Expansion Tank Replacement

[olsonn]

I am about to tackle, what from looking on here, seems to be a common fault on the Z4. I am going to attempt to replace my Expansion tank unit tomorrow on my 2004 E85 Z4. I can find plenty of advice as to what I need to do as regards the top of the tank, but I cant find anything that tells me what I need to do from the bottom, any help, advice or links will be greatly appreciated

 

[GuidoK]

IT's a fault on all bmw's.
It's a fiber plastic tank that in time will crack.

It's a real pain to get off; it's always really stuck on the clips and the o-ring fittings from the base.

Follow the TIS procedure, all you need to know is in there.

 

[AlienZed]

It is a bit awkward, did mine at Xmas, had to get the wife to pull from the top whilst I got underneath and gave it a gentle tap to release it, take your time an be carefull, good luck .
Moz

 

[olsonn]

Well I will give it a go tomorrow, let you know how I get on

 

[GuidoK]

This is the TIS section for the expansion reservoir:

http://workshop-manuals.com/bmw/z_series_e85/z4_3.0i_m54_roadst/2_repair_instructions/17__cooling_system_%28m54%29/11__engine_radiator_with_attachment/4_ra__removing_and_installing_replacing_coolant_expansion_tank_%28m54_n46%29/

(obviously first remove fan cowling and fan and drain coolant)

 

[mac27040]

Tanks is a 5 min job removing from the top.

 

[mac27040]

1. You need to remove the top plastic panel which the expansion cap comes through.
2. if you are working from above only then best to remove radiator fan to give you room, there is a star bolt top left corner nearest the winscreen washer tank holding the fan in place. remove the 2 electrical connectors to the fan. Fan should now slide up.
3. remove top hose
4. remove hose halfway down.
5. remove hose at the bottom. all hoses are on spring clips.
6. there is a screw below the tank to the right, think its another star head.
7. think that's it should be able to slide expansion tank out.
8. I would recommend you check "O" rings in hoses as I replaced mine.
9. fit in reverse order, don't forget you will get a lot of water spillage unless you can catch the coolant.
10. once you have fitted it all back together, don't but large cover panel on until you have bleed the system, there is a plastic screw on top of the expansion tank, open that up and run the car till water comes out. tighten screw and you done. fit panel

 

[GuidoK]

There is also a lock clip you have to remove (that frees up the tank from the base) and the connector for the level sensor .

 

[mac27040]

Installed my new rad and expansion tank today, all from the top. Rad was £33, expansion tank £38

 

[Georgio]

Someone else I know with a Z4 had a pinhole in his expansion tank and when everything got hot coolant used to be forced out all over the shop, seems to be a common fault with the tanks.

 

[wattsie]

This has just happened to my car this weekend.....

Driving home and noticed the temp WAY too high, turned out I have pin hole that pi55es all the coolant out. Tried a few home remedies over the weekend, rubber clamp, araldite etc, but its not working.

Just waiting to hear from the indy how much it is to fit a new tank!

Groan....

 

[w1ndsurfnut]

Olsonn, is your car a manual or auto. Because if it is the auto there is a thermostatic valve under the expansion vessel which sends coolant to the auto gearbox. Its normally shagged as well and will need replacing. i did mine a couple of years ago. Changed the valve just mentioned, expansion vessel, radiator cap, and coolant level sensor. Once i had released everything as previous posts have said, the expansion vessel was a pig to get off. I was able to get something in between the bottom fitting that holds the vessel and then lever it up a little while pulling on the top. Definitely was not a 5 minute job for me. But once done it has been as good as gold ever since.