MrLexse

I had to remove the end tank on the radiator in my 87 S4 (manual) to get to the oil cooler/heater for repair. I got it repaired and thought my troubles were over, but now I'm having trouble getting the plastic tank to pass a pressure test. The seal seems good, but the tank starts to leak as soon as pressure is applied. Is there something I don't know?

deliriousga

Is it the original seal? If so it has probably conformed to the position it was in before you removed it. If it's just a tiny bit off, it'll create little gaps that can be exploited under pressure.

If it is the original seal, I'd replace it before going completely crazy trying to find it.

MrLexse

It is the original seal. Where can I get a replacement seal ? I'll try to replace it before going any further. The tabs are about at the breaking point. I might have one last shot at it.

deliriousga

Now that's a good question. Sorry, I should have checked availability first. I just looked at the big 3 and can't find just the seal. The seal comes with the end-cap piece for $95. You might want to just call or e-mail them to see if anyone has just the seal.

http://www.928gt.com
http://www.928intl.com
http://www.devek.net

slate blue

Not wanting to be the bearer of bad news, but I would say the next thing you will be doing is buying a new radiator. You only get one go at this. So your last chance is to try and reseal as is. That is don't open the tabs up again, they will break off. If you cant do this, go and buy a new radiator, that is what I did last week. Just no way around it and it is also (the radiator)one of those things you need to be 100% reliable. Good luck.

Greg

MrLexse

Arghhhhhhhhhhh. So close and yet so far...

heinrich

Break the end tank if that's what it takes. Then heat the tabs and straighten them. Should be OK.

heinrich

Still need to find a source for the seals. Btw my tanks are on their way to you

marton

I know some radiator shops here that use silicon for classic cars when the tank is so old that the seals are no longer available. No experience of using it myself, maybe somebody here does?

Probably you should try to get 2 seals and do the other tank at the same time while you have the radiator out.

I thought the oil cooler was aluminium and not repairable? Did you fix it somehow or find an alternative cooler that fitted?

MrLexse

I've located a place near me that will repair the oil cooler/heater. If you need yours repaired, PM me. They do high tech govt and military work, and are only dealing with us because the owner is a 928 fan. They repaired mine and it held pressure to my test limit (about 70 lbs.). Risk is yours (if something happens), cost is between $25-50. depending on how long it takes to repair.

Marton- I tried the silicon used for making a gasket, let it set for a couple of days and pressure tested it to 15 lbs.. It leaked immediately-in more than one spot. I used it, in conjunction with the seal, so a different method might work, but I had no confidence in it, so I didn't pursue it. I have removed and reinstalled the plastic end tank four times, bending the tabs each time. They're now real brittle and a few have broken off. This is my last chance (if I can locate/make a seal).
Heinrich-If you find a source, PM me.

marton

I ive in Switzerland in the middle of Europe so I thank you for the offer but I guess it will wotk out a bit dear for me...

I am very impressed that you got the tank off & on 4 times, sorry the silicon seal idea did not work for you.
Maybe if you just take the old seal into a radiator shop or two then they can match it? It is a Behr radiator whi make loads of different radiators and I believe they made several different radiators incuding tank seals for different car manufacturers which are of of suitable sizes - sorry I don`t know the part numbers... but some of the mercedes radiators made by Behr look to be the same size.

MrLexse

Good point, Marton. Thanks for the heads up.

G Man

Hold on a minute! Having been in the radiator business in my earlier days, there is hope. You should be able to go to a good shop that does plastic tank work and get a new gasket. Behr radiators are very common in european cars so parts should be available. If the shop is any good at all they will have a jig that they place the radiator into. Once in the jig even pressure is applied to the entire length of the tank to push it down into the gasket. Once held down tightly the tabs can be bent back over the lip of the tank to hold it down. Trying to crimp the tabs down without having the tank in the clamping jig is not the way to go. I will check at the shop I used to work for to see if gaskets are readily available.

heinrich

Thanks Jim ... we could use a few

marton

I heard another way to get the tanks tight onto the gasket is to use 2 of those wide luggage straps that have some sort of incremental tightening - so you can just crank it up nice and tight before you you bend the tabs.

I did a lot of research here because I planned to do my own tanks but eventually I found a radiator shop that did both my tank seals, cleaned and painted the radiator all for equivalent of 180 US - which is about the price of dinner for 2 here