# Hours of operation - equivalence to miles / time

Status
Not open for further replies.

#### aa1986

If I have a manufacturer oci of 10,000 miles / 1 year, how many hours of operation do you think that is equivalent to?

250 @ 40mph. Not a matter of thinking, but knowing.

Last edited:

#### aa1986

So if I averaged 1mph I could do 10,000 hours? I didn't mean "equivalent" literally!

#### OneEyeJack

There are lots of formulas. You can probably figure out a few for yourself. Some use gallons of fuel used based on the idea that if you're using a lot of fuel you're doing a lot of work or a lot of idling. Either way the oil is still working away.

#### volk06

125hrs was about 5700-6500 miles for me according to my instrument cluster. Mix of highway and town driving

#### raytseng

calculate out the MPG and use fuel consumed.

#### Wolf359

Originally Posted By: raytseng
calculate out the MPG and use fuel consumed.
Did you actually do this? MPG tells you nothing about how long it takes to consume those gallons. You need average speed in order to determine how many hours it translates into. On my car, the trip computer usually says anywhere from 20-30mph as the average speed on a mix of city and highway. It's even worse when it's just mostly city mileage.

#### BISCUT

My driving style in the F150 (which is largely back road and highway; 40-50mph hilly roads; 80mph highway) has me about 3k miles per 90 hours of operation. This is based off my numbers for the last 2 OCI's which were 93hrs for 3100 miles....I rounded the final answer.

#### RhondaHonda

My average speed for a ~7500 mile OCI is usually 25-30 mph. I'm usually at 250-290 hours on the oil. GM OLM will show 14-25% life remaining.

#### Quattro Pete

Originally Posted By: Wolf359
Originally Posted By: raytseng
calculate out the MPG and use fuel consumed.
Did you actually do this? MPG tells you nothing about how long it takes to consume those gallons.
I think using fuel burned has its advantages because it already takes into account things like short tripping, cold weather operation, extended idling, high speed/spirited driving, leisurely driving, etc. The tough part is figuring out what that amount should be per OCI if all you were given is a standard 10K mile figure from the manufacturer. You could be conservative, and assume that this 10K mile OCI applies under ideal driving conditions, for example with mostly hwy driving. Now, say your vehicle gets 33 mpg in such driving, then your amount of fuel burned would be 300 gallons (10,000 / 33). Now, if during your next OCI your mpg dropped to 25 because you did less hwy driving and more city driving or idling, then you should drop your OCI to 7,500 miles (300 gallons x 25 mpg). OP, if you're interested in some alternative OCI calculations that take into account a number of parameters (including fuel economy), check out this spreadsheet: https://docs.google.com/spreadsheet/ccc?...p=sharing#gid=0

#### RF Overlord

Didn't I read (here, perhaps?) that Ford calculates 1 hour of idling equals 33 miles of operation? So in reverse for the OP, 10,000 miles would be 303 hours...

#### Quattro Pete

Originally Posted By: aa1986
So if I averaged 1mph I could do 10,000 hours? I didn't mean "equivalent" literally!
No, but the 250 hours that simple_gifts calculated for you could be your baseline. Now if you only averaged 1 mph, that would sound like a very severe service to me, and you should change your oil after 250 miles (250 hours x 1 mph). Not saying that's what you should go by. It's just another way of looking at things.

#### userfriendly

When my daughter returned from the Alberta oil patch one Christmas the average speed since the previous oil change was 18 mph. When she was driving, her and everyone else average speed is as fast as possible, 150 km not uncommon. Why so many hours on the engine? Free fuel and your own space to sleep. I performed 2 oil changes in 600 miles before the Christmas break was over.

#### DrDave

I think you should factor in the load on the engine as well. Automotive engines spend very little time at rated horsepower. They usually cruise around making low power. I don't know of any formula to rely upon. Dave

#### Timbuctoo

Thats what I woulda thought until I read this: Fuel % - This is the amount of raw fuel content in your oil sample given as a percentage of total volume. Fuel dilution is common from cold starts with lots of idling (engine ECUs typically run rich on a cold idle) and short trips. This causes raw fuel to work past the piston rings and into your crankcase, which dilutes your oil and acts as a solvent, partially washing away the critical oil film and increasing wear between parts. This is why used motor oil (especially on older carbureted vehicles) sometimes smells like gasoline.

Last edited:

#### Clevy

I read an article somewhere last year that had 300 hours as a baseline but I'm not sure how they achieved that number. I have a readout for gallons burned on the C3 with miles travelled and average speed too. It's got either personal or business on the trip meter. So I use one for total hours,miles and gallons burned for the oci and the other I use to track per tank

Status
Not open for further replies.