My 08 Mini Cooper Clubman S, I noticed the coolant expansion tank is empty. It has minimum and maximum lines but there is nothing in the tank. The car is low miles (34k). I noticed the other day after driving it for a short s distance on the highway that there was water under the driver’s side of the engine on the parking lot ground. I went back and checked the spot and the water had evaporated up and left no stain so I figure it was only water and not coolant. I’ve never seen any water or coolant leaks in my garage after driving it. I’ve been given advice to try adding tap water to the expansion tank. Should I do that or just take it in to a shop for it to be checked. If I do add water, won’t that mess up the coolant ratio?
08 Mini Clubman S, empty expansion tank?
- Thread starter lokijoker
- Start date
Pure water would mess up the ratio. You do want to make sure you have a full radiator, though. Does it have a cap? You don't know how down you are on coolant.
Water is a good emergency coolant if you're stuck out in the desert or whatever.
AC condensate drips pure water. If you rub it between your fingers it's less greasy feeling than antifreeze.
Water is a good emergency coolant if you're stuck out in the desert or whatever.
AC condensate drips pure water. If you rub it between your fingers it's less greasy feeling than antifreeze.
Probably a leaky crossover pipe. It's a plastic unit that also contains the thermostat. It has a limited lifespan. If that's still the original unit it has far exceeded its expected service life of about 7 years. I never saw it leak but the cooling system lost coolant steadily and slowly.
If it's the crossover pipe I would also replace the water pump, the water pump pulley, and the drive belt. All the parts will cost around $750. 3 to 4 hours of labor.
If it's the crossover pipe I would also replace the water pump, the water pump pulley, and the drive belt. All the parts will cost around $750. 3 to 4 hours of labor.
Last edited:
Use 50/50 coolant. If you're going to use water use only distilled water, it's less the $2 for a gallon at walmart.
Is it possible that the coolant in the expansion tank evaporated? This was my Dad’s car and it didn’t get driven for over 4 years. It’s been garaged the whole time. Looking at it again with a flashlight, the expansion tank isn’t totally empty but it’s well below the minimum mark.
I suppose it's possible that it's venting thorough the cap.
Are you sure it was full when stored ?
I have no idea. I’m guessing it was. My Dad maintained all of his cars himself and his hobby was buying, fixing up cars and selling them so he always kept his cars tip top. He quit driving it because of a health issue, then the pandemic hit. So it just sat in his garage the way it was the last time he drove it.
From what I understand, the Mini radiators are not pressurized and you fill them through the plastic expansion tank.
I guess the best thing to do is fill the tank with 50/50 coolant and water and see if it keeps going down or stays filled, and then go from there. I need to figure out which coolant Mini’s take. The manual just says to have the coolant serviced and filled only by authorized Mini service.
The cooling system is pressurized. These engines run hot and require a pressurized system to keep the coolant from boiling. Most European cars take coolant via the expansion tank. If the system were not pressurized, the tank would overflow. I can't think of any modern car that doesn't have a pressurized cooling system. The normal cooling system pressure is 1.5 bar.
50/50 meaning a 1:1 ratio of 1 part coolant concentrate to 1 part water. However, if you buy the correct coolant it comes premixed.
The coolant should be G48. Check if what's in the cooling system is blue.
Yes, it is blue.
The thermostat is a non-replaceable part of the thermostat housing, squid-looking plastic contraption that includes a thick coolant pipe segment and multiple large-diameter horse barbs. The thermostat rarely fails but the housing suffers from material fatigue and leaks are common after 6 or 7 years of heat cycling. For some Mini models there are aftermarket thermostat housing kits that are made from aluminum.
Similar threads
