Join Date: Jul 2020 Location: All over Europe iTrader: (0)	New to all this as I recently bought a F80 but seems coolant leaks are so common (that other thread is 30+ pages long) that is already giving me more worries than I would need... After those reads I decided to go and check my coolant level and... wouldn't you guess, it's sitting a few mm below the MIN of the plastic stepped yellow gauge. However, the reservoir I mean is not the one pictured by the OP here, I believe that one in the picture is "secondary" reservoir for intercooler loop? So my main one at the front was low, does that automatically mean I have an issue considering I don't know when it was the last time it was topped up? Is it normal for these engines to consume some coolant or the level should stay at MAX for life? Shall I just top up and monitor over the next weeks? Another thing, I also checked the back reservoir, the one further back was much harder to open, I used a strap for oil filters, there was a little bit of hissing when I opened it, but the level was on MAX on that one. Now I worry if I should have ever opened that and introduced air, but since it has instructions on how to check for min/max i guess it is meant to be opened?
	Appreciate 0 Quote