Poor quality expansion tanks

[Roberltd2]

A couple of weeks ago, the low coolant warning light came on and sure enough there was a leak somewhere in the expansion tank area.
Being as this is a well known issue with the Zed 4, I'd bought a replacement off ebay a couple of years ago just in case.
So, when I took the car in to get it fixed, I brought in the £22 ebay expansion tank as well, only to get a phone call from the mechanic an hour or so later to tell me that the new expansion tank was leaking like a sieve which meant the car had to stay in an extra day while he ordered a quality part from the local motor factors and I had to use the bus for commuting home and back in the next day.
Anyway, I got the phone call on the second day to say the car was ready and it was great to have it back again.
The expansion tank which my mechanic had ordered was made by Mahle.
I don't know why I bought the £22 item off ebay really, the advert claimed this, that and the other about OEM quality, being pressure tested etc. etc.
I wouldn't want to name the suppliers but just thought it might be worth relating my experience.

 

[bigwinn]

I find the cheaper ones are a poor fitment issue

Especially on the smaller hose connection

I assume it’s just a cheap knock off issue as I’ve not had it with more premium brands

 

[Bolle]

When I changed my expansion tank I bit the bullet and ordered one from BMW directly. Bit of a rip off at 132 euro, but with the thought that the original OE tank lasted 23 years hopefully I'm good for many years to come. This after reading too many stories of other brands of tanks failing relatively soon. I believe the OE tank I got now is made by Modine.