I have an 03 mini cooper s. The heater only blows ambient air. I just replaced the thermostat, housing, and flushed the system, and still no heat. It doesnt over heat, the gauge always sits on the midway mark after warm up. I have ample air blowing out of all vents so i dont think the duct work is lose or disconected. Any help would be greatly appreciated. My wife drives the car daily to work.

 

Did you bleed the air out of the cooling system with the heat on after flushing?

 

Yes i bled all the air out of the system, it took quite awhile but i finally got it.

 

It sounds like you either still have air in the system or the heater core is partially blocked. I would try purging the air using again using the bleed screw and having the heat on max. Air trapped in the system causes the exact symptom you describe. Was the reason you did the work on the cooling system the lack of heat to begin with?

 

Yes all the symptoms i listed above were present before i changed the thermostat and flushed the system. when i bled the system after flushing I used the bleeder screw on the upper hose. I did it for about an hour until all i got when i opened it was coolant.

 

Also I did have the heat on max the entire time i was bleeding the system

 

The s has 2 bleed screws....
Have you tried going under the car and unplugging the hose that goes into the firewall that goes to/from the core to see if it is full?

 

I have not tried that yet. I will have to check that out later today or tomorrow

 

Where is the second bleeder screw? I only saw the one on top of the upper radiator hose.

 

The second bleed screw is on the heater core return hose between the engine block and the firewall. I can access that one from the top of the engine using a long screwdriver, but I don't have an 'S'.

I'm having a similar heat issue, but I haven't tried to fix it yet. With winter fast approaching I'll do that soon and let you know what worked for me.

 

As luck would have it:

I just changed the coolant and have opened the bleeder valve by the radiator 3 times (not much air, some air, and more air). I DO have plenty of heat.

Now I read that there is a second bleeder.

I can’t find it and maybe the OP can’t either???

ab

 

The second bleeder screw (which looks identical to the one by the radiator) is located about halfway down the block on the right-hand side if you are looking at the engine. You will see two hoses that run from the engine block to the firewall (for the heater core). The bleed screw is on the upper hose. I found it easist to spot by leaning over the passenger "fender" with a flashlight pointed towards the driver's side.

 

I appreciate everyones help and input on this. I will try to bleed more air from this second bleed screw as soon as i have time, then post what i find. thanks again for the help

 

On the S , IF i remember right, the second bleeder is by the thermostat...
If you go under the car, and unplug the heater core...you can let coolant flow through it from the resiviour if you have a helper keep it full...
A poor man's core flush....
I think you said you installed a new thermostat...any chance it is in backwards?!

 

No the thermostat is in correctly, I had the problem before i changed it, I was hoping to fix it by changing the thermostat.

 

Ok so I finally got around to checking it. bled from both bleeder screws no air and still no heat.

 

Being that you had the problem before beginning work on the cooling system and replacing the thermostat, the other likely culprit is a blocked heater core.

 

Hi you can probably save yourself some time here.. It's a common problem with mini ones if you look inside the car bellow the heater controls to the side you'll see a cable and a plastic triangular unit check this as it commonly comes loose.. It's the heater control cable ie hot to cold selector

 

i seriously doubt the heater core is blocked. similarly its more likely that the air duct coming from the heater core is blocked by a frozen blend door. could be somthing wrong with the module not commanding the door to open(most likely), the blend door motor is burned out(not likely), a problem with one of the bowden cables(not likely), or the door is just mechanically stuck closed(not likely). i say most likely the module because it sounds like your not getting any heat from any of the vents which could very easily be something as simple as the temp sensor input to the module assuming that you have auto climate control. i wouldnt be too worried about there being air in the heater core. it will still heat soak if there is even a little bit of coolant flowing through it and the air will eventually bleed out and move to the reservoir, but if your really concerned about it i know sometimes you can hear it when you start the car or burp the throttle. it sounds like water swooshing around somewhere behind the dash. iv never worked on a mini HVAC system before so i am no expert on them but this is just what it seems like to me

 

I have no heat and checked the following

Bled cooling system from upper radiator - no air
Bled cooling system from heater core return - no air
Coolant coming from bleed screw on core return indicates flow
Blend door changes position when set to Low temp
Heat begins on driver's side only after hard acceleration
Heat quickly fades when RPMs are reduced
Temp needle rises normally to middle and stays there
Cooling fans seem to come on at appropriate times


What am I missing? It's cold.


Someone suggested a fuse. Any details?

 

Did this ever get resolved? I have all the same symptoms.

 

I removed the heater core, then ran water backwards through it. Little globs of crap came out. Radiator leak sealant maybe? Ran water forward and backward for a while until it stopped coming out. It works much better, but not perfect. I'm not ready to spring for a new one. At least not in the summer.

 

Someone used a bar leak additive ? Some people have a heater core leak or clog.

https://www.northamericanmotoring.co...acement-2.html

 

This worked for me. Look on the right / passenger side right below the glove box close to the center console mine was plastic and it was jammed. It looks like a lever you can check by turning your heat on then cold if it does not move turn your heat on and push it gently up then your heat should come on.

 

Mine will not move, is there a control motor to work this?