Low Mile Extended OCI

[FloatingBrick]

I've been doing one year OCIs on my wife's 01 Grand Marquis (4.6) and my 00 Taurus (3.0 OHV) DD.

She puts ~7000/year with mostly back roads and highway miles. I've been running Mobil 5000 5W30 with a PureOne filter.

On my Taurus, I put ~2600/year with light traffic city driving. It's 10 miles round trip to work M-F with the occasional errand during the week and on the weekends - so the oil does get nice and hot a few times a month. I've been running Pennzoil Platinum 5w30 the last three oil changes.

Here is my question. I still have some PP left and 18 quarts of Mobil 1. If I use a Mobil 1 or K/N filter, what are your opinions on going 2 years and 6k miles with the synthetic? It just seems like a waste to me to change it out with less than 3k miles on the good oil.

I suppose I could use up the synthetic in my wife's GM, but she puts easy miles on and the Mobil 5000 seems to be doing fine.

TIA for thoughts and flames

 

[synthetic_crazy]

I would be most concerned about fuel dilution and moisture content in the oil.

If you want to go 2 years on the synthetic, I would pull a sample at the 1 year mark and see how the oil looks. If all is well and the TBN and TAN are in an acceptable range, then proceed to the 2 year mark.

I like to err on the side of caution, so I would use a conventional (like Pennzoil conventional)in both cars and change every 6 months. Oil is cheap insurance against internal engine corrosion.

 

[HTSS_TR]

If you do 15-20 miles or longer few times a month on Taurus I don't see any problem with 2 years OCI at around 6-7k miles.

Another option is switch car, your wife drives Taurus 1-2 weeks a month.

 

[JHZR2]

People are alwqays concerned about fuel, but dont have evidence to back it up. My mother has driven her 97 plymouth on 5 block commutes, 6x/day, since she bought the car new. It is still doing them perfectly.

We found via used oil analysis that M1 at the non-severe interval was fine. The car now has 150k+ on it.

 

[MarkStock]

I think 7k on conventional over a year is too much

If you are not doing a used oil analysis then Synthetic on the GM would be advisable for 1 year and 7k

Or you can get your wife to drive your car so that each car gets 5k a year and so your Taurus gets more highway time

Many will say that in your circumstances a synthetic could do 7.5 to 10k somewhat regardless of time so long as the oil gets hot often enough

I have an 04 Taurus dohc and do 5k 1 year. Without a used oil analysis I don't want to take the chance to save a little money

Lastly use a pea cleaner in the taurus

 

[FloatingBrick]

I have suggested switching cars with my wife occasionally, but she does not seem thrilled with the idea. She likes the ride and feel of her GM. She also uses the accelerator pedal as an on/off switch and likes the get-up-and-go of the 4.6.

Since I am coming up on the one year mark, I'll pull a sample and send it off to Blackstone. If it won't go 2 years, I'll start running the conventional in the Taurus for 5k and the synthetic in the GM for the 7k.

I may go to that routine anyway. I like changing oil and two years is a long time to wait.

Thanks for all of your thoughts.