Hi Ian,

No excessive temperature here.

When this all started, I just blamed heater core, t-fitting, and
plastic distribution piece on 10 year old plastic. The 2nd core I
blamed on the 1st one being defective.

It still is possible the differential cooler is a separate problem,
though it all sounds like some kind of pressure buildup to me.

Not sure what to do now - I have an appointment with the top VW place
in town (they run a couple weeks behind). Hope they can find
something.

Thanks,
Paul

>Paul,
>
>I wish I had some fantastic idea for you, but my enthusiasm was dented
>today, when another hose split, this time requiring putting Veronika on a
>truck to the mechanics. It poured out quicker than I could replace it! I
>guess I'm going to have to replace the entire system as a precaution. Oh
>well, she needed servicing anyway.
>
>What is the climate where you are?  I was wondering if excessive heat
>might contribute to these problems? I have  regularly traveled all day in
>temps over 100f. (with no overheating)  I wonder if  this causes fatigue
>or stress over time.  This morning was frosty. May have something to do
>with it?
>
>Any theories anyone?
>
>Take care + have fun,
>Ian
>
>Paul Cavanaugh wrote:
>
>>  Well, the mystery continues...
>>
>>  My mechanic tested the coolant (while the engine was both hot and
>>  cold) for traces of combustion leakage (hydrocarbons in the cooling
>>  system) and found nothing.
>>
>>  He also found no excessive pressure in the oooling system (I replaced
>>  the expansion tank pressure cap 2 weeks ago, just to be safe).
>>
>>  No explanation for 4 rear heater cores and 2 differential coolers
>>  bursting in one year!
>>
>>  He is suggesting it could this be an intermittent problem??? I don't
>>  want to lose another transmission!
>>
>>  Any ideas from my Vanagon.com friends would be welcome.
>>
>>  Thanks,
>>  Paul