Coolant leak expansion tank

[Zaks]

I did a bunch of research but aside from the cracking expansion tanks (which is not my issue) I couldn't really find what I was looking for... I noticed a leak a few months back and just a few days ago decided to remove the intake and see what's going on. Looks like my expansion tank is leaking from the bottom 2 connections. A reputable mechanic replaces the whole cooling system early last year and about 10-11k miles ago. Not knowing of the aftermarket tank issues until recently, I bought the Meyle tank when we did the cooling system.

Long story short, I'm wondering if this seems like a Mayle exp tank issue (bad oring or angle a bit off) or install error? Seems like it's slightly angled, that is the bottom of the tank connections are slightly toward the engine instead of 100% vertical.

Thoughts?







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[slater]

bad (flattened) o-ring on one of those two ports - looks like the smaller one. i've seen this before - on a 6-month old behr expansion tank, too.

you can buy new o-rings (aftermarket), but i would just replace the tank.

[Zaks]

bad (flattened) o-ring on one of those two ports - looks like the smaller one. i've seen this before - on a 6-month old behr expansion tank, too.

you can buy new o-rings (aftermarket), but i would just replace the tank.

With a BMW tank I assume? Is it better fitment or oring quality?


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[az3579]

With a BMW tank I assume? Is it better fitment or oring quality?


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Fitment is always perfect with OE parts, so you can rest easy knowing that. Quality... well, unfortunately I don't think any of the tanks are good enough to not explode at some point. I think the OE is the best you can get, and even that is lacking.

[slater]

Fitment is always perfect with OE parts, so you can rest easy knowing that. Quality... well, unfortunately I don't think any of the tanks are good enough to not explode at some point. I think the OE is the best you can get, and even that is lacking.

yeah. the behr/hella tank felt as nice as an OEM one (made by modine), but it's made in china... you really need to look at where stuff is made. i normally wouldn't buy febi/bilstein parts, but just last night i replaced front control arms, FCABs, swaybar endlinks and tie rods on a friend's E46 325iT and i used febi/bilstein stuff, and it was all made in germany. nice quality stuff. i used the 'ZHP' arms, curious to see how they feel tonight when i get it all buttoned back up and go for a test drive.

[ryankokesh]

Can you weld? Could always make yourself a non-exploding steel version