Oil Change Intervals If Low Milage


I have a '00 Ford Explorer, and more recently have been driving only 3-4000 miles a year (normal town/fwy driving). Would it be safe to do oil changes just once a year (have been on 6mo. schedule)? I was told that oil breaks down just sitting there, but the guy that told me this may have wanted to sell me more oil.


yes oil does break down. Switch to synthetic oil and you’ll be fine for a year without changing it.


No, oil doesn’t break down just sitting there. Motor oil is quite inert. Yes, the guy wants to sell you more oil. Your notion of once-a-year-changes seems quite satisfactory to me, regardless of whether you use crude or synthetic.


I agree with Mike, oil will break down…if it just sits around for a million years. He must be a synthetic oil salesman, Huh? In my opinion and with the experience that I have with government fleet vehicles I would say that you are pretty safe only changing your oil once a year IF you only drive 3-4000 miles a year. Government agencies only change the oil in large vehicles after an analysis is done on the oil - sometimes semiannually. I have a 93 Explorer with 225,000 miles and I have only changed the oil when it looks dirtier the normal. Need I say more? Just make sure you regularly check the oil level.


I suggest that you start the vehicle up once a month until the engine reaches full operating temperature. I would also take it for a short ride just to “exercise” the brakes and getting all other lubricants circulated in the differentials, wheel bearings and transmission. That’ll also get the oil well circulated and get any residual moisture out of the engine and transmission. Check the tire pressure before you go for your short ride. Now you really don’t have to take it for a ride every month, but warming it up and running an automatic trans. ‘through the gears’ while just sitting there will give you peace of mind that the tranny isn’t screwed up. If you want to extend the ride out to three months, that’d work, too. Think about your fuel, also. Today’s fuels, generally, will stay ‘good’ for 6 months–maybe more. Your monthly or quarterly rides will tend to have you pump in 8 gallons or so of fuel and keep your fuel fresh. Or you can pop in a bottle of "Stabil"or other fuel stabilizer and put new fuel in after 11 months or so. But you have to use up that older fuel every once in a while and replace with fresh fuel.
Oil: If you do the above-suggested stuff, I would change the oil and filter at the half-way point on the Manufacturer’s suggested intervals. That’s between the ‘severe’ and ‘normal’ operation schedules. By the way, starting 'er up every month will also keep your fuel lines and injector system full of fuel instead of just evaporating off or otherwise drying out.


If the oil was sitting in a car with a constant temperature of 70 degrees then I’d agree. The only way this can happen is if the car is kept in a heated garage. The constant change of temperature and moisture are all factors that will break down the oil. It will take a LOT longer…6 months in my opinion is long enough to have an adverse effect on the oil.


I have a 93 Explorer with 225,000 miles and I have only changed the oil when it looks dirtier the normal. Need I say more?

Yes, you do. It’s been said on here time and again…you can’t judge the condition of oil based on its appearance. To truly know how much oil life is left, you’d have to send it to a lab for analysis. It’s more cost-effective to change the oil twice a year than to send samples to a lab or replace your vehicle after you accidentally destroy the engine from neglect.

To the OP, changing your oil once a year with synthetic oil will probably cost you only slightly less than changing it twice a year with the conventional oil you’re likely still using. The choice is yours, but I’d stick to your current schedule just to be safe.


It depends on some other factors. Do you put on this mileage in cold weather? Do you put on this mileage driving the vehicle every day, or 100 miles at a time. If it is mostly short trips and includes cold weather, you never get the oil warmed up enough to boil off moisture and other volatile chemicals so you need to change it frequently.


Change it twice a year . . . spend the extra $20 . . . and forget about it. It may be correct that oil in the bottle on the shelf at the parts store lasts a long time. But oil, in the crankcase . . . exposed to the contaminants and such in your engine, make this a no-brainer. Rocketman


Your owners manual will give both a mileage and time interval for oil changes. Go with what it says. Low mileage can wreak havoc on an engine if it is cuased by many short trips.


You have a similar driving pattern to my 90 year old mother-in-law, who drive 4-500 miles /year. Her Pontiac Sunbird has 2 oil changes per year, spring and fall, using regular mineral (dino) oil, and her garage does all the seasonal checks for free.

She believes, and I agree, that for her this is a $60 per year win/win situation.


I would be tempted to go to once a year with synthetic oil if you are diving only 4000 miles per year. If you are concerned about the condition of the oil, try waiting a year then sent out a sample for analysis. The analysis costs about $20 and will give you very good idea of it’s condition.


Oil does not break down “just sitting there”. To extend your oil life, do not go for short drives as was mentioned. Drive for at least 10 miles without stopping before parking the vehicle. Your oil will be good for yearly changes according to the computer furnished with our last two GM cars. A while back, Mercedes determined that regular oil, not synthetic, is good for 18,000 miles if driven without stopping.


That’s the magic word; WITHOUT STOPPING. A warmed up engine going at legal highway speed puts out very little pollution that ends up in the crankcase. The oil additives are hardly depleted, and no raw gas or condensate ends up in the oil. Long haul truckers go 25-30,000 miles or more quite easily before oil changes. On the other hand, our local city busses need their oil changed every 8000 miles, since this is all stop & go and idling!

Most of this typoe of info is in your owners’s manual.


The last time I changed the oil on my 79 chev.short stepside, a whole 1000 miles had elapsed …and TWO years ! but no worries mate.