Recommended Oil change intervals

[TheLandYacht]

Question(s) regarding oil change interval and the definition of "Normal" and "Extreme".

A bit of background.

I own a 2018 Mirage SE stock (purchased a bit over a month ago with just a bit under 10k miles on it).

I drive it 40 miles each way commute each night almost entirely (95%) highway @ 65-70mph.
The route is through the Texas Hillcountry, and it's hilly enough that it effects my gas mileage to the point that my calculated mileage is hovering around 35-36mpg after 2k miles.
I use Cruise Control religiously, and use it for acceleration & deceleration when/where I can too.
My route & cruise keeps my RPMs between 2.5k & 3k for the most part.
I accelerate gently (I think, I learned that on my previous vehicle...a prius). Rarely above 3.5k RPM unless I'm getting out of someone's way or passing somebody.

BUT...

This IS Central Texas, where we've had a stupid number of 100+ (Fahrenheit) days this summer already.

So, with the amount of highway driving & the high temps...am I "Extreme", or do I follow the "Normal" schedule?



On an unrelated matter, I've thought about using Fuelly (since coming on this forum, I see lots of people using it)...but my wife & I share this vehicle for commuting...so we both fill it up. How would that work for tracking fuel purchases & mileage? Or can you put 2 accounts on one car somehow in Fuelly?

[Mark]

Question(s) regarding oil change interval and the definition of "Normal" and "Extreme".

A bit of background.

I own a 2018 Mirage SE stock (purchased a bit over a month ago with just a bit under 10k miles on it).

I drive it 40 miles each way commute each night almost entirely (95%) highway @ 65-70mph.
The route is through the Texas Hillcountry, and it's hilly enough that it effects my gas mileage to the point that my calculated mileage is hovering around 35-36mpg after 2k miles.
I use Cruise Control religiously, and use it for acceleration & deceleration when/where I can too.
My route & cruise keeps my RPMs between 2.5k & 3k for the most part.
I accelerate gently (I think, I learned that on my previous vehicle...a prius). Rarely above 3.5k RPM unless I'm getting out of someone's way or passing somebody.

BUT...

This IS Central Texas, where we've had a stupid number of 100+ (Fahrenheit) days this summer already.

So, with the amount of highway driving & the high temps...am I "Extreme", or do I follow the "Normal" schedule?



On an unrelated matter, I've thought about using Fuelly (since coming on this forum, I see lots of people using it)...but my wife & I share this vehicle for commuting...so we both fill it up. How would that work for tracking fuel purchases & mileage? Or can you put 2 accounts on one car somehow in Fuelly?

Steve's "cheap plastic car thread" did quite well with 5,000 mile oil changes. Even though his Mitsubishi dealership closed their doors, their nearby Cadillac dealership honored his lifetime free oil changes.

Steve received about 55+ free oil/filter changes before doing the final ones himself. They used 5W30 conventional oil each time, and his engine had zero issues when he sold it @ 307,000+ miles recently.

Since switching from 3,000 mile conventional oil changes in former vehicles, I have gone to 5,000 mile synthetic oil changes for my current ones. I also use a good mid-grade oil filter. My local mechanics also recommend 5,000 mile synthetic oil changes for our driving school vehicles. The two Mirage maintenance schedules recommend 3,750 or 7,500 mile oil change intervals. 5,000 miles sort of splits the difference. I like 5,000 mile changes, because it's super simple/easy to remember. Every 5,000 miles I change my oil/filter, check my engine air filter & cabin air filter. I clean or change those as necessary.

If Steve's car did well with 5W30 conventional oil changed every 5,000 miles, I figure synthetic oil changed every 5,000 miles should do just as well or better. It's only 3 quarts of oil in a Mirage. I see no need to keep it in there forever. If I did strictly all highway miles during moderate temperatures, 7,500 mile intervals would most likely be perfectly fine, too.

It comes down to how much TLC you want to give your car. If you change vehicles often, you may be inclined to do things differently. I would like to keep my Mirage as long as possible. I am willing to give it some extra TLC in the meantime.

A person needs to do what they feel is right. 0W20 is sort of a North American thing (for improved fuel economy). Various oils are recommended in other markets . I am not convinced 0W20 offers superior engine protection during hot conditions, but no one needs to agree with me.

