Hi everyone!

I have a 2018 F56 Cooper S at around 97,300 miles. Been a great car for the six years I’ve had it. And I’m still quite happy with my car all this time later.

Lately, I’ve been experiencing an issue where my heater appears to be blowing somewhat weakly, and not getting near as hot at as low of temperatures. For example, I use manual mode and typically use the vents at steering wheel level to keep my hands warm. Previously, when I’d have the temperature set between 72-74 or so, it’d be pretty warm. Now, I have to keep it at 78 or above, even when the temperature outside is above freezing. Which, if it’s on automatic mode I could see, but this is happening on full manual heating mode.

I’ve also noticed that it takes longer from a cold start to get the heater to blow warm, though it does to a point once my engine is warmed up (indicated by my temperature readout on the instrument cluster saying “OK” and showing right dead center between the blue and red mark).

A few things to note:

1. The car is full of coolant, with no visible leaks. The coolant was flushed in November, 2022 at about 85,000 miles or so. It’s been kept on its factory maintenance schedule since brand new

2. The engine has never once ran hot. It always warms up in the normal few minutes/miles, and has never run above normal temperatures per the readouts I’ve kept track of. I’ve been monitoring the gauge as closely as I can. No engine lights have triggered.

3. The air conditioning is working perfectly fine, no issues with temperature control with A/C.

I ran my Carly scanner and the only codes I received at all under Climate Control were:
- INFO 078003 - “Nvm e req failed”
- INFO 078042 - “Ipdum e transmit failed”
- INFO 078043 - “Linif e response”

These seem to be random ghost or random glitch codes but I can’t find much info on any of them.

A few speculations I’ve had were:
- Thermostat: However, engine has not run hot at all, no drivability issues whatsoever, and seemingly no issues with coolant, so thinking it’s not that

- Heater Core?
- Maybe a blend door?
- Perhaps I’m simply going insane and it’s fine? Lol

I have a service appointment scheduled on the 18th but wanted to get some insight in case anyone has experienced this before. I can’t find much on HVAC issues with F-chassis, it’s 90% second gens.

 

Check for a small leak at the oil filter housing, leaking coolant maybe into oil? All i can think of is that and you can see it?

https://www.northamericanmotoring.co...diag-help.html

 

Reading through this thread, that’s kinda what I’m leaning towards, based on the similar symptoms especially, appreciate the link to that. I definitely actually do have a leak somewhere as I was low upon checking again today. It’s going somewhere as it’s not pooling underneath that I can see. I was actually able to drop it a bit sooner seeing that it appears to be a bit more pressing than originally thought. Will update back once I get a diagnosis. Thank you for the response! And appreciate you all, done a decent bit of business with you

 

Just wanted to update this thread that it was indeed the oil filter housing. Thank you again!

 

Glad you identified the issue. Going forward something you should know -- even if a fluid leak is *bad*, the underbody shield is fibrous and absorbs fluids. Even after I had no heat whatsoever and pulled a code about the turbo running in some sort of protected mode due to lack of coolant, I had no pool of anything -- until I sat the car in place for several days unused, and THEN, after things got *that* bad and I let the car sit *that* long, I finally got some puddles.

Moral of the story is that if you are ever looking for leaks, drop the underbody shield, examine the underbody shield, and look at all the stuff that shield covers for evidence of dried fluids of whatever kind.

One of the blessings of doing my own oil changes, and doing them every 5K miles, and of "unnecessarily" removing the whole underbody shield to do it (vs. working through the shield's access doors) is that if dried-up-anything (or only sort-of-dried-up-anything) shows up and I'm paying attention, I'm going to notice.

Hope this is useful!

 

That is indeed quite helpful, I appreciate the comment. Definitely a learning moment for me. I had expected to see puddling of some kind, and between being full the last time I checked the coolant, engine temps never going above “OK”, and lack of visible puddling or even dripping, the lack of coolant so soon after was a surprise. But it makes a lot of sense putting the pieces together now.

Overall, I really am still quite pleased with the reliability of this car. I’ve owned a Gen1 and Gen2, plus worked at a MINI dealer for awhile as well, and the F cars have really held up quite well. In near 100k miles with this car, I’ve had very few headaches with it.

 

Awesome! Glad to help.