Mobil 1 oil weight

[Ameer Antar]

I did some reading and it looks like Mobil 1 and Penzoil both are GF4 rated
(and PAO-based). I've had trouble finding anything with GF5. Unfortunately,
none of the manufacturers give the rating on 40 or 50 weight oils, so they're
probably not GF4. I've had no trouble with 10w30: no clatter, no leaks, but
then this is a rebuilt engine. I think I might stick with it since the 40
weight is not as highly rated. 
 
I just took another look at the oil grade chart on SJM's site and noticed that
the chart for the '95 S6 looks very similar to the chart for the 5kt/tq. What's
interesting is that the '95 shows a second group for "Energy Conserving Oil".
Here they say it's ok to run just about anything all year round: 5w30 - 10w40.
I think this shows that oil has changed quite a bit over the years. I think
almost all of the oils are Energy Conserving except for the heavier weights, so
with that and the fact that it's fully synthetic, I think 10w30 is probably
fine for the summer. I might switch to 5w30 or even 0w-30 during the winter. I
think the main thing is that the second number, which reflects the viscosity at
temp is correct. The first number just says how easy it is to flow at startup,
which is definitely important for winters here in the NE. 
 
So I think the lesson learned is: 10w30 for warm weather and 5w30 for cold as
long as the oil is EC rated. But if you have noisy lifters or weak seals,
thicker oils will help.
 
-Ameer 
 

-------------------- Original Message --------------------
From: Taka Mizutani [t44tqtro at gmail.com]
To: Steve Marinello [smarinello at entouch.net]
Cc: Ameer Antar [antar at comcast.net], Quattro List [quattro at audifans.com]
Date: 4/30/07 7:47:51 AM
Subject: Re: Mobil 1 oil weight

 Same experience here- Mobil 1 15W50 (before they went to the crap Type III
that they're using now) never burned any oil, no lifter clatter, good oil
pressure and oil temps. Even subjected to summertime track abuse, the oil
didn't crap out on me.

I won't use the light stuff in the I-5 cars- I tried Castrol 5W50 in the 200,
LOUD lifter clatter, oil consumption, etc.

Mobil 1 10W30 in the winter months was okay, but I used oil, maybe 1/2 qt.
every 5k oil change.

I'm currently running Pennzoil Platinum 10W30 (the old Group V stuff) or German
Castrol Syntec 10W30 or my last existing bit of the old Mobil 1 10W30.

I've put Quaker State Q Power full synth in the Miata, because it's normally
aspirated, not high strung and I don't really care- engines are dirt cheap for
a Miata. Still run full synthetic and do 3-5k oil changes even in the engine
that I don't care about.

Taka