I just joined up today and tried to search for my current most top of the list issue, but cannot find any threads specifically discussing it.

The issue: Although engine is warm and all seems operational, I barely get warm air to flow into cabin. The blower works fine and all the vents lower/upper can be selected and operate correctly. I just can't seem to get any heat into the vehicle.

The question: What are your experiences with this issue? What is the most likely culprit and most importantly, HOW DO YOU CHECK IT? My immediate thoughts go to the thermostat which I did find plenty of posts on, but most related to a leaking stat or an overheating engine. Neither of these are my issue.

I just purchased my 2003 MCS used which has 130K mi on it. Previous owner states it "struggles" on cold days. Frankly, the heater either works or it doesn't! It's been in the teens here in NC the last few weeks and I'd like to get this fixed ASAP!!

Thanks for all help and advice!
-Pat

 

First thing to check, open the hood & make sure you have enough coolant. Without coolant there is no heat.

 

2003....
Any idea if the coolant has ever been changed....it is due every 36-48 months on a mini...and failure to do so can plug the heater core...
Might be a good time to flush the coolant... Change the thermostat... And see if it fixes the issue...
Then if it doesn't... A new heater core.
In my experience, with temps to single and even low negative #'s, a mini should put of plentiful heat, run good, and even EXCELL in cold temps...cold air makes more power...so more zip!!

 

+1 on a plugged heater core. I had the same issue with my '03. Had my shop change the thermostat but no joy. Then the core was removed; it was completely plugged- and I had been good about regular flushes at the dealer. The new thermostat and core together still cost less at the independent shop than just a core replacement at the dealer!

 

It's definitely not the coolant level which is at the proper max levels when hot. Usually automotive heat systems are fairly simple, so yes I agree it is either the stat or the core. Was kinda hoping for an easy 3rd option LOL! I guess I'll need to call the local shop and get an estimate since they'll be more experienced and better equipped than me to perform that repair. I may do the stat myself first to see if that fixes things, but from everything I've read, it seems most complaints are about a leaky stat gasket rather than a bad stat itself. Oh well, I knew it wouldn't be perfect! Let's hope there are no other major issues

-Pat

 

Make sure all the air is bleeded out of the coolant system. Its probably a plugged core but this is a longshot and cheap solution. Good luck!

 

How would one go about this procedure and could that really be the issue?

 

https://www.northamericanmotoring.co...g-coolant.html

http://www.pelicanparts.com/techarti...ant_Change.htm

 

Buzzsaw, thanks for the links! I really like the idea of the shop vac flush. The problem I will likely face is that if the heater core is indeed clogged, I'm not sure this will help. I'd have to find a way to unclog the small passages within the core and I'm not convinced this will be sufficient. However, it is a much cheaper alternative, so trying it to see what happens may be worth an afternoon

 

No, buzzsaw posted those links so you could see how to bleed the system. It shows how to do it in the later steps.

 

If you can find the procedure in earlier steps on any other link please let me know so i can update our site with the latest and greatest.

 

Double post--fat fingers

 

So, I messed around a bit more with the cooling system today. I bled the system through the upper bleed screw on the hose coming from top of radiator. It didn't need much bleeding. It hissed for a second and fluid came out right away. Then I topped off the expansion tank with a little distilled water. I did this just for good measure.

Next, I messed around with the various venting option (defrost/dash vents/foot vents). What I found was that some warmish heat is actually coming out. The most heat comes from the top vents and seemingly a bit more on the driver side than the passenger, but maybe that was just me imagining that. The most notable difference was when the heat was switched to the floor. In that position there's barely any heat produced. The airflow coming out is strong, but it's a cool air with just a trace of heat. When coming from the upper vents it isn't hot by any means, but definitely warm. In fact, when running on defrost, the defrost vents produce warm air (not hot) while the foot vent is cool.

What's going on here?

 

Sounds like either a plugged heater core or stuck thermostat.....exact symptoms for both...

 

So, I took the car over to a small local shop. They ran diagnostics and it appears the issue resides with a blend flap of some kind. I don't have a Bentley manual as of yet, so I can't study what the system looks like or how it operates. They did order the part, but it will take a little while to get since there were none in the US. Had to come from Germany.

Anyway, I took the glove box out so I could see what is going on back there. There is a lever which doesn't appear to move no matter what switches I press. This is the item I'm showing with arrows in the pics attached. Can anyone confirm what this lever does and how it functions? This may very well be the cause of my issue. Incidentally, I removed the cabin air filter and wow does this thing get dirty! I have one of those on the way as well.

 

Thought I would share and experience I had that might be food for thought if your flapper japper thing is working- and may only work with the car on as some devices may use vacuum to operate.

