01-13-2025, 01:18 PM | #1 |
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Code 1D2008, no heat, CEL on, radiator fan fully on
Hi everyone,
My 2018 M2 DCT is having a cooling system issue. I know there is an F87 forum, but my car has the N55 and this particular issue I'm having has been reported on the F series forums but no ultimate fix has been posted....from what I can tell after scouring the internet since yesterday. Ambient temps are currently 10 to 25 degrees F. The issue my M2 is having (started last night) is the following: 1) No real heat through the vents 2) Oil temp gauge indicator "tick" which indicates the temp on gauge is no longer showing. It just shows 160 to 340 with no tick mark. 3) After 10 minutes of driving, the radiator fan will run at full tilt all the time and even runs for a few seconds after turning off the car. 4) A steady CEL comes on once the radiator fan starts going bonkers. 5) CEL shows 1D2008 "Map thermostat: Stuck Open" 6) Engine runs a bit rough at idle. 7) If I turn the engine off and then try to restart, the engine runs really rough and even stalled once. This also results in a number of multiple cylinder misfires stored in the DME. 8) If I let the car cool off completely, it will restart fine (from what I can tell). 9) When monitoring the coolant temps from a cold start, the temp goes up to 130-140 degrees F and holds and then after maybe 5-10 minutes, the temp immediately shoots to 220 F and at that point, the radiator fan goes full tilt. 10) If I clear the codes while this is happening, it will turn off the fan, the tick mark reappears on the oil temp gauge, and then the coolant temp falls to 130-140 F, the tick mark on the oil gauge disappears, and then the whole thing starts over. I've owned the car since November and it's completely stock. I bought it from a BMW dealer in MI. The car is not under warranty. I see no evidence of parts repairs. Coolant level in the reservoir is fine and I've run a bleed test with no change with the issue. I've done a ton of research since last night and it's an issue (they had all the same symptoms I did) that has stumped many, including techs. People have thrown the parts cannon at the issue including new engine and transmission cooler thermostats, water pumps, various temp/coolant sensors, and even the radiator, etc. The engine thermostat would have seemed the most obvious source, but people have replaced them multiple times with no change. I would love to hear from anyone that has had this issue and what the fix was. I have an appointment at my dealer but the earliest they can get me in is 1/28 which is ridiculous. I am a DIYer and I'm not afraid to tackle things assuming someone has had this issue and they post the fix. Much thanks for your time.
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01-13-2025, 03:48 PM | #2 |
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Drives: 2016 M235i
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Do you have a scanner that can monitor water pump RPMs? It may not have fully failed but its controller may be the cause
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01-13-2025, 05:13 PM | #3 | |
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Quote:
It looks like some N55 owners fixed the issue by replacing the automatic transmission heat exchanger which has a coolant circuit and internal thermostat and the thermostat jams open. The problem is for me that my M2 has a DCT and the DCT fluid heat exchanger has no connection to the engine coolant or oil circuits like the F series automatic transmission do. Now I'm trying to figure what other engine coolant or engine oil thermostats there are on my M2. I'm scouring realOEM and the internet and I'm not coming up with anything ![]()
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