jtwillia2

Got a low coolant message today and checked under the hood to find the black "nipple" of the expansion tank appears to be cracked (see pics), exposing the metal nipple underneath, but the seal appears to be fine to the actual hose, and I don't think that's where coolant is leaking from.

I guess I would have to replace the expansion tank itself to fix that? Or mend it somehow? Should I even bother?

Thanks

Plutoe

Think about this------a crack any where in a closed loop system typically means that the system is no longer closed and therefore the fluid within the system can leak out---that typically is not good.-----Depending on what crack you are talking about you can buy more or fix the crack--that's another story!! Wada you want to do!!

jtwillia2

Did you even read my OP? I don't think the seal of the "closed loop" has been broken. The metal underneath the plastic is still fine, it's just the black plastic covering that's cracked, and I don't think any fluid is leaking from it.

Plutoe

Well then if you believe the system is leak free---why not simply pressure test the coolant system, you could be correct(leak free) and have a faulty coolant temp sensor!!

Boom vang

I have a 2004 with the same problem, what I think happened is that I leaned in and had my hand supporting me and put a bit too much pressure on the tank and put in a hairline crack. I tried all sorts of epoxies and nothing worked for the long term (not even JB weld), best I found was the epoxy stick that you knead and hardens very quickly and is for good heat. I used it for a stop gap until I pick up a new overflow tank when I take a visit to the US. I ordered an aftermarket one from RM European for $37 made by Behr Hella. The OEM tank in canada is $105 from MB.

In my experience it is the constant issue I have with "German Plastics" the dark black stuff that has a nice texture but over time becomes brittle and fails, eg my engine cover, the small nipples under my post "Attention M271 engines - Maintenance item" and various other plastic parts that seem to break easily over time

jtwillia2

Just ordered a new tank on Amazon. Will probably install in a few days.

VVF

They should start applying the "do not lean" stickers around the engine bay, like "no step" decals on the airplanes LOL

Boom vang

you are so right, I have broken 3 things in my engine bay by leaning my hand on it for support while working on something else. All have been these black german plastic parts