3 months oil change?

Depends. A daily two mile trip is harder on the engine that a weekly 50 mile trip. So is very cold versus nice warm weather.

If your trips warm the engine well and are infrequent, I'd stretch a bit but if they are short and in cold weather. I'd stick to three months. Miles makes a difference, but if the oil get contaminants that are not burned off, just sitting can have an adverse affect. One of my cars sits for a week or three between uses. I go 6 to 12 months for changes on that one.

Generally if one drives less than the recommend mileage, at which an oil change is recommended, that indicates a lot of short run use which is harder on an engine. By changing oil on a timely bases, rather than mileage, there is less of a change that the oil will become contaminated with the byproducts of combustion.

Having said that, I'm curious as to why a 2005 manual would suggest 3,000/3 months. GM and others generally recommend 5,000/6 months WOF. The latter change interval is more than adequate to prevent problems in the engine

mike hunt

When you have a new car, - or even an older one that you intend to keep - a 3 month/3000 mile change interval is not a hell of a lot of money.

In the fleet service business, in the eighties, we did oil analyzing on hundreds of fleet vehicles to determining the optimum oil change intervals, since there is so much of variation on annual milage accumulation on fleet vehicles. Some are driven thousands of mile every month while other only hundreds. We discovered, even with the wide variation of mileages, that at 5,000 oil quality was more than sufficient to do its job. We never went longer than six month between changes however. I own a 4cy domestic car, that I purchased new in 1970, that currently has nearly 300K on the clock. The oil was changed every 5,000 miles

The odds are around 95 to 1 that one will not keep a vehicle, purchased new, until it dies. Statically in the US the greatest majority of vehicle purchased new are traded, in three or four years with 45K to 60K on the clock, on another new vehicle. The majority of those that are not traded in three or four years are traded in seven to nine years, with 110K to 150K on the clock. The average used vehicle is traded in one to three years. ;)

mike hunt