Sounds like air in the system for the heater not to be working, run(not drive) the car with the rad cap off, heaters on full but with the fans off, check the thermostat operation if the hot engine water isn't going in the radiator.

 

Thanks... i dont think the rad has a cap though??!!

 

expansion tank cap..

 

Thanks Stead34 - I did try this when I first re-filled it and the level in the expansion tank stayed constant - I was hoping it'd drop so I could get more water in it.

 

Follow the top hose out from the heater matrix and see if it has a bleed nipple, also there may be one on the thermostat housing and one top of the radiator, if so open these untill water runs consistantly out of them then tighten them...these may be there to aid bleeding...

 

I see from your previous posts that your car is an R50 Cooper. The filler cap for the cooling system on the Cooper is not on the expansion bottle. The cap is at the gearbox end of the engine, between the rocker cover and the air filter intake hose. It has (or should have) a yellow warning sticker about not opening when hot. It is sometimes difficult to open as it has the spring for pressuring the system, press it down and rotate anti clockwise. Fill the coolant here, then top up the expansion tank to the correct level. Turn the heater control to hot and run the engine, topping up the coolant as it circulates and the air comes out. There are also two bleed valves that you may need to open to let the air out. They are black and have a cross on top (two slots). One is by the filler cap, the other is at the other end of the engine, in front down by the inlet manifold for number 1 cylinder. Open these valves and let the air out until coolant flows, then close the valves. When you're happy that the system is bled, turn off the engine and put filler cap back on. Make sure the level in the expansion bottle is correct.
Be prepared for the level to drop a bit in the following days as the cooling system on these engines is notoriously difficult to bleed. Monitor the level and keep it topped up. If it continues to drop after a few days, then you probably have a leak somewhere and will need to find that (suspect the thermostat housing or the bottom corner of the radiator).

 

Hi XRV848

Thanks for the info - I didnt see it before the car went back to have a recon gearbox fitted... but I have just looked and you are spot on. Thankfully while the garage were doing the gearbox, they sorted out the overheating too - all under warranty

But thanks for your help... I'll know in future

 

heater not working

New member here, I just wanted to say thanks for all the info above, the wife phoned me while I was /am in work and told me the heater wasn't working in her 06 Mini one on the way home from work tonight, and when she got out it was making (her words) a hell of a noise, got it out of her that it was the fan, hopefully I'll be topping up the coolant and bleeding the system tomorrow with all the advice from above, it sounds like a common fault with this car design.
The above quire was the reason I've joined this forum, I myself am on two other car forums that keep me busy most nights, so I was a bit reluctant to join another one on my wife's behalf, having said that it looks like a well run site so I probably will be posting more in the future, by the way are the any photos showing where exactly the location of the bleeding valves are ?
Guvs (Steve)

 

Here's a link to a thread that shows the location of the bleed screws and also tracks down a third bleed screw that I was unaware of and have never had to use:
http://www.mini2.com/forum/maintena...um/maintenance-mini-care/190132-help-me-find-third-coolant-bleed-screw-plz.html

 

Think I've the same issue with my 04 R50 as described above but wanted to check.

I have checked coolant levels at filler and expansion tank and both seem fine. I gently loosened at screws 1 and 2 but had coolant dripping immediately.

Ran engine for 10 mins, heating on full but fan on low and with the coolant filler cap off saw no drop in levels and loosened screws 1 and 2 again and immediately saw coolant.

Going to try accessing screw 3 later once I've got tools but based on my findings so far could it be something else?

Have so far overheated twice and both occasions were after prolonged driving before hitting queuing traffic and coming to a stop and sitting in traffic. Temp levels shot up and as I then tried to pull away had a nasty scrapping sound under the bonnet. Having then pulled over and let the engine cool it was fine again within 10-15 minutes.

Thanks for reading and TIA for any advice and suggestions

 

Quick update...

After fishing around on YouTube for useful ideas to narrow down the cause of my over heating issue I'm wondering if it's the fan.

After starting engine if I switch on the AC should the fan start up immediately? Mine doesn't.

 

Quick update...
After fishing around on YouTube for useful ideas to narrow down the cause of my over heating issue I'm wondering if it's the fan.
After starting engine if I switch on the AC should the fan start up immediately? Mine doesn't.

With AC on the fan should run at low speed continually. With bursts of high speed fan. It is really obvious the fan is running high speed, makes a lot of noise and you can really hear it - not when driving along obviously, but when idling or in traffic.

When driving/running with AC off, the high speed fan should cut in at about 108-112°C. If you are stop/start driving in town traffic, hot day, window open, you cannot miss it coming on. Incidentally, the thermostat opens at about 90°C.

The temp gauge is only really a rough guide to what is going on - accurate within maybe 20-25°C. If you want to see the actual temp try the process below and watch. It won't solve the problem but may help you with the diagnosis.

Display Actual Coolant Temp
R50 Cooper and R53 Cooper S Hatchbacks 2002-2006
R52 Cooper and Cooper S Convertibles 2005-2008

1. With the key in the ignition, but in the off position, press and hold down the odometer reset button with one hand.
2. While holding the button down, switch the key in the ignition to position 1 (first click) with the other hand. The screen will have a number and the word “TEST”.
3. Scroll through the numbers by pressing the odometer rest button, through to 19 and wait a moment. (Note: the number order is: 1, 2, 10, 19)
4. The message will say 19 "L i-off", flash to "L i-on", and back to "L i-off" again. When "log i-off" appears, press the odometer rest button again.
5. You are now in the system.
6. Scroll through to 7.0 Actual coolant temp.
7. Start the engine and actual temp is displayed and you will see the temp fluctuation as the thermostat opens and closes.

 

My R52 I have to fill the expansion bottle for every run so I see those post I open those screws and filling the coolant the 1 screw quick coolant out but for the second screw it’s take more than a liters to fill before coolant comes out so I have test this week if any changes

 

I have a 2011 Mini Cooper R 56 with just under 70,000 miles. It ran great after I changed the plugs and one coil and the sensor to coolant. However, after having the footwell module replaced (under warranty) I started having problems. The mechanic also pressure tested the system and found no leaks. My own diagnostic showed the temp at 233 so I bought a new thermostat with a harness ($260) and replaced it myself. When it still overheated I checked the underhood relay/fuse box and found the Mini mechanic had removed 2 relays and 2 fuses - one controlled the fan. Since the Mini is still overheating I ordered a water pump even though I observed no leaks. I did hear a howling type sound. I need to know whether the circuit board is messed up because of the mechanic's removal of the 2 relays- one with the snowflake, which I guess is AC & the other for the fan of the main engine. Also in replacing the thermostat the plastic housing was damaged from the heat.
Rita Neumann