Compression test yes,
but more than that, for something that can be terminal,
oil pressure.
As with a gauge ..
If you start seeing lowish oil pressure at say 60mph ..
or a very low hot idle oil pressure ..
then you start to be concerned.
Driven long enough with pretty low oil pressure ...
   sometimes a rod likes to go through the engine case.
2.1's are more prone to this
1.9's have a bottom  end that seems to hang in there forever.
  I have one that runs fine, but oil pressure light is on anytime it's
warmed up and rpm is below 1,500.

what fun,
scott
www.turbovans.com

On 5/8/2012 3:55 AM, Robert Clemmer wrote:
> My young 91 has 242K and also has never been opened up other than for a head
> reseal about 14 years ago.  I just ran a 1000 mile non-stop trip back from
> FL in 90+ degree weather and it too was smooth as silk.  It consumes no more
> oil now than it did when it was new 21 years ago.  How long will it last, I
> don't know but I have no reservations on taking this bus anywhere.
>
> Bob
> Perkasie, PA
> 91 Auto WBX
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Richard Koerner
> Sent: Monday, May 07, 2012 6:45 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Best way to judge life left in Waterboxer?
>
> The 1.9 engine in my 85 manual Vanagon has 198,000 miles.  Never been opened
> for any reason.  Runs smooth as silk.  Gentle driving, burns no oil, always
> passes smog, power seems about the same as always.  Wondering how long this
> thing can last?  What's the best way to get some idea, compression test?
>
> Rich
> San Diego
>