My 2003 R53 S has no heat. It has the auto climate control. I've read quite a few threads and I'm curious the process I should follow to narrow down where the issue is.

The couple of areas I see to check are:
1. Check to see if the heat flap is operational (it is - turning the heat up moved the flap, turning it off moved the flap back)
2. Thermostat/water pump: Is the engine coming up to temperature? OBDII reports it is getting to 200 degrees and the temp guage is showing almost as high as normal. This is what I suspect.
3. Heater core leaking? Nope, but could be clogged.

The heat went pretty gradually over the course of a few weeks in conjunction with a new oil leak under the car. The coolant level doesn't seem to have dropped that I can tell from the reservoir canister.

What do you all think? Should I start replacing stuff with the thermostat and then go to the heater core and then water pump if that doesn't fix it? I've read that the heater core can be clogged really easily, and I don't ever remember changing the coolant (ooops).

 

Miles? Any leaks near the water pump area? My heater core was clogged but the coolant was rust colored when I bought the car so I should have guessed.

 

Car should be on its third or even fourth coolant change/flush....
I would do it first...
Heck changing a thermostat and checking the core for clogg would be easy to do at the same time....that way you can toss a heater core in it while drained if you need it...saving lots of work.

 

110K miles, no leaks near the waterpump but *lots* of oil leaks.

I ended up changing the thermostat, and sheepishly just took it to my local mechanic for the drain, flush and install. Last night it was really warm locally and the car had heat, which confirmed for me it was definitely the thermostat.

If things weren't so crazy at work and with other things (broken furnace at home), I'd have the car apart and do it myself. Kindof embarrassed that I paid someone to do the job, actually.

The good part about this excercise is that I've made a plan now to refurbish the car including waterpump, new radiator & hoses, new oil in the supercharger, valve cover/cam position sensor gaskets and possibly a smaller pulley come springtime. I see that requires disassembling the front end of the car, so need to wait until my 3rd car comes back on the road.

Thank you all for the help.

 

Eh, I installed the axle on my car, developed a leak and I'm tired of fooling with it. Taking to mini mechanic next week. Sometimes it's just better to pay an expert.