> 
> 
> I just read a post from someone who mentioned the 'evils' of 10w40 oil 
> used in their bus.  Are these perceived 'evils' only a problem in air 
> cooled engines or is there something basically wrong with 10w40 altogether?
>

That was me.  I heard (on the VintagVW list I believe, maybe rec.autos.vw)
that the polymers that they use in 10W40 break down readily under heat and
that, in fact, auto manufacturers have stopped recommending its use.  My
personal experience would verify the first part of that statement and, if I
remember right, the owners manual for my `85 RX-7 doesn't include 10W40 in its
range of temps/oil weights.

Isn't there an oil FAQ that somebody on rec.autos put together?  I seem to
remember occasionally seeing a huge oil dissertation on rec.autos.vw.
(Did I save a copy of that...?)

> I've got an 86 Vanagon, have used 10w40 for all the time I've owned it 
> and haven't had any problems whatsoever. BUT... I don't have an oil 
> pressure gauge, I'll I have is one of those idiot lights, thus I haven't 
> the faintist idea what the pressure reads under certain conditions.
> 
> I use 10w40 in both the Vanagon and my '78 Scirocco, which I've owned 
> since it was new. Is there an advantage to using 20-50?
> 

I expect that the problem would be a lot worse in an aircooled engine since 
they get hotter.  I imagine that, with frequent oil changes, there'd be no
problem using 10W40 in a waterboiler except for the obsessive amongst us!

John Ritchie
ritchiej@ucs.orst.edu