Hello everyone! Have a 2006 Mini Copper S. Have a very small antifreeze leak from the back side of motor seems to be dripping from the back upper side of block. Could it be a headgasket or something else? Loosend back shield limited view (no oil in water)

 

Have you actually seen the leak? or just antifreeze on the engine? Check your expansion tank as it is a common place to leak which could spit it out on the engine.

 

Checked tank seemed to be ok thanks, Had jacked car up got under and could see water on upper back of block side. It's a small amount of antifreeze. After using car it leak's a few table spoons each time. A pretty good shade tree mechcanic just not familiar with Mini's. Thank for any input.

 

In addition to the expansion tanks leaking at the seams overfilling sometimes is a culprit.
The level when cold should just cover the fins in the bottom of the tank.

Overfilling the tank causes it to be expelled when running at normal operating temps
as the tank is part of the cooling system and not a recovery tank.

Hope this helps...

 

If not the expansion tank or it's cap, your thermostat housing could be cracked (common problem) or the pancake oil cooler on the backside of the block could be the culprit.

 

Had taken car out for a long drive came back jacked it up got under it spent a lot of time waiting for a leak nothing, but after couple hour's later there again water under car (couple cap full). I have a repair book we had ordered but it don't show thermostate location for a Mini S. Yes I agree water on side of engine block probably did come from tank or when filling tank. Because checked again no water on block!! Thanks for your input sure need more!

 

I'm still betting on the thermostat and/or the housing. There was an earlier thermostat gasket that was inferior and deteriorated, causing leaks. The housing is also prone to cracking.
https://www.penskeparts.com/Diagrams...1&rnd=03192010 Click on diagram 11_3388.

If you'll do a search on "changing thermostat", you'll find a number of threads on this subject, I believe in the "How To" section and also on Pelican Parts in their excellent repair guides.

 

I had a small leak in my radiator that sprayed it both down on the ground and up and on my engine. This caused me to think the problem was much bigger than it actually was. I couldn't see the leak while the engine was hot and running but when i walk away and come back i could see the small puddles. So after running my car a bit i waited and when my car was cooling down and the thermostat was most likely closing, the pressure would build up since the fluid was no longer running through the radiator. Causing it to spray out a very very tiny hole in the radiator. I just put in half a bottle of some Bar's Radiator Stop Leak and it hasn't leaked since. That was over a year ago that that happened and my coolant system has been through driving in 110+ heat and below 0 in the summer without any issues. So it definitely worked and worked for good and i drive my JCW hard.