SOT: oil change interval, newer car with full synthetic Options

[fixer34]

My wife's 2020 Mitsubishi SUV is coming up on 2 years since the last oil change. By the odometer, she has driven a little over 7000 miles. Car gets driven regularly, but short trips. Some 20-30 mins in length every couple weeks so we know the engine gets up to temperature. Oil is full synthetic.
Am I pushing the limits here (or over them), or get to the 2yr/8000 mile mark OK?

Just checked and the level is still over the Full line (they must have overfilled a bit..)

[technicalninja]

10-15 k is fine and up to 5 years on "fully" synthetic.

Non-high rpm and non-boosted. Appliance vehicles is what I'm talking about.

Synthetic "blend" can be 1% synthetic so "blend" doesn't mean shit...

5-6K on dyno oil and less than 2 years.

I sell ONLY Mobil 1 as its very close to the price of dyno and it works great.

[Superhawk996]

I regularly do 7k between oil changes and don’t even give it a second thought. I run Mobil 1 in all my appliance vehicles.

The only thing that concerns me is the “granny cycle” short trips and the idea an occasional 20-30 min is a long enough trip to get it up to temp. Even when it’s up to temp, it takes time to evaporate out the condensation.

Short cycles are a severe duty cycle in most situations and you should be watching for signs of condensation and/or sludging. A whole lot less likely with synthetic.

Watch for whitish / milky / creamy /froth on bottom side of oil filler cap. Even better yet if you can see any of the valvetrain through the filler hole to verify it’s all clean looking in there.

[fixer34]

I regularly do 7k between oil changes and don’t even give it a second thought. I run Mobil 1 in all my appliance vehicles.

The only thing that concerns me is the “granny cycle” short trips and the idea an occasional 20-30 min is a long enough trip to get it up to temp. Even when it’s up to temp, it takes time to evaporate out the condensation.

Short cycles are a severe duty cycle in most situations and you should be watching for signs of condensation and/or sludging. A whole lot less likely with synthetic.

Watch for whitish / milky / creamy /froth on bottom side of oil filler cap. Even better yet if you can see any of the valvetrain through the filler hole to verify it’s all clean looking in there.

Not sure my wife would be happy with the "granny cycle" comment, although she wouldn't mind being a granny sometime soon...
Oil on the dipstick, oil cap, and what I can see of the valve train all look fine, nice and clean.
Thanks, I'll keep an eye on it but not worry.

[windforfun]

"Watch for whitish / milky / creamy /froth on bottom side of oil filler cap. Even better yet if you can see any of the valvetrain through the filler hole to verify it’s all clean looking in there."

Nope, sort of. This usually indicates a crack in the water jacket in the crankcase.

[emerygt350]

My new project, the mini. Has a 16000 mile oil interval. I suspect after not getting the engine nice and toasty for 16k I am going to see milk in the oil cap...

If you have synth and you are not abusing it, I would go as long as you can. You can see when oil is starting to lose its edge.

After my rebuild on the 914 i am shocked at how good the oil looks after 5000 miles and that is an air cooled monstrosity.

[brant]

I’ll just say it
What does it hurt to do an oil change after that much time.

I do often

[Superhawk996]

I’ll just say it
What does it hurt to do an oil change after that much time.

I do often

Not sure what you mean. Sure you can change oil every 1000 miles if you want. Just a waste of money. I’d also say a waste of resources but oil is highly recycled so if you want to change it, there is someone out there that will be happy to take it from you.

Synthetics, modern materials, and modern machine tool tolerances have changed the game. I’ve seen tons of dyno testing and engine tear downs using OEM recommended oil change intervals which are way longer than the old wives tale 3 months/3,000 miles we were all told by grandpa. Likewise I’ve done oil analysis on my own vehicles and have no bones with 7k interval.

You can guess and dump frequently or you can be guided by oil analysis and data.

Do what makes you happy.

[technicalninja]

I have a strange friend...

Blake is a Fiero nut first of all.

Blake became an Amsoil dealer and wanted to "prove" Amsoil's claim of 15k intervals.

3 cars, a 87 Fiero 2.8l V6, a 12 Prius driven by his wife softly (many miles electric only), and a 07 Pontiac GXP 5.3l V8.

First set of Blackstone lab tests on Castrol GTX: 2500/5000/7500/10,000
All three cars came back "OK to continue use at 7500" and all three failed at 10K "Change oil".

Loss of the additive package was reason for failure.

Same cars, Amsoil, and 5K intervals as the test were getting expensive.

All three came back "OK to continue use" at 20K!!!

Didn't matter what type of vehicle. The old Fiero matched the new Prius on the tests.

Amsoil can go 15k like they advertise.

Amsoil sent Blake reems of "test data" regarding why to buy Amsoil when he became a dealer. Their testing methods and data was interesting to read.

