The rear heater core is, of course, the plastic core that sits inside
the fan housing under the rear seat, blowing heat to the rear
passengers.

The "differential cooler" is  a metal part on the automatic
transmission that passes coolant through on one side and hot
transmission fluid through the other side. I presume this is to cool
down the AT fluid. It is possible this has another name - I will try
to find out more.

Thanks,
Paul

>Could you be cpecific about what is actualy bursting?
>I think i mentioned before there is more reliable aftermarket trans
>cooler(called Supercooler) that can solve this problem.
>Leon
>85 Subwagen Westy
>
>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

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