I recently pulled my engine and transmission to re-seal the engine and replace the clutch. When I removed my oil cooler it was packed with some sort of mud. Completely blocked. It was so bad I had to heat it with a torch and use PB blaster to get through some of it. I then used a power washer in each port to flush it. I don't think I got it clean but I didn't buy a new one and it looks to be somewhat working.

When I pulled the engine I stuck the pressure washer in the heater core hose and brown crap came out. It took about a half hour of going from the inlet side to the outlet to get clear water out!

Before the engine pull I had some heat issues in 35 degree weather. If I ran the blower on slow it would be hotter. If I cranked it up it just came out barely warm.

Now... holy smokes... on 72 it blows me out of the car. 68 is about all I can take.

Not sure where the muddy brown stuff came from... Maybe the PO used some sort of gasket sealer in the coolant system.

 

I disassembled the upper control that holds the lever shown in the pics and was able to move it up and down. It does indeed control a flap inside the bottom center of the dash area. When I pulled it up it seemed to move a vent to allow warm air to come out the bottom foot wells. This part is definitely electrically controlled as there is a plug and harness going to it.

I may actually have 2 separate issues going on at once since not only does the actuator seem to be faulty, but the heat that comes out is just warm and not hot even though the engine/coolant is at proper operating temp. So, perhaps the heater core is partially clogged as well.

Once the new actuator is installed and the system operates with no faults, then I can move on to diagnosing the temp issue. More to come...

 

One bit of info...
the logic of the automatic heater is that it will not blow hard/full till the computer tells it the car is warmed up...
if you have a stuck thermostat...it will not warm up...so the doors will not open...
Anybody plug into the odb2 port and pull the coolant temp?

 

Yes, actually the shop had quite a fancy diagnostic display and were able to control everything from there. They also verified the temp in various locations using a laser instant read thermo.

I will definitely keep this thread updated with the latest as I find out what is actually going on and what the solutions were.

 

+1 Check heater core first to make sure its not plugged or clogged:



#1 Heater Core part # 64111497527

http://www.ecstuning.com/Search/SiteSearch/64111497527/



&

#2 part # 64116924079

http://www.ecstuning.com/Search/SiteSearch/64116924079/



&

#3 The heater core mounting kit part # 64116910914

http://www.ecstuning.com/Search/SiteSearch/64116910914/



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Here are some of the main parts in the Adjustment set. You can see in the far right that it contains they little boomerang shaped part as well as the plastics rod. As well as the flaps and adjustments. So you can compare and see if anything looks broken or has snapped.

Set Of Small Parts Adjustment Lever Part #64116910916

http://www.ecstuning.com/Search/SiteSearch/64116910916/



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Just to make sure on the "auto air controls" you have it turn to high, click the center wheel a couple times all the way to "high" display.



OR

The temp dial on the left for the "basic heating / ac systems" all the way in the red ?



Thanks and let us know what you find.

 

If it is your heater control system, you're actually lucky. The clogged core is a much bigger problem with some early-production cars. Here's the tell-tale symptom: you get the car up to running temperature, turn on the heat, and you get about one minute of warmish air, and then it starts to cool down. If that's the case, your core is clogged. **Warning** before you pull the trigger with the eager-beaver parts sellers here, you have to know that just replacing the heater core and associated bits will probably not fix your problem in the long term. The problem is corrosion in the journals of the crank case, and they will just re-clog your new core. You will have to flush the F@^k out of your crank case, and then treat it with a rust inhibitor. Then you have to clean and flush your radiator--maybe even replace it. Then refill with MINI or BMW brand coolant and cross your fingers.

 

^^^ Helix- Thanks for the info & in doing so reminding us on how important things like changing out the coolant are. Preventative maintenance is always cheaper.

 

I love it when a vendor not only sells parts, but also TEACHES us about our cars and the issues we have!!
Great info!!!

 

The blend flap lever you show in post #15 just fell off on my O3 - I suspect my girlfriend kicked it off but... anyhow I had no heat for a while, once I found that and popped it back on all is normal again. I have the manual controlled blend flap however, you seem to have the full electric? Still you should be able to put it in the HOT mode manually and get some warm air???

 

Thanks all! Good info indeed! The trouble I'm experiencing is such that I only seem to have part of these symptoms, but not all.

I have the auto air and I've tested system with it on high while vehicle was at temp. My temp gauge on speedo sits right in the middle where I understand is the norm. I get warm air for sure and it never completely cools down, but it never truly gets hot either. I just recently purchased this vehicle knowing there might be a few things to correct. I didn't know that the coolant/core was such a problem though.

I've owned many vehicles in the last 30+ years and I can say that none were flushed on a regular basis. In fact, there were likely some that went over 100K mi without a flush and ran perfectly. I'm more picky these days and do perform these types of maintenance, but having acquired it used, I can't know for sure if it has been done as regularly as everyone here suggests.

I'll update as I find out more!