Mobil 1, 10,000 miles, Chevy Caprice

[V6 Diesel]

1991 Caprice, 9C1 Police package, 5.7L, total mileage at oil change was 244,600 miles, 10,000 miles on oil. No oil was added, oil level was still at full mark. Used the “brew”and FP the entire run.

Oil was tested by Analysts this run, Blackstone the previous tests.

First 87k miles were police use with 5k mile oil changes. I used Syntec 5w-50 from 1995 about 147k miles then Mobil 1 for the last 20K miles.

The silicone is high so need to find that problem. The iron came down even though this run was thru the winter compared to the last which was during the summer. If not for the silicone might have slightly better numbers overall.

Ran the oil out too long according to Analysts, the tbn 1.38 was too low according to the report. The previous 10k miles had a tbn of 2.1 with Blackstones scale.

The column on the far right is the last test

Castrol Syntec - Mobil 1 --- this run Mobil 1-
5w-50 - -- -- - 10W-30 - 10w-30
5,000 miles - -- 10,000 miles--- 10,000 miles
Alum 5 - 6 - 10
Chrom 1 - 2 - 2
Iron 23 - 43 - 33
Copper 4 - 6 - 9
Lead 4 - 11 - 13
Tin 1 - 0 - 0
Moly 49 - 57 - 54
Nickel 1 - 1 - 0
Mang 1 - 1 -
Silver 0 - 0-
Titan 0 - 0 -
Potas 4 - 1
Boron 39 - 72-
Silicon 15 - 16 - 27
Sodium 5 8
Calcium 2944 - 2565 - 2660
Magnes 16 - 30 - 33
Phosp 740 - 657 - 498
Zinc 888 - 798 - 855
Barium 0 0

Sus @210F 95.7 - 70.6 -12.9 vis cs
Flash 375 435-- ?
Insolubles 0.5 0.4--?
Fuel 0.5 -
1.38 tbn
Glycol - negative

 

[Last_Z]

I think your report is pretty good! As you stated, you need to check the intake for leaks. Also, I would move to a higher viscosity in order to provide a thicker protective film for the bearings and rings. You engine has a lot of miles and it's fairly lose by now. I think a mid to high 40W should do you good!
I would cut back to 8.5-9k mile OCI just to be safe......even then, you are getting way more than you paid for the M1 and the additives.

Rick

 

[Schmoe]

Lead looks really good for this amount of miles. I would move up in viscosity too, try a 15W-40. Si could be coming from a cracked hose or bad PCV valve.

 

[Patman]

What oil is in this engine now? 10w30 M1 again?

Lead does look better with the thicker oils in this engine over 10w30 though. The 5w50 Syntec actually did a pretty good job. Definitely better for the bearings over the thinner stuff. I think going halfway though, to a mid 40wt, would be just the ticket with this engine.

 

[V6 Diesel]

I happened to have a good supply of Schaeffers 10w-30 on hand so am running that right now. I had thoughts of running Mobil 1 15w-50 for the summer.

I did try to thicken the Mobil 1 up by adding half a bottle of EP 132.