Hello,

It's about my 2008 MCS. It's been 10 days since they topped the coolant off, but the level seems to be lowered again. I have attached the picture (sorry the quality) and as you can see the red line is "MIN" line and coolant is below the red line.

The car running is okay I don't smell anything so I don't know who ate the coolant. Any opinion?

Thanks in advance.

 

There are really only 3 possible options. Ranked in order of bad to worse.

1. It's leaking somewhere. Check for puddles under the car when the car is sitting for a while, look for dripping/spraying when the car is running. It could also be leaking inside the cabin. Look for a wet floor rug. Antifreeze smells sweet.

2. It's being blown out of the overflow line. This would most likely be due to overheating of your engine. Top off the coolant, run the car normally and check the tank. If you have more coolant in your tank than normal, check for engine overheating.

3. Blown head gasket or some other internal leak causing the coolant to be vaporized and sent down the exhaust pipe. Coolant burned in sufficient quantities will show up as white clouds of exhaust smoke that might smell slightly sweet. This would be the worst (and most expensive) situation.

Be careful around the hot engine. If the radiator is too hot to touch, don't take the cap off.

Good luck!

 

I believe thermostat gasket leaks are common. Look for a small puddle of coolant under the car when it sits overnight.

 

Thanks much jgohlke, trwxxa.

I don't remember that I saw puddles under the car or not recently. And I will drop by the MINI service due to the service (I think front brake) and I will ask them about this issue. Hope it is not an internal leak.

 

I had a cracked thermostat housing, which has come up around here a few times- it lost so little over such a long time that it evaporated long before I ever saw it.

Luckily it was a very slow leak until it gave way all at once, and the liter of coolant in the parking lot at work was very obvious.

 

Isn't it still under warranty? Let the dealer figure it out...

 

we have a winner

 

I have been loosing coolant in my car for a number of months, I never detected any leaks.

Yesterday the dealer repaired a leaking o-ring at the temperature sender.

 

My vote is a cracked thermostat housing as it happened to me. Let the dealer repair it.

 

My 09 does the same thing. No puddles. It's a very slow loss. I've looked for the white crusty's, but have found nothing.

 

Thanks much and I will update later if they repair something, but I have to wait one more week.

 

Mine looks a little low, too. Will confirm overnight. Does the MINI require a specific anti-freeze/coolant formulation or will Prestone do?

 

I remember someone said that if we don't use OEM coolant then may have the water pump problem (I could not find the post again though). So I usually drop by the dealer so they can top off the coolant.

 

I went to dealer to check the "Service" and coolant leak. The "Service" was brake fluid not pads though (they said front pads at 6mm so I have to wait until minimum 3mm).

The coolant leak, they said that the coolant tank cap not secured properly -- I never touched it actually they touched it about 15 days ago -- and they did pressure tested cooling system and it was okay.

Actually I don't think the problem was the tank cap because it's been 3 times (include this time) topped it off from them, but they said it's okay from testing. I think I need to check more often the coolant tank.

 

I've had a similar issue and brought it up with my dealer when I went in for a CEL today. Turns out I'm getting a new thermostat, so perhaps it's the same for you. I'm not sure if it's the gasket, housing or what yet.

 

I had a similar issue to you (no leaking or puddles of coolant under the car), but my coolant did not go that low. It was about 1cm below minimum. They did a pressure test and found out the culprit was the thermostat itself. They said the thermostat housing was fine but replaced the thermostat. I would keep an eye on it, and if it keeps on getting lower, try a different dealer.

 

My coolant is so far so good since they did pressure tested cooling system. I check coolant level once a week and it's good so hope there is no problem.

 

One note on the antifreeze... get the BMW-certified brand. To my knowledge, it's the only one that has that unique dark turquoise color. Some may claim you can mix different brands of antifreeze; I don't do it. I bought a gallon of it about two years ago for about $20. Yes, it's pricy. But it does make two gallons when mixed 50/50, and I have only used about 1/3 of the first gallon since then.