Time vs. Miles

[Corollaman]

I'm doing 6 month 5,000 mile oil changes on two vehicles (2016 fusion 2.0 ecoboost and 2011 Silverado 4.3 V6). Most of the time it takes longer to reach 5,000 miles especially when I change them in the fall. My question is a 7 month or longer 5,000 mile change fine? This will be Quaker State Ultimate Durability 5w30 on both vehicles. The Fusion turbo has me more concerned than the old school chevy 4.3 v6. Lot of short trips.

 

[bluestream]

Motor oil changes are usually scheduled based on the time in service or the distance that the vehicle has traveled. These are rough indications of the real factors that control when an oil change is appropriate, which include how long the oil has been run at elevated temperatures, how many heating cycles the engine has been through, and how hard the engine has worked. The vehicle distance is intended to estimate the time at high temperature, while the time in service is supposed to correlate with the number of vehicle trips and capture the number of heating cycles. Oil does not degrade significantly just sitting in a cold engine. On the other hand, if a car is driven just for very short distances, the oil is not allowed to fully heat-up, and contaminants such as water accumulates in the oil, due to lack of sufficient heat to boil off the water. Oil of this nature, just sitting in an engine, can cause problems.

 

[benjy]

which ever comes first is generally stated in many applications + oil even todays fake synthetic is pretty cheap + DIY changes are real cheap!!

 

[Cujet]

I don't believe time is a factor at all. UOA results often show TBN of quality oils at sufficiently high levels to combat acid, even after many years of low mile use.

 

[FCD]

I've run Group 1 Conventional 20w50 for more than 2 years without a problem.
As long as say +75% of times you start the car it reaches operating temperature really time isn't too much of a factor, specially if the oil has a strong TBN of say 8-10+

 

[demarpaint]

I've run 4K OCI's in my van that have taken 2 years or more. The last 5K OCI in my Rubicon took almost 19 months. I certainly wouldn't worry about taking 7 months or more to hit the mile limit you set for your OCI unless you're concerned with a warranty which states to change the oil every 6 months, or once a year for example.

 

[billt460]

Originally Posted by Cujet
I don't believe time is a factor at all.

It is if you do a lot of city driving. It's amazing when you have an hour meter and compare it to the odometer. The average speed is pathetic compared to how long the engine has run. Many people who live and drive in urban areas will always require oil changes before the required mileage.

It's why many police cars and taxi's have hour meters. They run all but constantly, but rack up very few miles in city driving, compared to the amount of time they run. Many new cars are coming with hour meters attached to the trip odometer. They will automatically calculate your average speed for every minute the engine has run. It's always much slower than you think.

 

[demarpaint]

Originally Posted by billt460
Originally Posted by Cujet
I don't believe time is a factor at all.

It is if you do a lot of city driving. It's amazing when you have an hour meter and compare it to the odometer. The average speed is pathetic compared to how long the engine has run. Many people who live and drive in urban areas will always require oil changes before the required mileage.

It's why many police cars and taxi's have hour meters. They run all but constantly, but rack up very few miles in city driving, compared to the amount of time they run. Many new cars are coming with hour meters attached to the trip odometer. They will automatically calculate your average speed for every minute the engine has run. It's always much slower than you think.

An hour meter is a real eye opener, especially if you live in a Metropolitan area like NYC. That might be the best way to determine an OCI.

 

[Gebo]

To answer your specific question, I will be in the minority but I'd go every 6 months.


On "my" really low mileage cars (less than 5000 miles/year) , I'm doing a 6 month OCI.

On "my" really short trippers and actually everything else, I'm doing 3K OCI.

Oil and filters are so cheap and I love changing my oil. You should see the auto parts guys when I come in with my 5 gal of used oil every month or so. I use a 5 gal aquarium water container for holding and transport.

