Mobil 1 5W-30 SM, 6012 miles, '94 Grand Prix 3100 v6

[WishIhadatruck]

Blackstone Report
Engine: GM 3100 V-6
Vehicle Mileage: 192,004
Oil Mileage: 6012
Make-up Oil Added: Zero
No additives in the fuel or oil used
Oil Filter: Wix
Air Filter: Wix
Driving Style: 2/3 Hwy and 1/3 City, mostly 30 mile 1 way driving to work and back. It did haul a few loads of mulch this spring in a trailer with this oil also.

Aluminum: 2
Chromium: 0
Iron: 11
Copper: 4
Lead: 21
Tin: 0
Molybdenum: 75
Nickel: 0
Manganese: 0
Silver: 0
Titanium: 0
Potassium: 2
Boron: 45
Silicon: 14
Sodium: 7
Calcium: 2241
Magnesium: 19
Phosphorus: 583
Zinc: 708
Barium: 0

SUS Viscosity @ 210 degrees: 59.9
Flashpoint: 395 degrees F
Fuel: < 0.5%
Antifreeze: 0.0%
Water: 0.0%
Insolubles: 0.3%
TNB: 2.1

Blackstone flagged the high lead but they weren't sure it was from bearing wear since the other wear materials were low. They said it could be a particle streak through the bearings, what is that?

I bought this car in '95 with 18,000 miles on it with "regular" oil changes from the previous owners per their word. There was a Valvoline sticker in the window when I bought it. I changed the oil every 3000 miles with 5W-30 Pennzoil until around 90,000 miles and swtiched to Mobil 1 5W-30. I still stuck with 3000 mile oil changes but found this site recently and decided to go 6000 miles this time and do a UOA.

 

[TooSlick]

With this many miles, a thicker oil would probably drop the lead numbers down a bit and smooth out the engine. It looks like the bearing clearances have opened up due to normal wear. I'd try the Castrol 0w-30 or even a 5w-40 synthetic like Delvac 1 in warm weather. I'd stick with the Mobil 1, 5w-30 or 0w-30 for the Michigan winters.

Overall a very good report for a high mileage engine.

TS

 

[ATS-V]

Was this the first M1 SM fill? Do you have any other UOA's on this engine?

 

[WishIhadatruck]

This was perhaps the 2nd or 3rd SM fill if I had to guess. This is my first UOA for this car. My other Grand Prix had its first UOA just recently. It also had high lead. I'm thinking of going another 6000 miles on the current fill (same oil) and maybe I'll check it again. I only plan to run the car another year or two and retire it so I don't want to spend much more money on UOA for this car. I'm guessing the rust will encourage me to stop driving the car before the engine quits.

 

[Al]

Wow not bad. Looks like this engine has not had its intake manifold gasket changed. This might be the first engine in the history of the world that has not had this dreaded condition.

How many altenators have you changed? Auto trans solenoid valves? Plug wires? Computer module? EGR? Those are the things I can think of that go bad on this thing.

One other thing the vacuum line might go under the battery and can get corroded and fail. You'll know when you lose your ventilation control and cruise control.

 

[WishIhadatruck]

Blown head gasket in Nov. of 99, Thanksgiving eve, I remember it well. Because of that the intake gasket was changed at that point of course. Eats an alternator every 4 years, I'm due again soon. Never touched the trans. except for fluid/filter changes every 30,000 miles. Changed the plug wires once around 120,000 miles. No EGR or computer issues.

It has been more reliable the last 100,000 miles than it was the first 90,000. I wish it wasn't rusting out because it has been good to me the last few years. The only other issue I've had that these cars are known for is the cylinder lock for the ignition key failed one day and almost left me stranded. After turning the key 30 times it finally started. It wouldn't do it for the dealer I had them replace it anyway and it has been fine since. It did warn me by not always turning over on the first turn of the key for about 2 years. I told myself if it took 3 tries I would get it fixed. It went from 2 to 30 all at once. That just happened a year and a half ago. I don't think I've spent a dime on repairs since other than replacing a 6 year old battery before it died on me last winter. Just fluids. For 6 years my wife drove it 8 miles one way to work and that was about all it got other than the occasional 2 mile round trip to the store and it went through 2 exhausts in that time. With the dual exhaust outlets that was expensive.

 

[Clyde65]

High iron numbers, high mileage....yeah baby....you need Valvoline Maxlife 10W-40.

 

[friendly_jacek]

Is this a manual tranny? Any chance that you lug the engine while towing?
This can surely give you bearing wear with any oil.
Either this or your car doesn't like mobil 1.

 

[WishIhadatruck]

quote:

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Originally posted by friendly_jacek:
Is this a manual tranny? Any chance that you lug the engine while towing?
This can surely give you bearing wear with any oil.
Either this or your car doesn't like mobil 1.

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It is an auto trans so I can't really lug it much. I have 1 more oil change of Mobil 1 on the shelf and I might try something different next after that. I have some GC on the shelf for my LT1 Roadmaster, so I might try that.