I have an 07 Mini Cooper that had developed a significant coolant leak under the front bumper on the passenger side. It was leaking enough that I could watch it drip consistently every couple seconds with the vehicle off. The car has 125k kilometres on it and had no other issues. I took it in to the mechanic that the car has been going to for a few years and they told me it needed a new radiator.

Not wanting the expense I decided to try and postpone it by just filling the coolant up regularly and the leak stopped altogether during the next little while.

I’m not very knowledgeable with cars and didn’t understand why it stopped. It has been months since any sign of leaking. I have a few theories and want to know if anyone else has any ideas. Firstly, I went from driving a few times a week to everyday so maybe something got dried out and that is no longer happening? Secondly, it was fall and it got colder out so I quit using the AC (not really sure if or how that’s related.) This was over three months ago and there’s been no leaking since.

If anyone more mechanically inclined has any ideas please let me know. Thanks.

 

Something in the coolant might have clogged the leak(slim chance), but its pretty high pressure in there so maybe the seal at the radiator reseated?

Where was it leaking , do you have pics. My guess when the temp changes it will leak again.

 

It got colder keeping the rubber further in the "temperature gradient" for the elasticity (integrity) of the material. As soon as the spring/summer comes back, it will start leaking again.

 

I don’t have a picture that shows where it is exactly but it’s right under the front bumper almost in line with the left side of lower grill when facing the front of the vehicle. The underside of the bumper is covered in plastic so I can’t see what component it was leaking from. The coolant just dripped out a bolt hole that holds on the plastic underside of the bumper.

 

Hm okay. I thought if anything the issue would have worsened because it can get colder than -30 Celsius where I live maybe causing something to crack and shrink but that didn’t seem to be the case.

 

Rubber when heated becomes more elastic, more stretchy, more loose. If you can find where it is, you might be able to use a Hose Clamp around it to get by. I see a lot of radiator fittings on the mini that are simply friction held over nipples. Every time I change the oil filter and I have to stretch the radiator overfill into a pretzel and it leaks like a sieve. Once I put it back, its' fine. That entire oil filter changing -vs- radiator overfill design had to be designed around October 1 after several long October Fest weekends.

 

I'd buy some dye for leak detection and look for evidence of leaks. Getting caught on the road when it fails is bad. It is just a matter of time before it goes.