Help with coolant leak please

[V12noise]

Hi Everyone,
I'm new here having just bought a 2010 E70 X5 35d XDrive.
One of the urgent problems facing me is a low coolant level. When I bought it the level was below the Min mark. I asked the owner and he swears he has never had to top it up. As he is a friend, I believe him and I have to assume the problem is new...

Anyway, I topped up the water to the Max mark and after a 25 mile drive it was down to half way between the Max and Min. After not driving the car for 3 days, the level is now down to the Min mark.

So should be easy to find if it is coming out on its own, but I can't see any obvious signs. There are some white marks below the crank pulley, seen from underneath, but that's all I see.

Can anyone make any suggestions of where to look? Btw oil on the dipstick looks black...

[Mistercamp]

Have a 2010 myself. I have had 3-4 leaks over the years and (in my case) every single one was due to a failed oring. Latest was on the cooler thing in the driver side bumper area. That one took me a minute to find as it was not obvious and the last place I checked. In the crank area I would take a good look at the egr cooler and even the orings on both ends. Many people have had issues with the cooler leaking and I believe they have updated that part once or twice. Flashlight, mirror, and a borescope camera would help if you have access. Good luck.

[ard]

cracked coolant overflow is a real tricky one to diagnose. Fluid seems OK...then it is low. But it isnt a constant leak. In fact only when it gets hot, for a short time.




Read this one, to the end...


https://xoutpost.com/bmw-sav-forums/...orking-ac.html


GL

[V12noise]

Thanks for the pointers guys.

There are some traces of liquid on top of the EGR Cooler see pic - might be coolant residue - could it be coming from the black plastic attachment? What's the fix - new o-ring or replace the part?

The expansion tank is on the job list for tomorrow morning

It's along the lines of what I was thinking of in that the water loss happens during the cooling down phase...

Mistercamp, do you have any more info on where to look in the front bumper area - I dont recall seeing any hoses there?

[Mistercamp]

Not letting me upload now than one image for some reason so this will be 2 posts. It's up in this area

[Mistercamp]

There's 2 connections there. Mine was leaking from the bottom, albeit slowly. I really only noticed when doing headlight lens. New oring fixed it although I did have to go to a hydraulic shop since my kit did not have the right size. Also on the topic of expansion tank, they certainly do crack and leak, you will find several posts on here about it. I thought mine had cracked at one point but it turned out to be oring on the bottom of the tank, so I would check that as well if you suspect the tank.


On the egr cooler, yours is different than mine, but I would say it could be either or if it's a descent amount you're losing, probably the 'ribbed' area. I believe that's where they crack and cause a larger leak. Not really sure as I removed mine a while ago.