Hi Larry,

We tested the old pressure cap and found it failed on the weak side -
not holding any pressure at all.

My mechanic is out of ideas...Suggests we wait for the next thing to break!

I am trying another VW place next week.

>  >
>>  >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).
>
>I am quite certain that your problem was caused by a bad pressure cap that was
>not releasing when it should.  With a working pressure cap, the pressure
>should never build up high enough to cause the repeated damage you describe.
>   It is logical that there is no excessive pressure now if you have recently
>replaced the cap.
>
>Larry A.