I understand that the engine oil in a vehicle should be changed every 3000 miles or 3 months (just an example); but can it be changed at the mileage instead?

I drive my truck an average of 2,500 miles a year.

Seems like changing the oil every 3 months is a waste of oil.

Does the engine oil have a limited life once it's in the engine?

Just curious.

 

Just my opinion- the way I always interrpretted it, the 3 month rule was for cars that didn't get 3000 miles in 3 months and didn't get started but maybe once a month, so for my truck that doesn't get the miles in 3 months I just start it and let it reach operating temp. once a week. I change the oil about 2 times a year. I'm probably doing it wrong but don't really care.

 

Well, in your case, there are an awful lot of unknowns, but the oil itself probably doesn't breakdown, unless you run the puddin out of it, in those 200 miles a month, but depending on your drive cycle, weather conditions, oil brand & service grade, engine condition, ect, the add pack could wear out, if those 200 miles a month are short drive cyles, in humid conditions, in which the engine & oil never fully get up to their designed operating temperatures.

Moisture & combustion acid byproducts can deplete the lubes base number to a point that it can no longer deal with the acids formed & then they can begin to etch away at bearing surfaces.

The only way to know for sure whats going on in your case (& everyones case is diferent), is to pull an oil sample & have a UOA (Used Oil Analisis) done. From that analisis you could determine a safe OCI.

If you drive it each time, such that it fully warms up, the engine & it's systems are in good condition, you use good quality fuel, oil & filter, humidity is low, once a year might be ok, but again you'll not really know unless you have a UOA done!!!!

Blackstone Labs, one of our site sponsers could make a determination by running a UOA, why not check them out.

Just some thoughts to ponder.

 

I agree with PAW PAW. Also, why not be on the safe side, and simply change the oil and oil filter? For the cost of the oil change, and what you are protecting, I feel it's $$ well spent.

Ed

 

PS Blackstone Labs, is a great company. I am not saying that because they are a sponser here. They do good work, for a very fair price with their oil analysis. Friends, who have had their oil checked for the first time, have e-mailed me during the past year. ALL have complimented Blackstone for their work. Some, TRUST ME, are friends of mine, so tight they'd slam on the brakes at 55 MPH to pick a nickel up off the side of the road. Even those friends have said they felt much better about their engines, one in a rebuilt 1955 Oldsmobile V8. Blackstone Labs' report gave him a clean bill of engine health, suggestions on things to watch for, which netted nearly 7300+ trouble free miles last year in the clean '55!

Quick turn-around time as well. I would not use anyone else to perform an oil analysis.
Ed

 

I'm in the same boat, running her about 5 times/month...although, this summer, i plan on running her more, why let it rot?

I change my oil at 3k/6 mos regardless.

 

$20 with Blackstone could you a lot of money. Have a sample tested 6 months in and see what happens. I just used Blackstone for the first time and was very impressed. They send you everything you need for free right from thier website.

 

If you run fewer, longer trips (mostly minimium 15 miles) you should be able to run the oil for a year. If you run mostly short trips, then 6 months, or in extreme cases, 3 months.

 

I have a similar situation with my pickups and perform oil changes annually with no problems to report.