Metal Coolant Tanks??

One cause of the plastic tanks cracking is overpressuring the cooling system from a head gasket leak. Had that happen in my non-turbo '81 diesel, cracked tank and a few ruptured coolant hoses and finally diagnosed the HG poblem. Never had any oil/coolant mixing, only cylinder pressure getting into the cooling system making it run at or near the pressure cap limit. As it got worse, it started causing the rad cap pressure relief valve to open. I also could always hear a slight hissing sound every time I shut off the engine, due to the cooling system pressure venting slowly.

engine, due to the cooling system pressure venting

Roger is right, my 81 NA did this also with blown HG.

I have not seen any manufacturer come out with a plastic overflow tank. I'm not trying to be a d&^k but to me if you have cracked 3 new tanks there has to be too much pressure building up or a VERY hot running engine.

Good luck!! Paul '89 Jetta

Meant to say metal(but you knew that) ;-)

lol, there are some aftermarket catch cans (overflow tanks) that are metal. bout $75 tho for 1 pint.