FW: Mobil DTE-13M

[Livolsi, Stephane]

I also did some research on 'alternatives' and I found there are some
hydraulic oils out there that come very close to the Audi specs for G002000,
EXCEPT in 1 area- the viscosity index.  This is a measure of the oils
resistance to change it's viscosity over a wide termperature range - ie does
it thicken up when cold, and thin out when hot.

The Pentosin brand oil has an extremely high viscosity index (340), compared
to any and all other hydraulic oils I was able to find.  This means it has
close to the same viscosity at -20 as it does at 100 degrees (just grabbing
#'s out of a hat here)
The viscosity index of Mobil DTE 13M for example is 140.  Is this
significant and important?  I don't know but I suspect it probably has
something to do with the cost of Pentosin because no other brand even comes
close.  I think I may have found a 210, but then it was way out of whack on
some other specs
....
The local Imperial Oil people have suggested Esso Univis N32 as an
alternative to Mobil DTE 13M (I'm in rural Canada, the Esso stuff is more
available than Mobil stuff)
Guess what?  The specs for Univis N32 are virtually identical to Mobil DTE
13M - give or take a degree here or there.  The spec sheet for Univis
states, and I quote "The high viscosity index values can be seen in the
typical properties section"  --I looked it up and it is 160.  Man, these
guys would freak if they ever found out about Pentosin and what a 'high'
viscosity index really is!

Now here is where the real world hands on experience comes in.  I live in
logging country and we have equipment here that will grab a huge tree, cut
it down, swing it around while ripping all the branches off and then pile it
nicely on the logging trucks.  And all this at a speed that makes you dizzy
if you watch too long.  These things are running very high pressure, extreme
service hydraulic systems full of Esso, Shell, Mobil - whatever, but I can
guarantee it isn't Pentosin!  A very important consideration is that these
machines probably run a different hydraulic oil for winter, than in summer -
this may allow them to get away with using a lower viscosity index oil.

For me the biggest argument FOR using a Pentosin substitute is that there is
no way that my little hydraulic system boosting my brakes and steering is
seeing more severe service than these logging machines. NO....bloody....way!
So if DTE 13M or Univis N32 can run in those machines, why can't they run in
mine?

Just for the record, I am planning a complete rebuild of my 86 5ktq
hydraulic system - pump, bomb, rack, hoses - everything.  When I'm done, I'm
filling with either Mobil or Esso because I have CONFIDENCE, based on my own
RESEARCH, that it will perform, won't damage my system, and I will be able
to flush and fill my hydraulic system regularly without mortgaging my house.

Stephane