Radiator woes

[Tony Hoffman]

I can tell you for sure running an auto trans with no cooler in a rally
style environment is sure death for it. Just like towing extreme loads with
no external cooler in mountains, that's a sure recepie for trans failure.
Automatic transmissions do not like extreme heat, plain and simple. I don't
know this for sure, but I'd bet the non-cooler 5000 auto's were all with the
smaller (less HP) engines.

We just picked something up at a local hardware store, IIRC. Is this the
little hose that goes to the expansion tank, or one of the big radiator
hoses? If it's a big one, you could try to cut the tube before threading it
in. Do this laterally, in small sections. Then, after threading in, you can
bend some of it over inside to ensure it will stay in there. If it's the
smaller one, obviously you don't have room to do this.

If you remove that part of the old radiator, you will notice it is simply a
piece of tubing, in essence. IOW, it won't do much cooling just being in the
air. Water makes a much better heat bridge than air does. If you know
someone who is good with soldering/brazing you can take some old Ford power
steering lines with the fins on them (also used on some later model VAG
products) and do some loops for cooling, then attach them to the lines you
have, or directly to the trans.

One other thing to consider is this, if you go to an aftermarket external
cooler, you take the burden of transmission heat off the cooling system.
That may or may not come into play under the conditions you are running, but
something to think about. And, as a bonus, with a standard radiator in
there, if something happens, it's easy to source a replacement. Not that any
mechanical or driver failures ever happen in racing ;-)

Tony

On Thu, Aug 11, 2011 at 3:25 AM, Richard van der Hoff <
quattro at rvanderhoff.org.uk> wrote:

> Hi all, thanks for all the suggestions so far. Lots of advice to the effect
> that running the trans without its cooling would be a bad plan - noted,
> although etka sure makes it look like the same trans is used without any
> extra cooling in other models. Still, we don't want to fry the trans halfway
> up an alpine pass, so we won't be doing that :).
>
> For those that queried it, yes on this car the trans fluid comes forward to
> an air-cooled oil cooler which is about the bottom 4cm of the radiator. One
> line goes into the back of the radiator, near the plastic end tank, and the
> other into the bottom of the radiator on the other end. Not sure offhand
> which line is which.
>
> Also plenty of suggestions to get an external oil cooler. Hadn't occurred
> to us tbh, mainly because I think that people just don't 'do' aftermarket
> oil coolers over here (except in racing circles, where they are super-$).
>
> It occurred to us last night that in a pinch, the oil cooler part could
> probably be removed from the bottom of the old radiator, allowing it to be
> mounted elsewhere as an external cooler - with the added bonus that we won't
> need to replace the hoses.
>
> At the moment, however, we're back to looking at trying to repair the old
> rad - probably by threading a bit of piping into the broken section. Tony,
> any idea what you and your friend found to thread in? We've found something
> which is a reasonable fit but could do with being a little tighter - we're
> worried that once the system gets up to pressure, the pipe will come flying
> out again, with consequent coolant and humour failure.
>
> Cheers
>
> Richard