dbarahona

Hi to all,
I went out on vacation for 15 days and wen I came back today I noticed that all the coolant ( or at least a big amount) of my 2007 BMW 535i with 70,000 miles was all over the floor...I looked every were but l can't seem to find the origin. Have any one experience something like this?
I was not having issues with loosing coolant before.


Thanks.

e6t.lab.rat

Check your expansion tank - the black container you fill with coolant. It's a common problem with it cracking.

pcy

2007 535i ?

Are you absolutely sure it's the coolant [and not windshield washer fluid]?

If it is indeed coolant, check the usual suspects - coolant tank, radiator petcock valve, radiator itself, lower radiator hose, return hose, etc.

Check if there is water in the windshield washer fluid tank.

Hyper_545i

Weird, I just had the same issue on my 545i. Tis the season I guess. As the car was sitting for a week and a half, I was unable to determine where the leak was coming from. I replaced the usual suspects, the coolant expansion tank, cap and vent pipe that runs along the radiator and then bled the system. I had to add almost a gallon of BMW Coolant / Distilled Water 50/50 Mix.

I started the car back up and let it run to operating temperature. I allowed the car to cool down for 4 hours and found it was still leaking. Fortunately I was now able to see where the leak was coming from. It was coming from the Coolant Temp Sensor on the lower radiator pipe. I'm sure after 10 years and 106K the O-Ring has all but shriveled up. I have one on order and it should be here today. I'm hoping that finally fixes the leak. Good luck OP. Keep us posted.

yelcab2

My experience with BMW Plastic radiator is that they die after 100,000 miles in unpredictable fashion. I would just replace the radiator before it strands you someplace, or ruin your engine.

e6t.lab.rat

Lol. Same problem here. I couldn't believe how difficult it was to find a replacement Oring. No one locally had it! BMW would only sell you the sensor of course. I found I had some spare orings from an AC kit I had and managed to squeeze one on there, and that did the trick.

Hyper_545i

I was going to try to find an O-Ring and just swap it out. With my luck the Coolant Temp Sensor would fail the next day and I would have to do it all over again. LOL!

I am going to try to replace without draining the system. I think member Health Services said it could be done if your quick enough. Fingers crossed!

KyleB

BMW E60 radiator = all aluminum.

Unless you've confirmed that the radiator is the failed component, just 'throwing' a radiator in the car isn't going to do much good.

KyleB

I don't know where that sensor is located on your V8, but I tried to do what you're suggesting in my M54 powered car and I turned my garage into a swimming pool Maybe if you have quick hands you can pull it off, I wasn't so lucky (or skilled).

Good luck!

Hyper_545i

I got lucky. Didn't lose more than a few drops of coolant. The key is the engine has to be cold and you cannot open the coolant reservoir cap. I had the car sitting for a few days in preparation. No more leaks......for now.