I only drive under 7k a year and am using Mobil 1. I am coming up to the time (month) that a change is due but I am well under the mileage. Is it worth getting the oil changed anyway or should I leave it another 6 months?

 

Leave it !!!!!!

 

What about it degrading due to age though?

 

I would say leave it... unless you let it sit for long periods of time.. I only change mine about once a year and I do about 7k miles as well

 

I'm assuming you have the M1 Xw-20 oil in it. It's not doing you any favors but it does not need to come out. You'll have a lot of corrosion using a synthetic in an engine that sits a lot. Next time you change it, I'd suggest a simple blend. I assume you know that M1 in 5w-30 only has been failing IVA testing for a couple of years now. Mobil has remained silent on the failure. IVA testing deals with cam lobe wear. M1 in 5w-30 has repeatedly shown 2-3 times acceptable wear.
http://www.swri.org/4org/d08/GasTests/iva.pdf

I have a garage queen that doesn't get to see much road. It's an 89 LSC with 32,000 one owner miles on it. The last oil change was 4 years ago but I check it every year. The last report in April showed very little in the way of wear metals. TBN was still good at 7.6 which is not much less than it was in the bottle. I'm using Chevron Supreme in it 5w-30 mostly because it was the best available at time with more ZDDP and moly than most formulations. This oil change has less than 1000 miles on it in the 4 years. The car is pristine and has never seen the rain since new.

 

I'm running Amsoil in my Mach I this year and come next spring I'll dump in the recycle barrel and put in new.. I only put at the very most 5,000 miles some years much less but I hope to drive it more this year. I'd jettison that old oil..

 

Its driven 5 days a week & sometimes at weekends. Would it be better to run it Royal Purple?

 

LN, My wife has a new '11 Camry and it came factory filled and recommended with full synthetic oil. Yea, I know, but it's made in the USA, and I drive F-150's (and have for most of the last 35 years) and she used to drive Fords. (semi-long story) I know you aren't a flaming fan of full synthetic but why did they go to FS in this and not even in the V-6? What are the downsides to FS when the car isn't driven a lot of miles, but is driven EVERY day and is always warmed up when driven, just no long trips. We have free oil changes (synthetic) for the 1st 2 years and is there any good reason not to use semi- when I have to start doing my own oil changes?
I have, as most do on this forum, huge respect and appreciation for you technical input.

 

Labnerd said it well.

Oil doesn't know the passage of time in normal conditions. With UOAs, I've gradually been working my '05 F150HD and my farm equipment to miles/hours only... no time duration. For the F150 that works out to 18 months to two years. I have one farm tractor that runs out to three years and another to about two. The car is about 18 months. Great UOAs. Some caveats to that, meaning not having horrible storage conditions (conducive to condensation) and decent operating conditions (i.e. not much short hopping).

Labnerd: Is the syn vs mineral corrosion thing such a big deal? My understanding is that syn doesn't react well to moisture, which can be an issue in storage, but the situation doesn' become a problem often. Anyway, would like to know more if you have it.

 

Code58, the reason Toyota went to the "full" syntheitc is due to their changing of the oil change interval. If you look at the owners manual it calls for changes every 10,000 miles. Nothing changed in the engines and the 2010 models used any Xw-20 oils so when the time comes for you to do the changes, use any quality oil and change every 5000-7000 miles. You might consider running the oil to 5000 and pull a mid-stream sample and have it tested. Depending on the fuel dilution and TBN will pretty much tell you when to change. Hope you have better luck than most with that Camry. They have been plagued with tranny issues.

Jim. As we both know you want to get the most for the least. The higher costs of the synthetics buys you more issues than a blend with engines that sit. That's why fleets almost always use spectroscopy as a maintenance tool. The synthetics do not have the ability to protect an engine from corrosion like a blend or dino oil. No, the engine isn't going to fail any quicker using a synthetic but why spend the bucks when a lower cost blend does a better job. The blend will also have much better startup properties than a synthetic for engines that sit. Synthetics do not naturally adhere to the parts like a blend or dino oil. That's why most will use a copolymer tackifier in the formulation. But it too can run off of parts if left long enough. FWIW, a report on an engine that sits regardless of miles will show more iron in the flashing. It's not necessarily wear but corrosion that's showing up. Your tractors probably track/trend towards the high side from them sitting versus a season of running hard and then getting the report.