1st Gen R50 Cooper Most liked posts in thread: What is causing this to happen?

This is a guess, I am sure others will know for sure but it looks like the plastic cover must have worn a small hole in that line(PCV hose?) and it's now leaking.

 

The color looks like dried coolant spray - from some tiny coolant leak somewhere around that spot. Could be a pinhole in a hose, a bad clamp, the bleeder screw. Look at how it rings around the base of the bleed screw - that fitting may be cracked?

I don't think it's the small breather tube - that wouldn't carry anything that would make that color when dry.

 

I'd say a coolant leak too. Interesting white color, have you put in any additives (water pump lubricant)? Check your coolant level, you don't want a warped head over this.

 

My OEM coolant dries that same color when I overfill and the reservoir vents.

 

It has an interesting spray pattern. It may have a pin hole in the radiator. Check to see if the white coating is on the back side of the radiator in line with the white coating on the engine. If it is the radiator, I believe they can't be repaired, and they aren't cheap.

 

Need to pinpoint the location of the leak first. Wash off all the residue that's there now, let it dry completely. Drive the car up the normal operating temp, then open the bonnet with car still running and see if it's leaking/spraying any coolant, and, if so, from where.

The fix will depend on where it's coming from.

 

Has there been any resolution to this? My Cooper did this a few years back, but not as severe as yours pictures. I have put a some radiator stop-leak product in and all is well.