Oil change intervals for a rarely-driven vehicle

[Mike242GT]

Here's another reminder for you all to change oil in your infrequently driven vehicles according to time and not mileage:

Vehicle: 1985 Volvo 245 DL
Oil: Mobil-1 Tri Syn 10W-30
Miles on Vehicle: 217,747
Miles on Oil: 2,150
Time on Oil: 18 months

Al: 1
Cr: 0
Fe: 4
Cu: 8
Pb: 138
Sb: 0
Mo: 4
Ni: 0
Mn: 0
Ag: 0
Ti: 0
K: 0
B: 0
Si: 27
Na: 3
Ca: 1,945
Mg: 32
P: 342
Zn: 815
Ba: 0
SUS Visc: 55.7
Flashpoint: 375
Fuel: Antifreeze: 0
Water: 0
Insolubles 0.6

This vehicle is a candidate for an Auto-RX treatment, which is probably what I'll do next. It's getting driven a bit more now than it was, and I'll follow up the Auto-RX with a shorter interval and another UOA to see where things are.

I've already read here and heard elsewhere that a thinner synthetic like Mobil-1 is probably not the best choice for an infrequently driven vehicle or a vehicle that spends time in storage, and that a 15W-40 diesel truck oil would be more appropriate. Since I'm already using Chevron Delo in another vehicle, that's probably what I'll switch this one to.

 

[Ken4]

I thought infrequent use would increase the Iron content. I wonder where all the lead and silicon came from?

 

[Drstressor]

High lead with low copper is strange. I always see silicon go up with infrequent use. The crankcase is not a sealed system and dust gets into everything eventually.

 

[satterfi]

If it were me, I'd retest. I'd want a little more evidence than one cheapy $20 oil analysis before I ran to the bank. Mistakes are made.

A TBN reading would be nice, especially in these conditions. I doubt a low TBN results in high Pb though. More than likely, a low TBN would give high Fe numbers.

 

[Al]

quote:

---

Originally posted by satterfi:
If it were me, I'd retest. I'd want a little more evidence than one cheapy $20 oil analysis before I ran to the bank. Mistakes are made.

A TBN reading would be nice, especially in these conditions. I doubt a low TBN results in high Pb though. More than likely, a low TBN would give high Fe numbers.

---

I totally agree. The Phosphorus is not right . I wonder about the lead. And the Iron seems too low. I have very little confidence in this analysis.