[T3] Stupid question #395 Oil change time?

William Jahn willjahn975 at gmail.com
Tue May 28 11:29:15 PDT 2019

The W stands for winter and 30w-30 not sure.
Jim I only use 20W50 because 40 single grade is no longer available here. I
figure on start up say 70 degrees since it's multi grade it's not 50 weight
until it gets hot. I thought I'd try the Valvoline 20W50 racing oil just to
have the zinc , Valvoline also has a 20W50 none racing oil that has 830 ppm
zinc and the racing has 1400 ppm as far as I can tell castrol has no zinc
at all. The racing has less detergent yet since I only drive 250 miles per
year and changed it every year I'd be good. It does get hot here. I also
thought I might use 2 qt's of the racing oil and 1/2 qt of the other just
to get more detergent yet this may not be needed.


On Tue, May 28, 2019 at 10:45 AM Jim Adney <jadney at vwtype3.org> wrote:

> I think there are a few basic rules we can apply to oil changes.
> 1) Change it every 3000 miles, or at least once a year.
>         a) Short trips are harder on an engine, but short means too short
> for the
>         engine to fully warm up.
>         b) Warmup happens faster in warmer weather. 50 F may seem cool to
>         you, but that's nothing compared to -20 F.
>         c) If you don't have the complete thermostat, linkage, and flaps,
>         installed, you should assume that your engine NEVER warms up.
> 2) If this car is going into storage for an extended time, change the oil
> first,
> so the engine sits with fresh oil, not contaminated oil.
> 3) Zinc, in the form of ZDDP, used to be an essential part of any engine
> oil,
> but it poisons catylitic converters, so it's been dropped. Cars with Cat
> Cons
> switched to non-ZDDP oils and roller cams, so now there are few standard
> oils that are good for flat tappet engines. I THINK that any oil out there
> that
> has the API seal on the front lacks ZDDP. You might find diesel oils that
> lack
> this seal. (This API seal has a zig-zag border and is always found on the
> front of the container, not to be confused with the smooth round Service
> Rating on the back.)
>         a) ZDDP is especially important during breakin of the cam. It may
> not
>         matter so much in a well broken-in engine.
>         b) It sounds like GM's EOS is a good source for ZDDP.
>         c) I'd be surprised if STP had ZDDP in it, as that would make it a
> very
>         bad choice for any modern engines. I'll check on that later this
> week at
>         my FLAPS.
> 4) Going to higher viscosity oils, like 20W-50 may seem like a good
> choice,
> but that can be misleading. It takes more engine power to pump a high
> viscosity oil and it may take longer for the higher viscosity oil to reach
> critical
> places in the engine upon startup. High viscosity oil is a poor choice for
> engines that spend a lot of time in warmup. This is not as simple a
> problem
> as it might seem.
> I used 20W-50 only one time, when I had an oil leak. That slowed the leak
> until I had a chance to fix it. My favorite oil would be 20W-40, but I
> haven't
> seen that available for decades. I'm now using 15W-40 diesel oil that
> lacks
> the API seal.
> I've never fogged my engines. In fact, I had to google it to find out what
> this
> meant. Seems like it's especially popular in the 2-cycle world, but it
> makes
> some sense. Anyone else out there do it?
> Quiz Question #1, for extra points: What does the W in 20W-50 stand for?
> Quiz Question #2, for extra points: would 30W-30 have constant viscosity?
> --
> *******************************
> Jim Adney, jadney at vwtype3.org
> Madison, Wisconsin, USA
> *******************************
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