Engine Hours vs. Mileage

[Lyle's GTP]

What would be better to determine oil change intervals. Judging buy Milage you have traveled (conventional method). Or adding an hour meter and deciding what would be a common oil change interval in hours. For example 100 hours.

I don't want to know a better method or if a combination of the two would be better. I just want to know of the two, which would be more accurate.

I'm trying to settle a debate. Because I think that an hour meter would be a better way. I think this because you can normaly drive for 50 hours on the highway to reach 3000 miles. But say you are a commuter, like me. I drive about 12 miles a day, and my engine is running for about 50 minutes. So we will say, about the same over the weekend. So, in 3000 miles traveled at those speeds is about 208 engine hours. Obviously their is an inconsistancy.

So let me know what you think.

Lyle

[geoffinbc]

Hours are a much better method for sure. Especially for someone sitting in traffic.

[napatiger]

All of our tractors maintenance is based on hours.

But those will idle a higher % of the time vs a car. I am ok with 3000 miles.
Think about it...what if you had a short amount of time (miles) but you just did 1/4 mile runs, you would need to change the oil more frequently, as well as tranny fluid.

[Lyle's GTP]

I am ok with 3000 miles.
Think about it...what if you had a short amount of time (miles) but you just did 1/4 mile runs, you would need to change the oil more frequently, as well as tranny fluid.

That is a special situation though. You are not going to wait until you have don 12000 passes at the track before you do an oil change. Plus you wouldn't wait a 100 or so engine hours either.

This situation would only pertain to everyday normal engine load conditions.

Lyle

[dbtk2]

The oil life monitors in most GM cars use engine revolutions and engine temp to determine the interval IIRC.

Shawn

[Scott205]

So many factors go into how you should judge when to you change your oil. If you are in high traffic it should be changed more often, just becuase heat breaks down the motor oil. Same goes if you run the engine at constant high rpms, that will give you both heat and a larger amount of shear factor (the long chain molecule that is oil gets physically broken, make it less slick, easier to burn etc...). Finally if your car just sits there for long periods it will start to break down back into its component parts, (wax like material, distillates).

If you do use a premium synthetic you may be able to have the oil last longer but you may want to still change the filter. I am currently using Mobil 1 synthetic, and i will change the filter after 3,000 miles, add a quart of oil to make up for the loss, then change both after 6,000 miles.

[geoffinbc]

Completly agree. If you really want to get accurate on your oil changes then you should test it.

Otherwise stick to the 3000miles (5000K) and you will be safe because you are changing it before the end of the oil's life.

[Lyle's GTP]

Do you know of any test kits?

Lyle

[SHOoff]

Re: Engine Hours vs. Mileage

What would be better to determine oil change intervals. Judging buy Milage you have traveled (conventional method). Or adding an hour meter and deciding what would be a common oil change interval in hours. For example 100 hours.

I don't want to know a better method or if a combination of the two would be better. I just want to know of the two, which would be more accurate.

I'm trying to settle a debate. Because I think that an hour meter would be a better way. I think this because you can normaly drive for 50 hours on the highway to reach 3000 miles. But say you are a commuter, like me. I drive about 12 miles a day, and my engine is running for about 50 minutes. So we will say, about the same over the weekend. So, in 3000 miles traveled at those speeds is about 208 engine hours. Obviously their is an inconsistancy.

So let me know what you think.

Lyle

If you drive on the highway enough to hit 3000 miles every 50 hours on the motor, you dont need to change the oil at 3000miles. Look at the back of the bottle. It'll tell you stuff like that.

From my 97 GTP owners manual:

When to Change Engine oil
If any one of these is true for you, use the short trip/city maintenance schedule
* Most trips are less than 5 to 10 miles. This is particualrly important when outside temperatures are below freezing.
* Most trips include extensive idling (such as frequent driving in stop-and-go traffic)
* Most trips are through dusty areas
* You frequently tow a trailer or use a carrier on top of your vehicle
* The vehicle is used for delivery service, police, taxi, or other commercial platform.

Driving under these conditions causes engine oil to break down sooner. If any one of these is true for your vehicle, the you need to change your oil and filter every 3,000 miles or 3 months -- whichever occurs first.

If none of them is true, use the long trip/highway maintenance schedule. Change the oil and filter every 7,500 miles or 12 months -- whichever occurs first. Driving a vehicle with a fully warmed engine under highway conditions causes engine oil to break down slower

[Lyle's GTP]

I know all this stuff. But I'm trying to figure out if it is worth installing an hour meter to better determine oil change intervals. Especialy when doing alot of city and highway driving, under normal conditions. I think that milage is not relevant in determining any maintenance besides bearings.

Because engine run time wouldn't change on the highway or the city.

Lyle

[geoffinbc]

Very true but you are over analyzing the situation. Just change it at 3000 like you should and don't worry. Better to waste a bit of money and change it more oftern than you really need to.

[SHOoff]

I know all this stuff. But I'm trying to figure out if it is worth installing an hour meter to better determine oil change intervals. Especialy when doing alot of city and highway driving, under normal conditions. I think that milage is not relevant in determining any maintenance besides bearings.

Because engine run time wouldn't change on the highway or the city.

Lyle

It says right in that clip from the owners manual. Most of your trips have extensive idling since you're moving from light to light. It also mentions if the car is used for Police duty. Dont you a lot of times see a police car sitting somewhere.... they clock up a lot of hours on them. So just do a 3000 mile change.