[E90705]

Coolant Expansion Tank developed a small leak on the bottom near the coolant sensor. It was two bolts up top and two hose clips. I recommend replace the upper hose/tube as well as your there doing it. 30 mins to swap make sure you have towels/rags to soak up the coolant that will spill out after you unplug the bottom hose. Add some 50/50 mix of bmw coolant to top off and another 10-15 mins for the coolant bleed procedure and no leaks!

Part number: 17138616418 coolant expansion tank

Part number: 82142209769 genuine BMW coolant

[oVeRdOsE.]

Originally Posted by E90705

Coolant Expansion Tank developed a small leak on the bottom near the coolant sensor. It was two bolts up top and two hose clips. I recommend replace the upper hose/tube as well as your there doing it. 30 mins to swap make sure you has towels to soak up the coolant that will spill out after you unplug the bottom hose. Add some 50/50 mix of bmw coolant to top off and another 10-15 mins for the coolant bleed procedure and no leaks!

is it a common problem on those n55?

if yes, bmw are kidding or what? this issue is there forever ! still not fixed?

[E90705]

Originally Posted by oVeRdOsE.

is it a common problem on those n55?

if yes, bmw are kidding or what? this issue is there forever ! still not fixed?

These thing tend to fail on every bmw it looks like. It's a good measure of just replacing it if you can.

[rcsup1]

Originally Posted by oVeRdOsE.

is it a common problem on those n55?

if yes, bmw are kidding or what? this issue is there forever ! still not fixed?

I had the same issue and had to replace mine a couple of months ago.

[RL325xi]

Exact same leak location on my 2012 35i with 40k miles.

[Mingstar88]

hey OP, im running into same issue right now. did you have to replace any coolant hoses? you recommend the upper hose / tube, i think you're referencing to 17128651298 - vent hose? thanks

[E90705]

Originally Posted by Mingstar88

hey OP, im running into same issue right now. did you have to replace any coolant hoses? you recommend the upper hose / tube, i think you're referencing to 17128651298 - vent hose? thanks

Yup that is the hose, I replaced this before the actual tank. I'd recommend getting a new one if you haven't yet.


https://www.fcpeuro.com/products/bmw...x3-17127601859

[evilchargerfan]

anyone have a link to a tutorial or video on this?

I looked up the steps in the chilton manual, and it leaves alot to desire:

-"disconnect coolant hoses from expansion tank for coolant" = would be nice to throw up a picture
-over all, just could use more detail
-top off coolant = doesnt tell you how many gals

[Wgosma]

Here is the procedure shown in the BMW TIS (Tech Info System); this is the workshop reference that BMW technicians use as a guide- so it presumes a trained technician can do the job using these instructions.

This looks pretty simple to do, but I've done this type of thing on my cars in the past so have bit of experience.

TIS link: https://www.newtis.info/tisv2/a/en/f...rts/1VnYm43pwu

[evilchargerfan]

thanks for the link Wgosma , really detailed and helpful


for those of us who do not own a "Vacuum filler device" tool, is there another poor mans way to propertly bleed / fill coolant?

[Wgosma]

Fill: just add the coolant mix rather slowly into the expansion tank, that will work.

Run the bleed cycle to insure any entrapped air is out of the system.

[anjuna]

LPT - remove the top hose on the expansion tank and let the water pump run to empty the old expansion tank while pumping the coolant from the top line into a spare jug.

Install expansion tank.

Fill expansion tank, let water pump run. Add fluid as necessary.

The expansion tank is one of the highest locations on the vehicle. Leave the cap off and let the pump run. All the air will bleed out.

[Marty in NY]

Originally Posted by evilchargerfan

thanks for the link Wgosma , really detailed and helpful

for those of us who do not own a "Vacuum filler device" tool, is there another poor mans way to propertly bleed / fill coolant?

Right, I don't have any fancy tools either. I fill the tank slowly, all the way up. I know there's going to be air in the system so I pull the front of the car onto ramps to get the front end up and then let it run while watching the coolant temp, just to be sure it doesn't get too high and let it run till it warms up a bit. Then shut it off and open the reservoir to let the air out. Continue that process, take 10-15 min till you are done. Then drive the car for a day or so while watching the water temp and then bleed it again in the same manner, fill up the reservoir to make up for any air that you let out. If when driving the car you see the temp rise above where it has always been, mostly dead center, that means there's air in the line and it need bled again.

[pungo]

Follow this procedure if you don't have the vacuum equipment: X3 coolantbleed.pdf.

[evilchargerfan]

Overwhelming responses everyone.

I really appreciate the community we've got here. Will take into account everyone's input. Wish me luck!

[Marty in NY]

Originally Posted by evilchargerfan

Overwhelming responses everyone.

I really appreciate the community we've got here. Will take into account everyone's input. Wish me luck!

No man is an island, we need others!

[Mingstar88]

Originally Posted by E90705

Yup that is the hose, I replaced this before the actual tank. I'd recommend getting a new one if you haven't yet.


https://www.fcpeuro.com/products/bmw...x3-17127601859

just to followup. replaced mine today. i didnt remove my filter box, made it more difficult than needed.
old tank: