Replaced my coolant expansion tank less than a year ago......
11-03-2006, 08:46 AM
#1
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Replaced my coolant expansion tank less than a year ago......
still bright white, but it already has stress cracks from the heat!!!! These tanks are real pieces of doo-doo. *rant over*
11-03-2006, 09:03 AM
#4
when my tank cracked and was leaking...
it was made worse when i left one of the mounting screws out...the tank bounces around and it accelerates the cracks' growth.
but yeah, the tanks have issues.
but yeah, the tanks have issues.
11-03-2006, 09:42 AM
#6
Make sure that you have the right conc of coolant in there and it isn't overfilled. Too much water
and/or too much liquid volume in the expansion tank will increase the stress on the tank and cause premature cracking. My OEM one lasted like 30k miles on my S4, about 55k on my B5 Passat (w/ 2.8L 30V ATQ engine). Buy the one (tank) for an A4 or A6 w/ 2.8L 30V engine - it's the same tank just doesn't have the overflow tube and a small, removeable heat shield but you'll save like $20 or more. The part numbers are the same, but the suffix (L or M) dictates these extras that can be swapped off of your bad tank onto the new one and the price is like 1/2 of the S4 specific tank!).
11-03-2006, 09:49 AM
#7
8D0 121 403 L = less expensive part, change the L to an M and you get the S4 part w/ the overflow
tube and the half-dollar sized heat shield. But it will cost you at least $20 more. Other than these 2 small parts, they are identical and these parts can be re-used from the cracked tank. Good way to save some $.
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11-03-2006, 10:45 AM
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Great. I'll probably let it go another year, unless it leaks......
It's not bad, I just would expect more than a year out of it before it starts cracking. The original lasted for 80,0000 miles and I only changed it because it looked bad. It wasn't leaking at all. Thanks for the part numbers.
11-03-2006, 11:21 AM
#9
You're welcome. I only found out about this because I have both an S4 and a B5 Passat w/2.8L 30V
engine. Same part number embossed into both expansion tanks, but the S4 one just has the overflow tube and heat shield (presumably to prevent any overflowing coolant from hitting the hot turbo housing and potentially cracking it). At first, I couldn't figure out why the price differential was so great (~$50 for the S4 one and ~$30 for the Passat one) till I took them both apart. Mine both had cracks but neither one ever leaked - but I figured for $30 why risk getting stranded somewhere and having to be towed if it suddenly ruptured.