If I live in a warmer climate, I would use 5W30 synthetic oil but that's me. It's not recommended for the North America market, but I find that to be a bit silly. Once again, a person should do what they feel is best. I live in Wisconsin, & I feel better using 5W30 during the summer months. I don't mean to cloud the issue, however.

I surely don't blame anyone for sticking with 0W20 oil. I'm just not that hung up on it. I sort of base that on Steve's experience with his Mirage, too. He lives in Louisiana (also a southern state).

Steve & I also owned/own 5-speed manuals. All of my vehicles have been manuals (starting with my used 1978 Honda Civic wagon during my college years).

[7milesout]

So, with the amount of highway driving & the high temps...am I "Extreme", or do I follow the "Normal" schedule?

Normal.

On an unrelated matter, I've thought about using Fuelly (since coming on this forum, I see lots of people using it)...but my wife & I share this vehicle for commuting...so we both fill it up. How would that work for tracking fuel purchases & mileage? Or can you put 2 accounts on one car somehow in Fuelly?

It's only going to work well if you command your subordinate to enter the information into fuelly. But since she probably couldn't have a duplicate fuelly account on her phone accessing the same account as you (maybe, not sure if that could be worked out or not), it could be the only way to do this is for her to snap a picture of the gallons required to fill, and snap a picture of the odometer. Then you can have her send you the pics or jump on her phone and covert the info to your fuelly.

Best case is to buy her some ole crusty / hooptie Hyundai Accent and discontinue allowing your subordinate to drive your Mirage.

[TheLandYacht]

SNIP...my wife & I share...SNIP

SNIP...command your subordinate...SNIP

HAHAHAHAHAHAHAHAHAHAHAH!!!!!!!!!!!!

Deep breath....

HAHAHAHAHAHAHAHAHAHAHAH!!!!!!!!!!!!

Now I need to go hide that response before my "subordinate" sees it.

[TheLandYacht]

Now I need to go hide that response before my "subordinate" sees it.

Is this allowed? Let me know if not & I'll get rid of it.

[foama]

Every now and then I connect an external thermometer to the oil filter and measure the oil temp in various conditions. The sensor touches the filter can and is wrapped with a rag to ensure it measures accurately. I recommend checking for your own confidence.

On a multi-hour Autobahn trip in 40°C weather, the oil temp never exceeds 75°C.
In cooler weather on half-hour trips, it would reach about 65°C.

That tells me the heat-exchange oil/water in our cars is excellent and was designed perfectly!



For comparison:
On a similar-sized 3-cylinder GM car in the same highway conditions, oil will easily reach 140°C and above, and on short half-hour trips 80°C is typical.




I change the fully synthetic oil when it becomes almost as brown as soy sauce, usually around 12000km (8000miles). Actually it should be perfectly OK to run it twice as long.
The same oil in VW and BMW will last up to 50000km as dictated by the computerized oil service gauge.
On some GM 3 cylinder cars (Corsa), 30000km/ each 2 years is what the manual says. Their timing chains are notorious for needing replacement after only 40-50000km or so. Maybe it has something to do with oil temperatures.

[TheLandYacht]

Every now and then I connect an external thermometer to the oil filter and measure the oil temp in various conditions. The sensor touches the filter can and is wrapped with a rag to ensure it measures accurately. I recommend checking for your own confidence.

On a multi-hour Autobahn trip in 40°C weather, the oil temp never exceeds 75°C.
In cooler weather on half-hour trips, it would reach about 65°C.

That tells me the heat-exchange oil/water in our cars is excellent and was designed perfectly!



For comparison:
On a similar-sized 3-cylinder GM car in the same highway conditions, oil will easily reach 140°C and above, and on short half-hour trips 80°C is typical.




I change the fully synthetic oil when it becomes almost as brown as soy sauce, usually around 12000km (8000miles). Actually it should be perfectly OK to run it twice as long.
The same oil in VW and BMW will last up to 50000km as dictated by the computerized oil service gauge.
On some GM 3 cylinder cars (Corsa), 30000km/ each 2 years is what the manual says. Their timing chains are notorious for needing replacement after only 40-50000km or so. Maybe it has something to do with oil temperatures.

