Hello everyone,

I've got an 03 Cooper s and the heat isn't working. The blowers run fine, but at most the air is just warm. I've read threads about how to check the heater core under the dash and when I did that, both the inlet and outlet were very hot. I assumed that meant that the core was not plugged and decided to take the mini to the shop and have it diagnosed. The shop just called me and said that the heater core is plugged, rusty, and needs a coolant flush because the previous owner had used some kind of thick coolant that plugs leaks. The shop said it would run about $1300 to do all this and I immediately knew I could do it for less. My question is, since the inlet and outlet of the heater core both felt hot to me, could it still be plugged? I took the plastic cover off under the steering wheel to feel the tubes literally coming right out of the heater core. Also, how hard is it to do a coolant flush and in your opinions, do you think that will fix it? Videos of how-to's would be appreciated

Thanks!

 

Replace the core....bet it has tons of sediment mix with the sealent (that is WHY IT CLOGGED)... Will happen again...
Flush the CRAP OUT OF THE ENTIRE COOLING SYSTEM....
Might be a good idea to add a good sealant/anti corrosion additive....
Close up and refill, then bleed....and look for the leak the prior owner tried to seal.......
Using the "mechanic's" in a bottle almost always ends up costing you.....
DRAIN AND FLUSHES ARE DUE EVERY 36-48 MONTHS....the most often neglected item on a mini.

 

Touch both tubes closest to the core. Make sure its just not one of them.

Link to heater core diagrams.

https://www.northamericanmotoring.co...-in-cabin.html

If the previous owner put in a stop leak in the coolant it might be partiality clogged. Flush in reverse.
I would also check to make sure you are getting full operation out of the fan and air coming into the cabin past the cabin filter. If the cabin filter is clogged or rodents make a nest on it , you will not get the flow of air.

Cabin filter:

https://www.northamericanmotoring.co...irty-side.html




Thanks and hope that helps.

 

Thanks guys! I'll definitely check the cabin filter. The AC air flow is fine, it's just that the air won't heat up when I turn the heat on. Even if that's not the problem though, the filter should probably be changed anyway. One more question, should I flush the system with the old heater core still installed or should I install the new one and then do the flush? I only ask because I don't want the leftover stop leak coolant to clog the new heater core also.