E39 expansion cooling tank leaking. (99 528i)

[jericho111]

Hello everybody!

Pls. help/advice... Just saw cooling expansion tank to the radiator leaking near the top cover. this is the cooling tank connected to the radiator...

It does not leak totally.. no leaks from the radiator only that expansion tank. i can say more than half of the coolant i put leaks. No real issues and temp stays half where no problems with idling or anything mysterious..

Can i use the car until i get that cooling tank? i ordered it today but should get here in a week. Could anybody give me tips on how to replace the expansion coolant tank?

Thank you my friends and More power to us.

jericho

[brettski]

I'd be very cautious about how much/far you are driving in this situation. Your cooling system isn't operating as its designed, so the boiling point will be lower (no pressure to raise the boiling point), the coolant will be leaking constantly, and its really easy (read expensive) to get it wrong.

Changing the expansion tank in not a difficult task, you'll probably want to remove the air filter box so that you have access to the lowed hoses and level sensor connectors. you'll also need to remove the air purging screw and the plastic clips that hold the radiator shroud in place. After that the bottle is pretty simple to remove. Have plug of some sort that you can insert into the lower hose to reduce how much coolant you lose in this process. Make sure that you don't kink the small hose that goes to the expansion tank via the bleeder screw.
Once you have it all changed over, set the car on a incline (Nose up) and add the coolant with the engine running & heater on max, once the expansion tank level stops dropping put the cap back on and go for a drive. Keep checking the expansion tank level for the next few days to make sure no big air pockets have been hiding in your cooling system and have dropped the level.

[jericho111]

Hey Brettski!

Thanks for the tip my friend. I just won't use the car till the replacement arrives.
Thanks again and I agree with you totally.

Jericho

[brettski]

I think that is a wise choice if you can manage it.
Let us know how you go with the changeover of the expansion tank. When you remove the bleeding screw, there is a plastic surround that you need to also remove, that surround is usually held in place with two plastic tabs.
The rest of it is pretty straight forward. The other thing that may bring you undone is the low coolant sensor, depending on the version that you have, it may be brittle and easily broken when you remove it from the expansion tank, so don't get too heavy handed with it.

[jericho111]

Had the expansion tank (Bottle) replaced at the shop and discovered too that my upper radiator hose and expansion tank cap needs to be changed as well. Now my car cooling system is working very well as all leaks were fixed. Wooohh!!!

[brettski]

And now you are free to use your car as it should be. Better safe than sorry.

[Jack Dabsy]

Happy days!!
Another satisfied member Brett !!!

[jericho111]

Thanks again for the great tips.... More Power to US!!!

[brettski]

Go on to enjoy your ride.