yearly oil change or not !!!

[fmracer]

I have been searching for a definitive scientific answer to the question of changing oil at a specified mileage or time whichever comes first. In other words does oil degrade in the engine over time, with low mileage? Facts please if available.

 

[labman]

I hope the auto manufacturers are basing their 3000 miles or 3 months severe duty schedules on facts and not marketing hype. Even longer schedules usually include both miles and months, which ever comes first. I think the number of miles is less important then the length of the trips. The little old lady that only drove the car to church on Sunday might be able to go a long time on an oil change if the church was 30 miles away, plenty of time to boil out the water and acids. On the other hand, spread those 60 miles out over several trips a day all week, and maybe the 3 months makes sense.

I do know when I was doing 6 month changes on my 81 Phoenix, the short trips left so much sludge under the valve covers, the oil could hardly get back down to the crankcase. SM might do better than the SF did back then.

 

[cham55]

I am interested in this as well because I have a truck that gets driven very little. The last oil change it had was on 11/11/2004, 8 months and 20 days ago. But only 700 miles were put on it in that time.
Usual trip is 6 miles to and 6 miles back (55mph). Occasionally a 60 to and 60 back trip.(70mph). Obviously it isn't driven everyday.

1993 Dodge D-150 pickup V8 318cc
83,763 ORIGINAL miles (I know because I bought new)
Pennzoil 10W30 and the evil FRAM oil filter
climate: outside Nashville, TN
no dirt roads, no towing

This is the longest it has gone without an oil change, normally did it every 6 months. Thinking about switching to Valvoline Maxlife 10W30 and the Valvoline Maxlife oil filter since I got it FAR.

Also wondering how often it should be driven. I know it is not good for them to sit around but I can't find anything about how often I should drive it.

 

[cham55]

add email notification, oops

 

[martyi]

Cham55, this is a question I have as well since my new Honda Ridgeline truck gets used very little. I do try to take it out on the road for a 70 mile or so trip to the "city" but for the most part, I go a couple miles to the gym or four miles to the hardware store and thats it.

I have heard that short trips are worse than almost anything on oil and your engine and once a week trips should be taken so the oil heats up to temp for a while. I have an oil life monitor on my Honda that tracks temps, short/long trips, engine revolutions, etc. I think the best thing for me to do is rely on it. In your case, probably more frequent oil changes are in order or, just go to synthetic and change every 5000 miles, regardless of time.

 

[haley10]

I think oil life monitors, like the GM OLM can take some of the guess work out of this and add some science to it, in vehicles so equipped. It seems to not penalize very much with time as long as the vehicle is not used. Short trips rack up the penalties quickly.

The more expensive extended drain synthetics (such as Amsoil) still put a 1yr. time limitation on useage. The general consensus seems to be that 1yr. should not be exceeded even with HDEO or syn.