I've owned the truck since new and have always changed the oil every 5K miles. Since last December I have been semi-retired and working part time from home not putting near the miles on it I used to. I have just now put 5K miles on it since last December. My question is should I change the oil every 6 months even though I've not put 5K miles on it?

I looked in my manual and if it's there did not find it.

 

I thought the generally acceptable time limit on sitting oil was 12months.. I may be wrong though..

 

Right or wrong, I change mine once a year, and it's usually about 5K miles.

 

It should be OK. I change every 6 months which is about 5,000 miles, but I am modded.

 

Personally I go by mileage and not age. If you are using high dollar oil you could always have an oil analysis done.

 

Based on UOA, I can run regular dino oil (Valvoline) for about 15K miles. I don't tow very much, and when I do it's a pretty light load.

Over the winter, oil tends to collect some moisture and the pH starts to drop. Regardless of miles, it should be changed every spring. Even in Del Rio, TX.

BTW, I was stationed down there many years ago. Back when Ma Crosby's was the place to go.

 

Thanks for the replies guys, and boB, thanks for your service. Don't know if Ma Crosby's is still around or not as we do not go to Acuna these days.

We relocated here last December to be closer to our daughter, son-in-law and grandkids. So far so good, I must say the people of Del Rio are the most friendliest I've found.

 

I go by mileage also. I will however admit to being jealous of you and your problem. I normally figure 650 miles per week.

 

Hah, yep, it has been quite the change from ~24K miles per year to this. Sure helps with the diesel bill!

 

for what it's worth I change my oil every 10k miles... which ends up being about every 8 months.

 

The 6 month interval in temperate climates, regardless of miles because of condensation and the drop in PH. Although the air filter is not part of this thread, an fresh air filter is very important in fuel consumption. Unfortunately, I purchased 6 new filters at a discount price and have discovered that they are overly restrictive. These filters were made in China and they cost me 1 mpg when in use. Not all good deals are good deals. The vacuum detector on the air box is absolutely worth monitoring. On the other hand, I will never use a K&N, as they do not filter very well and plug up very fast. I change air filters also on 6 month intervals and use December and July for timing because of spring pollen.

 

The condensation issue is easily overcome by simply starting the truck regularly and bringing it up to operating temperature. This burns off the moisture. Easier to do then changing oil.

 

I go by mileage and not so much by age. 8-10k miles.

 

5k miles is my preferred interval (used oil analysis showed I could go much longer) and it works out to about once a year for me. Even if it didn't I would probably change once a year anyway.

 

I believe most folks, knowledgeable in diesel, will tell it’s prudent not to go longer than 6-months – regardless if recommended mileage hasn’t occurred. This is not only due to moisture that will occur, but combustion creates toxics that will break your oil down – even without running the recommended mileage. Consequently, your engine wetted parts will see reduced lubrication from the contaminated oil. You can usually boil out the moisture by running the truck “at temperature” for an hour or so – but the oil will still see chemical breakdown. As others here have touched on; OA will provide exact info to make your decision. Also, running a “true” full synthetic (Red-Line or Royal Purple) will help some in combating the toxic side effects of combustion, but even these oils will break down.