4W4K3

Hey everyone. A couple weeks ago, I purchased an auto '85 928S. I've gone through one tank of gas so far with no issues, driving it almost everyday, while I make a list of things to address on the car. While filling up the second tank of gas, noticed a little puddle of coolant forming beneath the car. I took it home and didn't have any more leaks out in the drive way overnight. Today I rented a pressure tester from the local parts store, compressed the expansion tank to about 5 psi and found a small steam of coolant coming out of the passenger side top of the radiator.

So, I'm looking for a second opinion. I think the radiator's cracked, do you agree? If it is cracked here, is there much else to do aside from replace it?

ammonman

Typical leak point. The hottest coolant enters the rad through that hose. New tanks are available from the 928 vendors and there are a couple of good writeups here on how to replace them. I did both my end tanks almost 10 years ago and everything has been peaches since. THere is also a really nice replacement aluminum rad available from 928 International.

dhallford

Had the same issue last year. Wasted too much money trying to repair the original radiator, with no success. Finally bought a new aluminum radiator. No more radiator issues. Save time a frustrations, order a new one first thing tomorrow.

Gonzotiki_666

Depending on your budget, replace w new 928 Int'l aluminum (~$500) or side tank w gasket (~$100) and have a radiator shop install it (another ~$150). I did option #2 and the rad shop recored my old Behr as well. No leaks & the temp gauge has been in the lower 1/3rd ever since.

4W4K3

Thanks for the info guys. I'm leaning towards the aluminum replacement to avoid further frustration. When you say side tanks, is that referring to an additional section/separate component to the main radiator? Would those "tanks" be included as part of the replacement aluminum unit?

Mark Anderson

4W4K3

Any word on when they'll be in, Mark?

Speedtoys

DO you need new tanks to fix this, or just new seals only?

Mrmerlin

the part thats damaged is the flange.
the plastic in this area is not covered by coolant as an airbubble is living in the top,
thus the plastic gets hot and flexes and the various combustion gases and other chemicals let the plastic work harden,
then it fractures along the top edge. a new seal and passenger end tank will usually restore operation,
best to let the Radiator shop replace the tank

Mrspencer

Just had my radiator done, 85 928s, had the side tanks removed and the radiator rodded, there was a ton of c4ap that came out wich is why the side tank seal gave out, the shop was surprised that the car never overheated, even with my side tank leaking , over 75% blockage, before cleaning, radiator is like new and stock.Mel and sons concord ca.

jeff spahn

You could call Roger and see if he has any new Behr rads. I got a new one from him. I am good for 20 years. My Al one only lasted 7

ROG100

I wish the Behr rads were still available at circa $800. Even from Porsche I had to send 4 back under warranty due to leaks.
I sell the 928 Intl alloy radiator for $595 - I have three in stock.

4W4K3

Thanks for the detailed explanation, Merlin. That really helps to put it into perspective.

So guys, it looks like I might try the tank/seal method first. Is this tank and seal a generic part that a radiator shop would be able to source? This would be my first time working with one on a job like this.

ROG100

Just to echo what Mark at 928 Intl said - the tanks have become hard to find especially with the cooler holes.
They may be NLA from what I have been told by the radiator parts wholesalers.

Mark Anderson

We have just 2 tanks left and both are without cooler holes. I do believe you could use a hole saw and add them but no personal experience here