Confused and could do with some assistance.
 

I have a 95 E36 M3 3.0. Just recently put it back on the road after 5 years in a garage. during the process of MOT it started to over heat. by the time i got home it was almost on the red.

i have taken out the T/stat and tested it and it appears to be working correctly. the the fan and clutch appear to be working properly and i am at a lose as to what it can be. Any suggestions would be greatly appreciated.

If it starts overheating in the first drive after bleeding the system, and this is the original water pump (unlikely on a '95), then I suspect that the plastic vanes have crumbled off the water pump impeller.

If it starts overheating after a few driving cycles, then I suspect that the overflow tank has crumbled inside so it is sucking air into the system each time it cools. This cooling system really does not like air bubbles. Tiny leaks in other places can also suck air in without creating a massive water leak.

Thanks i have given up with my own efforts and put it into the garage for repair. see what they come up with. All hoses have been replaced and i was thinking along the same lines.

I would try bleeding it yourselve before giving it to a mechanic. Pelican Parts has an excellent article on it and other cooling system issues.

Thanks I have been told it would take 4 days before they could look at it so I am going to replace the water pump as a matter of course while I am bleeding the system! Does anyone have a good pic of the engine drain plug? I undid the plug I thought it was but nothing came out at all! Unless I got the right one and there is no water in the block at all!

Did you check the Bentley Manual or the TIS?