Has anybody out there have a good way of diagnosing a supercharger and or waterpump. I have a overheat problem that began after hearing a pretty substantial rattleing noise. Next day I have no rattle after starting but pegs the temp guage right now. I had it at the dealership and they say by feeling the supercharger pully it seems solid. They can only offer guesses with large chunks out of my wallet. Thanks for any comments

 

Bad thermostat?

 

Did they indicate they thought the rattled came from the water-pump/sc pto gears getting chewed up? Usually has worseing rattle/chain dragging sounds, followed by over heating....when the sounds stop (the gears are now gone...due to lack of lube).
Dealer will sell you a remanfactured sc for about 2x the cost of a rebuild....and a new waterpump....
If you have a comptentant mini centric shop...
you might save $$ having it towed there...driving it with an overheating issue can crack the head or blow the head gasket....
Basic trouble shooting needs to be done...just like you asking/providing more info on what the car was doing in the days leading up to the issue...very little info here other than to offer a WAG.

 

Thanks Zippy for the response. I was trying not to be to long winded.The dealer said they could not tell about the supercharger or waterpump. They did do pressure test on the cooling system and could find no leaks.They then performed a leak down test on the head and found one cylinder to be below acceptable percentage at 7%. Dealer says probable do to valve guide wear from carbon build up. They want about 3K to do that and cant say that will solve my problem. I dont think it will. My 04 MCS with 109K probable could use some freshening up but that does not explain why I had rattleing noise prior to the overheat and not the next time I started the car. Dealer cant duplicate the noise either.One other note. I was feeling power loss prior to this accurance and had gone to my local parts suppy and bought spak plugs and oil change stuff and when pulling plug realized I had wrong plug so I did not do that job but did change oil& filter the nite before. Afterward started the car to check everthing over and had no problems. Next day drove to Ciny with rattle [didnt seem to loud but I am half deaf] drove all day without overheat but it did as I got home.

 

First thing....
Check the coolant level...seems simple, but many mini's have a few slow leaks....and do you hear the cooling fan....hope the dealer did the basics...but....heck...free to check...if it did get low, you could have a bit of a airbubble....they tend to overheat when this happens, but mostly pretty quick
Rattle could be from the sc gears, but could be from a bad tensioner...would not cause overheating.....but rattle and overheat could be seperate...one thing....sure it was a mechanical rattle...a bag ping or knock can be followed by overheating.....using 90+ octane fuel right....you know you have a bit of a low compression on on cylinder...so the rattle might be knock/ping/preignition....but are kinda distinct, but figured i would mention it just incase you have neaver heard it when bad in a car...tends to worsen with throttle use/load....
One trick....with the car running, use either a piece of tubing (like a garden hose, 3 feet, or more commonly a part of a broomstick or a true "mechanics stechascope", and try to find the location of the "rattle".
If the sc pto gears a going, it should rapidly worsen, with it being ok at higher speeds, and overhearing at low speeds (engine) as the worn gears turn the wp less and less...
Any odd smells or lights other than temp when it overheats/almost overheats?
The sounds of the wp gears going are kinda distinctive...quite a few posts around between here and utube....but simple decription is kinda a chain dragging sound to more of a high pitch squeel.....

 

good thoughs I have done the hose/broomstick trick before. It can be very revealing. However I did mention the sound did go away. I think I have heard chain tensioner noise before on start ups but that tends to fade and this sounded a lot like that but a lot worse. Anyway it is coming home on the tow truck today. Maybe I will dig into tonite and see if I can get more facts. I will let you know. Thanks