1st Gen R53 Cooper S Most liked posts in thread: Help a newbie! Over heating issue on a 2004 S

If "leak from the middle" means coolant was escaping from the seam on the expansion tank, then the tank should be replaced.

The MINI coolant system is under pressure to reduce the boiling point, so pressure is normal.

If the seam is not leaking, look for signs of fluid escaping around the coolant thermostat housing, if so, replace the housing and thermostat.

Overheating can be caused by a variety of conditions, insufficient coolant, water pump drive failure, air pockets, head gasket breach, etc. Leaks are first on the list of troubleshooting targets.

 

Some questions: where did you but your MINI from, did they do any work on it, do they know anything about MINIs ?
If they flushed the rad. fluid did they "bleed" the system properly and change the thermostat ? If this was not done correctly you will have air pockets in the system causing over-heating.

Good luck:confused5:

Mark

 

There was actually a recall on the early coolant tanks as they tended to split at the seam.

Get it replaced if needed and then do a full flush and replace with MINI/BMW coolant.

 

And only get it done by someone who knows how to specifically on MINIs. Having the system flushed and recharged is never a bad thing.

Mark

 

Replace the tank and flush the system.

The thermostat is not that easy to change, but models of that era had problems with the thermostat housing cracking, so you would want to look for leaks. Also the gasket has been redesigned as it to had a few issue but you can't buy it alone, it only comes with a thermostat.

None of it is that hard to do for a good tech. You don't mention where you are located so it's hard to point you to a good shop.

 

The leaking coolant tank is probably why you lost fluid and over heated. Best case you just need to replace the coolant tank and add coolant. A flush would be good but not required. However, depending on how bad you overheated many other things could be damaged. The 2004 were not known for leaking thermostat housings/gaskets. The 2004 were known for leaking coolant expansion tanks.

The expansion tank is easy to replace. The thermostat housing/gasket a little more difficult because of the various items that need to be removed to get to the thermostat.

If you find a good Mini shop, you might want to ask them to give you three different estimates:
1. Replacing the coolant tank and adding fluid.
2. Replacing the coolant tank, flushing the system, and adding coolant.
3. Replacing the coolant tank, theromstat housing/gasket, flush, and coolant.

I would try to find a shop that frequently works on Minis.