Re: motor oil , which one??

[Matthew Yip <mgyip@yahoo.com>]

At the risk of starting an Oil thread (shoot me if it happens), over the past
15 years or so, GM and most of the domestic manufacturers have engineered
their engine bearings to run best on 5W-30.  This was most likely done to eek
out a tiny bit more efficiency from their inefficient designs without having
to incur the costs of retooling their engine manufacturing plants.  My '90 GMC
required 5W-30 which I used dilligently for all 101K miles I owned it - true
to GM form, I traded it with a slipping trans and a valve tick that could be
heard for miles.  

I don't recall the oil specs for new VWs but my '86 called for anything from
10W-30 to 20W-50.  While I've raced on 5W-30, I've also been berated by a VW
Technical trainer that the oil is too thin for VW bearings.  Considering what
the bearings looked like after 5 races, I'd agree.  Oil suggestions should
still remain within the specs spelled out by the owners' manual.  


--- Jason Kendall <jasonk@widomaker.com> wrote:
> You're using 10w-40 for the break in?????  My father is an engineer for GM
> in their power train plant.  When I rebuilt the motor on my old 8v Scirocco,
> he (my father), as well as the other engineers agreed that 5w-30 had to be
> used.  They all said that 10w-40 was waaayyyyy too thick.  And they scolded
> me when I told them that I run 20w-50 in it too.  They said that 20w-50 was
> like putting molasses into the engine, it robs horse power and causes excess
> heat.  
> Now these aren't my thoughts, just what I was told.  And I know that they
> build low revving American engines, but still, these are the guys that are
> building motors, period..... so I figure that their advice is pretty
> credible.
> Just take this advice for what it is, I'm not trying to start
> battles.....everyone has there own opinions.  Just passing along info.
> 
===
Matthew Yip
mgyip@yahoo.com

'87 GTi 16v :)
'88 M5
'99 F350
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