Hi Mark,

I didn't even know I had a differential cooler until the first one
broke. Someone correct me if I am wrong, but I believe this part is
only on the automatic transmission. It passes the transmission fluid
through a thin metal part with the coolant on the other side (I
presume to cool the transmission fluid).

I have never changed the pressure cap on my expansion tank on a
regular basis, but it might be a good idea, or else to have it tested
yearly. (I do the coolant yearly, the brake fluid every other year).

I hope to know more next week - will post the mechanic's finding for
everyone. I tried to get into another mechanic, but there is a two
week wait, and I can't do without the car, so I am giving him the
suggestions from vanagon.com members...

Paul

>Are we supposed to provide any maintainance/inspection for our
>differential coolers?
>
>>From: Paul Cavanaugh <phonyexpress@IWAYNET.NET>
>>Reply-To: Paul Cavanaugh <phonyexpress@IWAYNET.NET>
>>To: vanagon@GERRY.VANAGON.COM
>>Subject: Re: 4th heater core burst in 1 year!
>>Date: Thu, 28 Jun 2001 23:25:11 -0400
>>
>>Hi Mike,
>>
>>Thanks for the hose-check suggestion. I have suspected poor
>>circulation through the radiator, as the high speed fan kicks on at
>>McDonald's on pretty cool days.
>>
>>Will also check out David's pressure cap test.
>>
>>I am especially freaked out about the differential cooler, as this
>>failure caused coolant to go into my transmission (as well as trans
>>fluid into my cooling system).
>>
>>My mechanic still has the part at his shop - I may go back and look
>>at it. I suppose it's possible that the leak occurred "around" the
>>gaskets, rather than through the metal????
>>
>>I was thinking about excessive heat. Maybe having the thermostat
>>checked too, but I remember I had a new one last winter (half way
>>into this big mess).
>>
>>Thanks!
>>Paul
>>
>>
>>
>>
>>>Could you possibly have a crimped hose or tube somewhere that's causing
>>>undo pressure in the system?  Maybe you should trace all the hoses and
>>>make sure.  Sounds like a real drag!
>>>
>>>                                                             Mike G.
>>>
>>>Paul Cavanaugh wrote:
>>>
>>>>  My 1990 (180k miles) GL automatic just had it's 4th rear heater core
>>>>  burst in 12 months!
>>>>
>>>>  It also has burst two (metal) differential coolers, flooding coolant
>>>>  into and ruining my transmission.
>>>>
>>>>  Any ideas what could be happening?
>>>>
>>>>  My friends are urging my to give up the car (and I am tired of
>>>>  pulling up the flooded carpet)!
>>>>
>>>>  Thanks!
>>>>  Paul
>>
>>--
>>'90 Vanagon (180k)
>>'84 Vanagon (217k)
>>'78 Microbus (175k)
>
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