Mini One D - Engine Overheating

[gavers79]

Hello there,

I'm new so sorry if this is in the wrong section.

I own a Mini One D, new from 2003. Since last February - I've had a bit of a problem with it. The tempreature gauge rises and it overheats! It's a this point I realise it's drunk more liquid than Amy Whinehouse on a 12 hour bender.

Over the last year, it's been in many times, repairing hoses, checking for this, checking for that. However I've realised, the only way to prevent this from happening is to stick at 50-60mph on the motorways!

I've taken it to three garages recently - one said head gasket, one said could be thermostat or radiator another didn't know.

I'm seriously considering changing it for a new one but I just wanted to check to see if you guys had heard anything about this.

It's started doing it again (but to be honest I may have slipped up to 70 mph!) what is strange though is my interior heating has been all over the place. It's either red hot no matter what tempreature you have, or before the engine overheats it goes cold.

Would be very intersted in any info you may have

Many Thanks

Gavin

[IanT]

I am not an expert, however I recently changed the heater control valve on my sister in laws Ford KA. The car ran fine but she never got any heat in the the cabin. In the KA the Heater Control Valve is a well known point of failure. The point here is that there is a connection between the car cooling system and the heater matrix, via at least one valve. It may be there are some issues with the valve - for a KA this is about £30 and about an hours work (plus some skinned knuckles). It does however sound like there is something more fundamental wrong with the cooling system / radiator leak.

......Just looked at Haynes manual for the petrol cars - there is a sensor in the cooling system which presumably controls the fan, etc so that may be worth looking at. Does the "I'm getting too hot" light come on before it actually overheats? One final thought - have you looked on other forums for that engine - It is a Toyota engine which is also fitted in the Yaris, you may get some sensible advice from a Toyota dealer.

[gavers79]

Thanks so much Ian.

The light comes on as it is overheating - when I life the hood, the water is boiling loads and lots of steam! It does warn me though before the engine completely overheats!

Good point about the engine - do you know any good Toyota forums?

gav

[IanT]

I just typed in "Toyota Yaris D overheating" in Google and got a couple of fairly comprehensive posts - there are also some posts on this forum, I don't think you are alone and it looks like others have cylinder head problems.

[gavers79]

Thanks Ian, I'll do the same - Gavin

[elitetech]

Extract from a reply I posted in another thread:

Quote: Originally Posted by elitetech (original)

First and foremost you need to be 100% sure of the root cause.
I've been studying the mini one diesel cooling system.

Here's some data:
1. engine should run a 50/50 mix of coolant.
2. System should run at 1.1 bar
3. Thermostat opens at 82 deg celcius

if all this is done correctly, the coolant mix should boil at 107.9 degrees celcius.

The mini radiator fan kicks in at 105 deg celcius.
Therefore, if your coolant mix is too low (or level is low), if you expansion cap is not holding 1.1 bar, and your thermostat is tired - your system will boil before the fan cuts in.
Here's the critical thing though! The gauge only moves above the half way line when temperature has been at 108 deg celcius for more than 30 seconds.
This means your system can boil away at 100 to 104 degrees, the fan not cut in, the gauge read normal!


When this happens, fluid escapes through the cap and therefore the level drops. Over a period of time the level will become critically low and then finally overheat on the gauge!

I've been testing a 2003 car with 90k miles on the clock. It overheated once on the gauge! I then monitored the coolant level and noticed it must be overheating on every journey, reducing the level by a few inches each time.
I then bought new expansion tank cap, thermostat and BMW coolant from the dealer for £48.
I found the cap design has been changed, the old thermostat didn't open properly and the coolant mix was near 100% water.

Swapped it all over for the new stuff and it's good as gold now!

I'm working on a chip to reduce fan cut temperature to less than 100 degrees so this never happens again.

[gavers79]

Thanks so much for this - I'm sorry to say though I've sold my Mini now! Would have been good to know that!