oil change question

[fourtrack78]

Well now that the wife drives the car, its not racking up the km's. My last oil change was in Dec 08 and next change is for march09. My question is, we have only put about 2500 km on it since the last oil change, the oil still looks good and @ the right level. Should i just do the oil change or wait for another 2500 km. My oil changes are done at the dealer.

[kevcol74]

Although your oil "looks good", over time it develops acids in it. So letting the oil sit too long, even though not at the mileage, can damage the engine. Thats why there is a "kms or date" on your sticker.

[Hives]

Although your oil "looks good", over time it develops acids in it. So letting the oil sit too long, even though not at the mileage, can damage the engine. Thats why there is a "kms or date" on your sticker.

Never new that. How much time would say it would take for the acid to develop? Two months after the date ur supposed to change it?

[kevcol74]

Never new that. How much time would say it would take for the acid to develop? Two months after the date ur supposed to change it?

The acid develops as you drive, so its already there. There are more knwledgeable "oil gurus" out here that can explain it better I'm sure, but there is a date put on there for a reason. A friend has a 1987 Grand National with 35,000kms on it, they change the oil every 3 months, regardless of it moving or not. (He then reuses the oil in his regular driver or tractors...lolnot highly reccomended!)
Its like when I bring my Escape in for an oil change, they show me the dipstick and ask me "are you sure you are due?" Then I show them the mileage, and they understand. Just because it looks good, doesn't mean it is good.

[5_Alive]

Its because moisture collects in the engine between the valves and seals and causes corrosion and build up.
Make sure you have it changed often enough just to be safe, as in, every 3-4 months, maximum. As long as the car gets some driving, but its not good if they are short trips on the same oil, moisture works in funny ways.
So yes, Kev has a solid point.

[Jeff0]

Some dealership have date and mileage on their maintenance sticker and some doesn't have they only rely on mileage...In my part I changed either 5 1/2 months or 6.5K - 7K. Motor oil now a days can with stand in longer period of time as not like before, that's why some newer car has oil computer and it rely on the mileage...

[slam525i]

I agree with the short-trips thing. As a pilot, I was always taught that short runs where the engine doesn't get hot enough to boil off the water is bad, but I don't see how moisture can occur on the valves and seals. Can someone enlighten me?

[Fobio]

you guys are all right...moisture collected from the actual combustion process is generally burned off after longer trips where the engine gets completely warmed up...short trips does not allow the engine to do so and thus increases moisture buildup. this water essentially reacts with oil...overtime, the oil breaks down.

you should change your oil every 3 months even if you don't drive the car.

[Krisekca]

1st what oil ?
Moisture and Fuel will go away on longer trip ....
Good Oils have good corrosion inhibitors so thats not a problem...
Acid yes ....

1 year oil change is not a problem on good oil ...

[Harbour Rat]

1st what oil ?
Moisture and Fuel will go away on longer trip ....
Good Oils have good corrosion inhibitors so thats not a problem...
Acid yes ....

1 year oil change is not a problem on good oil ...

Oils formulated for diesel engines have higher Total Base Number, or alkaline content to fight acid build-up over the long drain intervals more common with diesel engines. There are CJ4/SM rated oils available in 0W30, 0W40 and 5W40 which would be suitable for our engines.