Have an 06 MC w/41000 miles and have noticed a puddle of what appears to be water forming under the engine compartment after I park for any length of time. The fluid is not oil (dipstick reads full), is colorless and odorless, and has no smell of antifreeze associated with it (coolant resevoir is fine). The puddle is approximately 10"x6". It shows up when I park in my unheated garage or in an open parking lot.

This has been going on for at least a month and I have noticed no problems with the car with respect to starting, engine noises, or overheating. I suspect condensation from the HVAC system(? forgive my ignorance on this one), but I am not certain. Has anyone else seen this.

If this is just water, 1.) where is it coming from, 2.) what is causing it, 3.) is it going to cause something to break, and 4.) should I get to the dealer sooner than later.

Again, forgive my ignorance and any input would be appreciated.

 

If the humidity is up in your area, and you've been using the AC or defroster functions, it could well be condensation from the AC unit. All of the fluids used in the car have a unique smell/feel/look that makes them reasonably easy to identify. Occam's Razor applies.

 

what they said

 

If you're not losing any vital fluids, then it is either condensation from your HVAC (most likely and very common) or from an exhaust leak (water is a by-product of combustion).
Greg

 

I was going to suggest that you check your engine mount, but since it's colorless and odorless, I'll have to agree that it's probably condensation.

 

Hopefully it is just your AC but it is unusual that you had not noticed AC condenstation before 40,000 miles because I always get a AC puddle when I use the AC.

When my 2006 MCS thermostat housing started to leak at 25,000 miles, it was difficult to tell that it was coolant. Eventually the leak got bad enough that it was noticable that the coolant level was going down. I would closely monitor your coolant level.

 

If it is coolant, the "water" won't evaporate, while condensation will.

 

I just had the thermostat replaced (cracked housing) on my 2007 MINI Cabrio Monday. Symptoms began with a small puddle under the front of the car...very sporadic, maybe 3 or 4 times (that I noticed) in 5 months...did not appear to be antifreeze....would check each time and none of the fluid levels were low. Then last week, a fan started running for a few minutes after I would turn off the car. I checked the coolant level and it was low...added coolant. Then the car tried to overheat on Friday. I took it in to the dealership on Monday and it was the thermostat. Like QUIKMNI said, monitor your coolant!!!

 

If it's A/C condensate (water), it will evaporate quickly. If it's coolant, it might take a couple of days.

I have a recent and unsolved leak in my '05 MCS that's definitely coolant (bright green). I've had to add a little water to the resevoir. I noticed that the coolant doesn't have the smell that old-style coolants had. It does feel a little greasy or slippery, unlike water.