My 2007 Cooper S over heated pretty badly a while back and ended up having to replace the the water pump and thermostat housing. The car ran fine for a while until a couple months later. I took the car into the dealership and they were doing work on my turbo to get it spooling again when they called and told me I had no heat coming from my heater core and that it had failed. I hadn't noticed this problem at all until they said something. I think they wanted around $600 to replace the heater core, but I chose to wait on it not fix it. It's been very cold here recently in Colorado and I haven't been able to drive because I have no heat to defrost, so I started doing some research and it seems really easy to replace on my own, but I'm a bit confused as to what they told me. They said that the heater core failed, but all I'm seeing as far as heater core failures go is a leak in them, but I have no leak in mine and I'm not losing coolant anywhere. Is it possible for it to just get clogged up and have no flow? Is it possible that its a faulty thermostat that's not sending coolant to the core at all? Any help or explanation would be greatly appreciated.

 

Heater cores can become clogged, especially if someone has used any type of cooling system stop-leak crap. Not sure of the exact cooling system bleeding procedure, but there may be an air bubble in the system. Search the forums for "cooling system air bleeding" or similar. I am sure it's here somewhere...

 

This is why we need a temp gauge in our cars. If the thermostat failed, the temp would never reach normal and you'd know that was the problem.

 

First of all, confirm that it's the heater core that is the problem (and not a thermostat that is stuck open). Clogged heater cores are VERY rare, but not unheard of. If that is your scenario, the hot coolant is not making it to the interior of the car, but is still circulating through the engine and the radiator. You should be able to confirm that by measuring coolant temperature in the fill tank (be careful - it is under pressure when the engine is warm).

When was the last time you had flushed the cooling system in your car?
If never, you you may want to consider a flush before tearing apart the dash to replace the heater core. You need to drain the coolant regardless before you open up the cooling system to remove the core, so might as well give flushing a shot!

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Did the heater ever work after they replaced the thermostat and water pump? It sounds like you're not sure if it ever worked or not. I'd first try bleeding the system. The R56 is kind of a pain but i find it goes easier if you do it with the front end lifted up on jack stands/ramps.

 

I recently replaced the thermostat and did a coolant flush on Sunday because of the no-heat problem, and then once I replaced it, heat came right back. I've also heard that the heater cores rarely go bad or get clogged, but the thermostat is a common issue.

I've also heard that filling the coolant tank and bleeding the system will sometimes be the fix. But this wasn't the case for me. I knew it was the thermostat from the beginning.

 

Could very well be a bad thermostat or huge air pocket but you guys would be surprised how many cars come in with clogged up lines and heater cores not particularly minis but I actually made an adapter so I can out a hose on one line and put it on full blast so it flushes the crap out of it and sometimes the biggest chunks come out and the nastiest stuff lol

If you have no heat I doubt it's the heater core very rare that's your issue also one of the more expensive issues to deal with.

( sorry I said and so Much lol)