[Vwdiesel] Risks of straight weight

[Val Christian]

> I've had the V/C off a couple of times and all I see is black oil. No sludge or any of 
> that milk shake stuff at all.
> Engine is fresh - about 60k miles. Never took actual compression test with an instrument, 
> but I can hear the load on starter as each cylinder comes up on compression. They are all even any ways.
> Blow by is minimal - no oil on air filter. I've never had to add oil between changes. 
> I change Mobil1 at 4,000 miles with Mann filter. Oil still seems to be performing like new, but
> I'm afraid of carbon build up in filter and subsequent bypass.
> My other vehicle - 81 pickup - 1.6 N/A - had broken and stuck rings when I bought it in 1986. 
> This I attributed to the P/O's use of oil not diesel rated. New head, rings & bearings in '88. 
> I use Mobil1 in this also, and plan to put 
> serious mileage on it this winter, save the Jetta from the salt as much as possible.
> I had no idea that oil lost it suspension abilities as temp dropped. Curiouser & curiouser.
> I never heard of blotter test till I came to this forum, and I don't know what is involved. 
> Care to enlighten me?
>  
> Bob in the Entire State

Bob,

The soot is fine enough so that it shouldn't clog the filter.  Bets are 
off at -30F, in my book.  You have clean metal, that's a good place to me.
It doesn't take much black soot to color a quart of oil.  For the blotter test,
put a drop of dipstick oil on a sheet of copy paper.  Wait a couple of days.

Try searching the web for paper chromatography.  Ancient technique, and 
I can't give you a reference relative to engine oil.  It's fun to do, and 
you may learn something from it.  Essentially chromatography is way to  measure
differential solubility.

Folklore has it that the railroads used this method of determining when
oil should be changed in diesel engines.  Since this method was first
documented in the 1940's, Hagar probably invented it in his spare 
time taking breaks from spying on the Germans.  Idle kids create new
solutions (no pun really intended).

During this same time period, organic eaters were analyzing their
V-8 juice with similar methods.  Yep, that was when Hagar was helping
with the V-2 program, by observing the exhaust, so they could 
hillbilly tune the injectors on the rocket engines.

Bob, stick with the Mobil 1, but if you do an engine breakin, please
use a straight weight SAE 30 oil for the first 2500 or so.

Val

ps: My guess is that high detergent oil will blot different from 
other oil.  Oh, and if you see rings of copper and lead like colors,
you will need more help than paper chromatography.  Clean out the 
garage, because the car is coming in, baby!

pps: If you're willing to spend $15 or so, you can have your oil analyzed,
and you'll probably find that your 4000 mile interval is real conservative
and might be readily doubled.