Had my JCW Clubman in for what will likely be the last of the free maintenance I'll get on it.

Don't know if this happened because I asked about a coolant flush under the maintenance plan (which they told me, of course, was not included, since the coolant is 'lifetime' ), or whether some summer hire got a little over-zealous with the fluid top-offs, but when I got back home after picking it up, I noticed that the coolant reservoir (which had been properly filled right to the "MAX" indicator when I dropped off the vehicle) was now nearly filled to the top -- to just under the return line hose, such that there was only a small air pocket in the top of the reservoir.

Checked the Owner's Manual; of course it states (pp. 108-109 in the 2009 version) that the correct level is between the "MIN" and "MAX" indicators, but also states "do not overfill" if you need to add coolant.

I'm guessing that's primarily to avoid overflow when opening the reservoir cap, but since the system is pressurized and fluid is incompressible, is there any danger of damage, either to the coolant system, seals/gaskets, or engine? Is there an overflow/relief valve that I'm just not seeing on the reservoir? As I said, there is still a small pocket of air in the reservoir; there are no leaks (at least for the moment); and I'm guessing that the reservoir itself or the return line would fail first if an over-pressure situation developed...?

The vehicle needs to go back for a few minor warranty items (warped hood scoop and some items related to the vacuum system) when the parts get in after the Fourth. I plan to have them remove the excess coolant at that time, but is it OK to drive in the meanwhile (or at least 15 miles back to the dealer)? I obviously don't want to risk damaging anything, so I'm content to leave it parked until then...

 

Just like any other car, if pressure builds up too much the cap is designed to release the pressure and dump coolant outside. You can see the smaller hose coming out of the reservoir, that's the dump line. Your car will be fine.

 

Thanks, Ben. Good to know!

 

Good to hear an owner checking their fluids themselves!!!
Never trust a dealer....mistakes happen!!

 

Exactly why I check! I've heard too many horror stories about replacement fluids that had been forgotten during servicing, etc.

I was actually under the bonnet primarily to check the oil level, since I'd just received an annual, low-mileage change. Glanced over at the coolant reservoir and went ...

I'm now considering just siphoning the excess (maybe a cup or so) out of the reservoir myself using a turkey baster or other such device, then holding on to it should I ever need to top off the reservoir. Not sure what the implications of 'reusing' coolant are, though. Whatever little bit they added is now probably well mixed into the original 'lifetime' coolant, which itself is about 3 years old, so I'm not sure whether that's a really sound plan. Opinions...?

What's nearly certain, now that my maintenance plan has about run its course, is if I have them remove it, and I ever need a little in the future, I'd probably have to buy it back from them... Guess it all depends on how generous the service guys at the dealership are feeling on any particular day...

 

I think it is safe to say that a "lifetime" fluid has not been made that is truely that good....good for the warrenty period perhaps..beyond that, owner/user beware...and I have never heard of a lifetime engine coolant.....long life yes....lifetime no....
heck bmw/mini blue coolant is pretty short lived..3-4 years.....many other makers have moved on th newer types of coolant....that may not be better, but does have a longer life.

 

Yeah, that's kind-of my read on the whole 'lifetime' fluid thing as well: it means the fluid will last for its lifetime... And so the question then becomes: what, realistically, is the expected in-service lifespan of BMW/MINI coolant...?

 

Just finished extracting the excess from the coolant reservoir. Seems my previous estimate (about a cup overfill) was off -- by about half...! Sixteen ounces siphoned out to put the level back at "MAX" -- and now stored for future use, should I ever need some to top off the system...

Whoever put it back on really torqued down the reservoir cap, too; I was a bit concerned that I'd break it getting it off...!