6 replies to this topic

[CS500]

Hello,

I would like to think I am not a newbie as I have had my little mini since 2001 but alas I am new here - It has been a great little car but over the past few years it has started to have some problems...

History:

2001 Mini coopersport 500, 1275mpi, 35000 miles no modifications.
The car doesn't do many miles and is often not run for a month, generally when it is run it does nice long trips.

Work done on the car todate: 2x new second gear syncro (2003, 2007), new water pump (2007), new head gasket (2007), various thermostats...

Thats the history out the way...

I have done a search and couldn't seem to find the right answer, so feel free to flame me if I have missed a old post that covers the following...

Problem 1. Engine overheating! I know - it's a mini, if it's not overheating, the engine is not switched on!
In town the engine seems to stay around normal temp, but when driving at speed 50-70mph the engine gets hotter than usual. The needle hovers just above the mid-point and some times a bit more, but then returns to just above normal (it has always stayed below the mid point before). There seems to be no evidence of coolant leaking. I am concern if this continues I may cook the head gasket... again. When the car is stationary the car gets up to temp, then fan cuts in and out as normal and no problems, in this situation the temp never rises more than the mid point. The overheating only occurs when driving at constant high speed, sometimes up as far as 3/4 towards red - but not into the red. If I then stop the fan is not running, but after about 10-20 seconds in cuts in and the temp returns to normal. It is as if the radiator is not getting enough air/water past it to cool the engine down at speed. It has only been doing this for the last year or so.

I am looking at new radiator? or is there something more sinister? I am really pulling my hair out with this one!


Problem 2. For a while the engine has been lumpy and jerky at low revs, ie stop-start traffic, it is almost impossible to keep a constant low speed with out kangarooing, I currently have to dip the clutch every time I lift off the throttle at very low speeds in first or second gear.

Could it be that the rough running is due to a distorted throttle body? I know the rover bodies are plastic and suffer in the heat - as the car overheated considerably (see above) and may have helped distort the throttle body...

I have read the Burlen are producing alloy throttle bodies and I am thinking of upgrading mine. The standard size is 48mm but I am considering the 52mm, are there any other mods I would need to do to accommodate the new size or is it a straight swap? Can this mod be doen in isolation and would it be worth while, seeing as I may need to replace the throttle body anyway? Also is it a better idea to keep a CS500 completely standard and replace with the 48mm alloy body?

I really hope you clever chaps out there have some suggestions because I am starting to get a little concerned the car is about the get very expensive!!

Regards

CS500

Sorry for the long post!

[BLUE ITALIAN JOB]

hi there , welcome to the forum , you said you have had the head gasket changed because it boiled up on you - did you have the ecu fault codes read and cleared ?????? the mpi mini does have alot of parts that are only for the mpi and not just for a mini , are the spares fitted for the mpi , mine is a carb but my mate has the mpi mini that has some mods that did not run very well - still had faults logged on the ecu , what part of the country are you ?? do you have a mini garage that you trust ??? my mates was well sorted and now runs/purrrs along by downton in reading, berkshire - if not in your area try give him a call ,

[taffy1967]

Could it be due to a faulty termp sensor?

[Big Man]

Fault 1 - Could be an air lock in the heating system?

Fault 2 - Could be (mines an SPI) a disconnected pipe form the rear of the throttle body to the fuel trap, mine was disconnected and ran as you describe now sorted. Or pipe from fule trap to ECU. just check your pipes any splits whatsoever and change the connection.

Hope this helps, oh and not advice to fix just advice to check first hope it helps

BM

[elvisthepizzaman]

RE the kangarooing at slow steady speeds. Disconnect the map sensor and clean the contacts with fine sandpaper then spray the connector with electrical contact cleaner. Make sure the wiring harness is still attached to the throttle body bracket. if the harness is not then engine vibrations are transferred to the connector and it tends to cause fluctuations in the map sensor readings as the connection is constantly being broken and reconnected plus the contacts over time will get pitted from the electrical fretting that occurs due to the vibrations. Took me a year to figure out this one. If the fretting gets bad enough then it can cause stalling and misfires.

What kind of oil are you using? use at least a 10w40 or 20w50

have you checked the black plastic cap on the radiator for signs of leakage? take it off and look at the underside, make sure that the small round dot is in the center of the cross if its not then the metal pressure valve is not seating properly and you will be loosing pressure in the system leading to overheating. Also, check the plastic tank for signs of cracking.

Edited by elvisthepizzaman, 24 November 2008 - 12:51 AM.

[CS500]

Thanks for the replies, gives me a few things to check...

BIJ - I am based in London, car is currently serviced in Putney, and is currently with them as they are looking into the problems. They have serviced the car the past few times and have always been good. As for the fault codes, I assume they have checked them to see if there are any. I will ask them.

[minicooper1.3i]

I had a very similar problem with mine, caused by a break in the loom to the MAP sensor. The break was caused by engine rock when the steady bushes had worn. Sometimes it was fine but driving through traffic meant increased engine rock and a nightmarish drive. Not to mention an aching clutch knee. A change of the engine loom took about half an hour and sorted it completely.

I wouldn't have found the problem if it hadn't have been for the help of DC Mini's in Potters Bar (north london). A Mini specialist I can highly recommend.