Amsoil's testing showed the Amsoil was better than everyone else (go figure) but what it really showed was that ALL of the fully synthetic oils were in a different class than dino based oils.

Everyone's synthetic was VERY good!

Mobil 1 was usually 2nd or 3rd place but it's 2 to 3 times less expensive than the Amsoil products.

All in all, Blake's and Amsoil's testing made me into a Mobil1 believer!!!

I stock NO Amsoil engine oil and have nearly 50 gallons on Mobil1 on hand.

I'm guessing that is NOT what Amsoil had in mind...

[targa72e]

Two studies over 20 years ago switched me to synthetic. SAE used to have a monthly publication (maybe they still do). This publication was full or articles and real world tests. I could find the magazine in the School library at Michigan State when my wife was doing Graduate work.
Once study was on over the road trucks and rear differentials . They split the fleet in to two groups. One got synthetic the other got regular dino oil. Both were same grades and specs. They dissembled the differentials every 100K miles and measured wear and changed the fluid. the test ran for 10 100K cycles. At the end of the test the synthetic trucks had less wear on the differential than the dino oil at 100K.
Second test was on a fleet of taxis. one group got synthetic other got dino oil. At the end of the test the synthetic went much further between need to rebuild the engine but it was determined there was no economic benefit as the added cost of synesthetics (at the time) over the life of the vehicle equaled the cost per mile for earlier rebuild. For most people the longer life would be a benefit.
Those to articles convinced me and I have only used synthetic since then. I have also done some of my own experiments an test and validated synthetic as the only choice.

That said , I would not have any problems with 8K change interval with synthetic on a car that is driven regularly. My only exception is that I think its a good idea to do an oil change on a new car (or rebuilt engine) when you have around 1K miles to get rid of all the debris from break in and manufacturing.

john

[mb911]

My sons 24 civic we change at 40% oil life, use Honda filters and he drives a lot. He buys penzoil synthetic. I use to run amsoil in everything but it too expensive. I run it in my GMC with a 5.3 and also change 40% but I am getting rid of that POS this week and leaving GM forever after owning mostly GM vehicles since the mid 90s in favor of a Tundra. That will get frequent oil changes at 40% as well. The -6 I use GTX classic with an added zddp supplement. That gets changed at 1K as that’s about a year . Wish I could afford amsoil in that car but darn near have to take a loan for that much oil lol

[brant]

I’ll just say it
What does it hurt to do an oil change after that much time.

I do often

Not sure what you mean. Sure you can change oil every 1000 miles if you want. Just a waste of money. I’d also say a waste of resources but oil is highly recycled so if you want to change it, there is someone out there that will be happy to take it from you.

Synthetics, modern materials, and modern machine tool tolerances have changed the game. I’ve seen tons of dyno testing and engine tear downs using OEM recommended oil change intervals which are way longer than the old wives tale 3 months/3,000 miles we were all told by grandpa. Likewise I’ve done oil analysis on my own vehicles and have no bones with 7k interval.

You can guess and dump frequently or you can be guided by oil analysis and data.

Do what makes you happy.

Your responses have become a bit aggressive and insulting lately

You certainly don’t have to follow any persons advice
But I don’t see anything hard to understand in my post

Oil analyst is a great idea
But 99.9 percent of the people reading this will not bother
The analysis itself is most of the price of an oil change

I’ve myself scored a crank that had a contaminant in the oil cycling around
An oil change is a safe and cheap way to get contaminants out

2 years old
Enough miles
Can not hurt

Don’t have to agree
But my advice is easy enough to understand
And is not harmful


Brant

[Superhawk996]

Your responses have become a bit aggressive and insulting lately

I sort of took your response the same way.

Sorry, wasn’t my intent to be overly aggressive but did want to defend the position that oil change intervals can be much longer on modern engines which is backed by data and OEM durability testing at those extend oil change intervals.

Oil analysis is $35. If it allows you to skip just one oil change, it has paid for itself and then you actually know what is going on rather than just dumping serviceable oil. Just a different way of doing things than following the 3 month / 3,000 miles dogma.

Oil analysis will report on water and/or coolant in oil therefore not guessing which could be especially useful information in a situation like OP where the car is driving short cycles.

[mlindner]

Fixer, short trips are harder on the engine then long. Change at least every year. Best, Mark

[Jack Standz]

Used to ride a sports bike. The engine shared its oil with the transmission. Always used full synthetic after break in.

For those that have ridden such a bike, you know you can actully feel the difference between old oil that is dirty or has lost its lubricity. Change the old oil and you can immediately feel the shifting and operation improve. So, just because you supposedly can go extended miles between changes per the manufacturer's claims, doesn't mean it has no effects. Particularly, if your air filter allows dirt into the motor or you ride in dusty conditions.

For those reasons, our oil change mantra is "sooner rather than later."