Cooling system leak (expansion tank?)

[ErrErrminator]

Over the Xmas break I ran my Zed up to temperature only for it to dump coolant all over the drive.

The first thought was expansion tank and upon inspection evidence would suggest that was indeed the case.

Today I managed to wrestle the tank out of the car after a little cussing and cursing. Contrary to my belief that the tank had been replaced before I found it to be original. How it has lasted this long is a wonder.



Having got it out of the car and cleaned it up I can see no signs of splitting or pin holes anywhere. So now I’m wondering if the problem was one of the hose joints. Maybe it’s time to source new o-rings for when it is re-assembled. I have a Meyle expansion tank on order anyway, as a 16 year old expansion tank must be on borrowed time if it is in fact leaking already. I may

 

[kis]

I'm having coolant problems again but mine is probably cracked again... so not leaking a lot. Be interesting to see what you find. Good job with the original tank

 

[Ste sthelens]

O rings pal
Had it on my one

 

[Ste sthelens]

4 got to say when putting back put sum grease on o rings

 

[ErrErrminator]

O rings pal
Had it on my one

Cheers. Did you just get them from BMW, or somewhere else? I assume you can just buy the rings without the pipes?

 

[Ste sthelens]

eBay or u can try local garage????

 

[ph001]

I think it will be the tank, the cracks tend to be hairline so almost impossible to spot. They only leak when under pressure.

 

[ErrErrminator]

I think it will be the tank, the cracks tend to be hairline so almost impossible to spot. They only leak when under pressure.

You’re right. Just thoroughly inspected the tank having cleaned and dried it. No sign, although I was suspicious of a very feint line just above the middle hose connection. I decided to block two of the holes and blow into the third (mmm, tasty) to put just a little pressure in it.



And there it is. The feint line I spotted showed a little moisture.