 

[ka9mnx]

Either 6 months or 5k miles whichever is easier to remember. Do a short OC to get your odometer on the even numbers (example: 70,000 or 75,000) But I'm with demarpaint. I don't drive much and don't worry about the time and go by miles.

 

[cheech279]

My Accord is used in FL for four months a year, and it sits idle in the garage for the next eight months. I use Pennzoil Platinum 5w-20 and a Donaldson filter. I plan on two year intervals and don't lose any sleep over it.

 

[Dave9]

If you're hitting 5K mi. in 7 months or anywhere near that, you can't be doing all that many short trips w/o the engine warming up. I'd do yearly changes and not lose sleep if it went 18 mos.

 

[SubieRubyRoo]

In your case, why not go by OLM?

On my Fusion which did not use any oil, I did some used oil analysis and progressively kept upping the mileage until the data showed the oil was becoming used up (low TBN, viscosity started to creep up). However, I found that my car and my usage could go about 50% longer than the OLM and still have great UOA (viscosity, TBN, insolubles good) and sold the car at 134k running like new. On my Subarus I tend to go 7.5-10k depending on when the mood strikes and if they need makeup oil- I find usage will creep up a hair as the data gets into my personal "warning" zone and I use that as my indicator of when to change.

Call me weird, but I'm a guy who considers if you have to add 3.5 quarts of makeup to go 7k miles on a 4 quart sump, you are really doing about 3.6k OCIs since essentially every filter on the market will easily go 7-10k (and most much longer). If I have to add a quart for usage, it's time for me to be changing the oil and filter.

 

[FastLane]

When in doubt, change the oil. Oil is cheap.

 

[bluestream]

Oil doesn't go bad sitting in CC. unless you do a lot of stop and go driving you need to only look at miles/hours not time. My BMW is on 4 year OCI. Its 29 years old

 

[CR94]

Originally Posted by demarpaint
... An hour meter is a real eye opener, especially if you live in a Metropolitan area like NYC. That might be the best way to determine an OCI.
Yes, changing based on running time might be better than changing based on distance in those circumstances.

I suggest that changing based on fuel consumed might be better than either of those plans, under a wider variety of conditions. By "better," I mean more closely correlate with condition of the oil. Regardless of operating conditions, just change oil after burning as much fuel as hypothetically would've been burned reaching the manufacturer's maximum recommended change mileage under favorable conditions.

 

[ARB1977]

Originally Posted by Bluestream
Oil doesn't go bad sitting in CC. unless you do a lot of stop and go driving you need to only look at miles/hours not time. My BMW is on 4 year OCI. Its 29 years old

Lol. Sounds like my mother in laws 95 540 with 17K miles. The indicator bar for the oil is almost in the yellow.

 

[Bonnelvr92]

In my opinion time is a bigger thing then miles. Some people wonder why one engine runs better than the other even though the engine that runs good has more miles than the one that runs rough, but the good runner has higher miles. Some are to blame that it is how it has been kept up.with, and that is a big factor of it, but another big factor is that the one that is running rougher could have more time on it. The engine with lower miles could've idled longer than the engine that has more miles.

 

[Railrust]

I wouldn't worry about going 7-8 months if you haven't hit the mileage point. I can't see a couple extra months being a problem as long as your miles haven't exceeded the limit. To me mileage is more important than oil sitting comfortably in someone's crankcase in their garage.

Now if we're talking about a car sitting there running all the time, or a lot of miles idling in traffic, keeping the total mileage on the interval down? Then yes I'd change that oil, but if it's just because you aren't driving the car all that much, I wouldn't worry about it.

 

[bluestream]

Originally Posted by ARB1977
Originally Posted by Bluestream
Oil doesn't go bad sitting in CC. unless you do a lot of stop and go driving you need to only look at miles/hours not time. My BMW is on 4 year OCI. Its 29 years old

Lol. Sounds like my mother in laws 95 540 with 17K miles. The indicator bar for the oil is almost in the yellow.

When it gets to the red change it.