[Ninefourteener]

Has anyone had this problem?

Heater blows "warm-ish".... and does get warmer if I run the RPMs high.... but at idle, blows cold. If sitting at idle for any length of time... blows very cold.

Coolant level is perfect
Engine warms up and maintains correct temperature consistently without issue or variation
No CELs or warning lights.
No changes to I-drive settings, etc. It's all been checked.
Fan/blower speed seems to be appropriate - Plenty of air moving, air is just cold at idle
Problem is consistent whether air is recirculated, or "fresh" air is chosen - Same problem.

Anyone had this issue?
Any ideas?

[Ninefourteener]

No one replied after almost 8 weeks..... and there's a reason.

My car has been at the BMW dealership.... for 22 days (Yes, twenty-two)

They have torn the dashboard out twice (10 hour job each time)

They have replaced the heater core, hoses, electrical components, motorized vents, and likely a lot more I don't know (or care to know) about.

This one stumped a TEAM of BMW technicians for over 3 weeks.

(drum roll)

***** AUXILLARY WATER PUMP ******

Yea... I didn't even know such a thing exists in these cars. As it turns out, the water that goes through the heater core?? Is actually fed via an electric pump... NOT the (traditional) water pump.

But... it makes perfect sense..... if the engine was running at high RPMs, I had some "moderate" heat... but at idle... I had nothing but cold air.

Problem solved.... car is back in my hands... running as good as ever. I decided to not trade it in, and just keep it.... but it's currently back in "stock-looking" form.... going a different styling direction with it.