I have a 05 s the past few months I have noticed my coolant lvl has been dropping. I normally check fluids once a week or so and around every 2-3 weeks I have to add a little coolant. Not much i have had the same jug for about a year now. It's not over hearing but when I run my ac it sounds like a space ship. My fan sounds like it's working double time.


I have looked around the engine and nothing is leaking (which worries me). There is nothing under the car when it sits over night. I'm hoping this isn't something big. I was thinking could be a head gasket leaking . Any ideas??

 

Have you felt on the bottom side of your coolant tank? They are notorious for leaking.....the oem coolant tank on my 03' Mini just started leaking on me. I noticed that there was some cooling on the head shield that covers up the exhaust manifold.

Do you see any spots on the ground from a leak? If not...could you have a blown head gasket that might be burning the coolant?

 

Look around for white residue....
The leak is so slow...
Could be a pinhole just venting steam....could be ANYWHERE...
A tank, a radiator, a hose, a gasket...I'd suggest you monitor it...keep any eye on it...you will catch it when it gets worse. Any 10+ year old without a leak of some type is called a museum piece....cars leak, drip and do things as they age.
the ac DOES NOT USE ENGINE COOLANT....so if it sounds like a "spaceship"... Not sure what you have going on other than a engine cooling fan issue also... The radiator fan DOES blow air over the ac condenser.... The radiator fan us know to have the resistor fail...resulting in high speed only...making it loud....

 

Check the coolant expansion tank on the back side and under. Then look ate the upper neck on the radiator. Then look under the thermostat housing on the driver side of the engine, while you are there look at the brass sensor right under it, Coolant sensor.

Those are the first key locations to check for a slow leak.

https://www.northamericanmotoring.co...endations.html

 

1. Check the expansion tank. Look carefully to see if it's leaking at the seam. It also can puke out of the cap if you're overfilling it.

2. Check the thermostat housing gasket: they can seep.

3. Check the passenger's side radiator tank, near the bottom. see if there's moisture in the foam or on the top of the splash guard.

 

Yes, definitely. And then check the others that are listed here as well.

Due to an apparent manufacturing defect, the coolant expansion tank on the MINI Cooper tends to leak along the molding seam. Can read more about how to fix it here. If it ends up being something else, check out our other tech articles here to help with a DIY fix.

-Luccia

 

Another vote for checking the expansion tank. They can develop a very slight crack that might be hard to notice. We also offer them at a great price!

check it out:
http://www.minipartsmass.com/partloc...catalogid=8452

You can see the one on the left with the slight crack in the bottle. The one on the right is a new unit.

 

Bear in mind the resistor on the cooling fan is prone to failure also. So usually the fan is supposed to spin slowly and speed up if more cooling is required. If the fan is coming on full speed always then the resistor in the fan is broken.

Secondly, the cooling system can be quite difficult to fill on the MINIs, they love having airlocks. So your system may just be low on coolant and although you've filled it up a couple of times you may just be recovering slowly from an airlock, putting in a little at a time and the air is slowly bleeding out.

 

I had the same problem last summer; it turned out to be the thermostat housing. Had the t-stat replaced and have been fine since, but also recently replaced the coolant expansion tank just in case.

 

I had a similar problem, maddening that I couldn't find it. I went to NAPA and bought some coolant dye (It glows under ultraviolet light. A pet shop will have a UV flashlight because it also shows up pet urine. Don't get A/C dye, it is oil based, coolant dye is water based.), poured it in and went for a drive. That night I went out with the UV light and, pow, there it was.