I think (hope) we solved the coolant leak mystery on our E53

[E53inLA]

About a year ago, we replaced upper and lower radiator hoses. In the lower hose there's a temp switch with a small green O ring to make the seal. Autohaus part #13621433077.

Past few months we'd get a low coolant level message every few weeks, and I'd top it off, but never any drips in the driveway. This past weekend it finally started dripping. A couple wraps of teflon tape around that green O ring seems to solve the problem. I will order replacement part with the next order.

[nezarnuaimat]

Just add some fine-ground black pepper to the coolant fluid

[E53inLA]

Originally Posted by nezarnuaimat

Just add some fine-ground black pepper to the coolant fluid

I'm 99.99% sure the intended use of Teflon tape (found in the plumbing dept at hardware store) is to create water tight connections, whereas...

I'm thinking the intended use of ground black peppercorns... is something completely different.

I did a Google search for pepper in coolant, and there are a number of articles that describe using this as a temporary fix, when one is in a pinch, however I'm not ready to buy into this as a permanent fix, no way. OTOH, when it comes to the proper way to fix a nice rare steak, I'm all for it!

[sshu]

Thanks for the good wishes on the new addition to our family. Another day in the life of owning a X5 right? Our X5 is doing fine but now my M5 has a VANOS isssue, I'm going to take it to my mechanic in a few weeks, I just hope it's an easy fix.

[ArtMan]

Originally Posted by E53inLA

About a year ago, we replaced upper and lower radiator hoses. In the lower hose there's a temp switch with a small green O ring to make the seal. Autohaus part #13621433077.

Past few months we'd get a low coolant level message every few weeks, and I'd top it off, but never any drips in the driveway. This past weekend it finally started dripping. A couple wraps of teflon tape around that green O ring seems to solve the problem. I will order replacement part with the next order.

Well its not the sensor thats broken its the stupid o ring....I took 3 smaller o rings and put them in and all made the same size as the one o ring....so far i have not found the same size o ring..... but my problem has been solved no leaks nothing its been over a month now....

[E53inLA]

Originally Posted by sshu

Thanks for the good wishes on the new addition to our family. Another day in the life of owning a X5 right? Our X5 is doing fine but now my M5 has a VANOS isssue, I'm going to take it to my mechanic in a few weeks, I just hope it's an easy fix.

Well it certainly brings new meaning to the old adage "Baby needs a new pair of sshus!"

Hope you aren't loosing too much sleep over the new baby, and to put things in proper perspective... no beemer is worth losing sleep over.

[E53inLA]

Originally Posted by ArtMan

Well its not the sensor thats broken its the stupid o ring....I took 3 smaller o rings and put them in and all made the same size as the one o ring....so far i have not found the same size o ring..... but my problem has been solved no leaks nothing its been over a month now....

+1, however the new part is only $16, which is much less costly than having the wife have a serious breakdown

[ArtMan]

Originally Posted by E53inLA

+1, however the new part is only $16, which is much less costly than having the wife have a serious breakdown

No your right, i was just to far from home when i noticed the leak and like an idiot i unplugged it and took it out to see and bam the or ring crumbled and good thing i was near a autoparts store so i bought a generic o ring set and used 3 small ones to make a nice fit for the time being.... but yea ive also placed an order for the sensor. I do wish we could just but the oring i hate replacing a working part just cus of the oring. Any how better safe then sorry.

[steelheader]

I had the same problem after doing the timing chain .That dam oring -just started leaking and when you take the sensor out the new anti freeze would come out I just used a thicker a/c oring and has been doing good for 5000 mile s .Now I have a slow leak around the alternator what a pain in the ass!!!! always little bs!!!!!!!!!!!P.s they have a kit at napa You can match it up .

[Diggerdugout]

I had a similar problem recently, 'check coolant' message starts about a week after topping up. It turned out to be a 5cm vertical hair crack in the wall of the expansion container. I couldn't see it until the service guy filled the removed container with water, squeezed the sides and you could see a bead of water appear. Apparently its a common problem. They had previously replaced seals and done a pressure test.