Radiator repair

[John Larson]

On 2/14/2014 9:29 AM, Radek wrote:
> The leak is in the bond between the plastic top and the aluminum 
> core.  The core is held to the plastic end by U-shaped notches (for 
> the lack of a better term) which I managed to set a little deeper with 
> a punch. This has slowed down the leak.  Has anyone managed to 
> separate the core from the top and bottom ends without destroying 
> something?
>
> Radek.
> 88 90Q
> 91 V8Q 5-sp
>
The important issue here is the inherent fragility of heat cycled 
plastic.  Better radiator shops may have the tools necessary to replace 
the rubber o-ring between the plastic and the aluminum, but the plastic 
may either be eroded or break during the repair process.  In the 40 
years I've worked on Audis, trashed plastic cooling system components 
have become commonplace.  We have seen it in radiators for decades, and 
in water manifolds bolted to heads and blocks as those have replaced the 
metal castings formerly used. What looks like an o-ring failure is 
nearly always disintegrating plastic surrounding the rubber.  My 
advice?  Buy a new radiator and be done with it.  It'll be cheaper in 
the long run.

John