Even with your well-thought-out methodology for checking oil temps, I'd be hesitant to second-guess the manufacturer on their recommendation. Certainly not to the extent of DOUBLING it...or even going far over as you're suggesting. I'd be much more likely to second-guess the manufacturer in the other direction myself. I'm a cautious man, although I wasn't always that way.

For a far more accurate read, if you were willing to go that far...I'd drill & tap a sensor into the oilpan itself or add one somewhere else in the flow-path a'la coolant temp sensors & permanently attach it...maybe have a digital gauge on the dash. That way you're not getting a external read on the filter.

[Mark]

Even with your well-thought-out methodology for checking oil temps, I'd be hesitant to second-guess the manufacturer on their recommendation. Certainly not to the extent of DOUBLING it...or even going far over as you're suggesting. I'd be much more likely to second-guess the manufacturer in the other direction myself. I'm a cautious man, although I wasn't always that way.

For a far more accurate read, if you were willing to go that far...I'd drill & tap a sensor into the oilpan itself or add one somewhere else in the flow-path a'la coolant temp sensors & permanently attach it...maybe have a digital gauge on the dash. That way you're not getting a external read on the filter.

Just adding to discussion -

If you want to keep your vehicle for a long time, I would go with your gut. I just saw this recent article posted this week -

https://www.carscoops.com/2022/08/to...gine-teardown/

I can't say I watched the 48 minute video within the article, but I agree with the mechanic's conclusion (stated below) -

"To prevent this from happening, AMD recommends changing your oil every 5,000 miles (~8,000 km) or every six months instead."

7,500-10,000 mile oil change intervals will most likely get one past their vehicle's warranty period, but is that a consumer's goal or a manufacturer's goal?

Foama may advocate for longer oil change intervals, but look at what he shared -

"On some GM 3 cylinder cars (Corsa), 30000km/ each 2 years is what the manual says. Their timing chains are notorious for needing replacement after only 40-50000km or so. Maybe it has something to do with oil temperatures."

30,000 km = approximately 18,650 mile oil change intervals. Corsa are notorious for needing timing chains replaced @ 25,000-31,000 miles (40,000-50,000 km).

I wouldn't question oil temperature. I would question the oil change intervals.

I only know of one Mirage owner having to do a timing chain replacement, & they admitted going 43,500 miles without an oil change. Those like Steve who changed their oil every 5,000 miles have had zero engine issues (with much higher mileage on their Mirage engine).

Personally, I would pick a conventional oil changed every 5,000 miles over a synthetic oil changed every 10,000 miles.

A Mirage only take 3 quarts of oil. 3 quarts of full synthetic oil is not that expensive.

Super Tech 5W30 conventional oil is approximately $3.29/quart = $9.87 for 3 quarts.
Super Tech 5W30 full synthetic oil is approximately $4.08/quart = $12.24 for 3 quarts.
Super Tech 0W20 full synthetic oil is the same price ($4.08/quart) if you are hung on that type of thing.

I don't mind paying the extra $2.37 ($12.24-$9.87) for a full synthetic oil change every 5,000 miles. Engine repairs are expensive. Replacing a car these days is depressing.

I am not a brand loyalty guy. If there is a bad full synthetic oil on the market, I am not aware of it. If you like paying extra for a brand name, there is nothing wrong with that. Some brands, however, are inferior to Super Tech. A few may be better. If you change your oil every 5,000 miles, I don't know if it matters that much.

Once again, I return to Steve's Mirage. It did very well on 5W30 conventional oil changed every 5,000 miles. I think the key here is 5,000 miles & not the oil or filter.

[TheLandYacht]

Once again, I return to Steve's Mirage. It did very well on 5W30 conventional oil changed every 5,000 miles. I think the key here is the 5,000 miles & not the oil or filter.

Something about the breakdown of viscosity of the oil over time (or miles). What little viscosity there is in 0w20 (or whatever) in the first place.

You've got little enough leeway to play with. Stretching that would seem...unwise. That's why I was wondering if I fell into the "extreme" category with my driving habits/environment. At $35 or so for supplies (and about that for labor to get someone else to get under the vehicle for me)...doing it a bit more often is WELL worth the peace of mind.

Now I'll move into the 5k mile change rotation...which is coming up pretty soon. I put 80 miles on it every night.

[Fummins]

Agreed. I can't say I've ever seen many engine problems caused by changing the oil too often.Attachment 24060Attachment 24061