Diy info

Hello All,
Does anyone have a DIY for installing a expansion tank and the O ring on the tempature sensor? It would be greatly appreciated because I am still trying to eliminate a coolank leak. I replaced the upper expansion hose( thanks Herbp) because it had a small crack on the plastic portion of the hose. This was done Monday and today i checked the tank and it was low( I topped it off with BMW coolant on Monday) and I noticed a minor stream of coolant leaking from the passenger side wheel well. After searching the forum I discovered that a leaking expansion tank and O ring from temp sensor was a poplar issue with the 645.
Thank you for your time and consideration Bimmerfest. I'll PM a few people also if the forum can't help.

Blake

I have to get this done while the weather is still in the 40's so your prompt attention to my request would be hugely appreciated. Funny thing though guys the car never ran hot/overheated and I drove it for at least 1.5 hours before discovering leak. Is there a overflow hose connected to the tank and I possibly over filled the tank? The tank should stiil be filled at the top even after driving for that long correct? Sorry for all the blah . Someone help !

I would like to thank Herbp and Yorgi for all your help with me installing the expansion tank. It to
ok me about 2 hours but I did it. I took the car for a 1 hour drive and came home to inspect for leaks. After the car cooled down i CHECKED AGAIN AND EVERYTHING IS GOOD. After installing the expansion tank I topped off with BMW coolant and I'm good to go.
Thank you,

Glad to see all is well!

Good job.

Hey, Found your post Glad to know the expansion tank worked good

Originally Posted by blakedanatural

Hello All,
Does anyone have a DIY for installing a expansion tank and the O ring on the tempature sensor? It would be greatly appreciated because I am still trying to eliminate a coolank leak. I replaced the upper expansion hose( thanks Herbp) because it had a small crack on the plastic portion of the hose. This was done Monday and today i checked the tank and it was low( I topped it off with BMW coolant on Monday) and I noticed a minor stream of coolant leaking from the passenger side wheel well. After searching the forum I discovered that a leaking expansion tank and O ring from temp sensor was a poplar issue with the 645.
Thank you for your time and consideration Bimmerfest. I'll PM a few people also if the forum can't help.

Blake

I have to get this done while the weather is still in the 40's so your prompt attention to my request would be hugely appreciated. Funny thing though guys the car never ran hot/overheated and I drove it for at least 1.5 hours before discovering leak. Is there a overflow hose connected to the tank and I possibly over filled the tank? The tank should stiil be filled at the top even after driving for that long correct? Sorry for all the blah . Someone help !

I just replaced my Expansion Tank last weekend... It only took me about 20 minutes from start to finish and I didn't need any tools whatsoever. The top and bottom portions of the tank split when the car reaches a certain temperature and you could see coolant spewing down the sides of the black tank. All you have to do is remove the 3 hoses and the electronic connector. I only lost a little bit of coolant during this repair, but I did buy a whole gallon from the dealer as well.