Synthetic Oil

[Pathfinder76]

Can someone give my a definitive oil change interval when using synthetic oil? I can’t seem to find two people, mechanic or otherwise, that agree on the subject.

[gloszz]

It honestly depends on your car and the oil. I change mine every 10,000 km as I run some high performance oil. There are some oils that you can change every 25,000 km but that is iffy as some cars may burn oil without real cause. I would say 5-10k km is a safe number.

Source: My dad who is a mechanic and has his own shop for 25 years.

[bigfis]

Check your owners manual. Intervolt is the same regardless of conventional or synthetic .

[Little red riding hood]

You can double your miles if you're running a top quality synthetic oil (amsoil, castrol) in conjunction with a spinner.

No spinner... No extended oil change.

[Tom Pullings]

Usually I run conventional oil and follow the oil life monitor but occasionally if I feel the need to run a synthetic I’ll run it double the OLM. Even if your vehicle doesn’t burn oil you should still check occasionally.

[elkhunter11]

It depends on the filter you use, and how often you change it. In general. you can extend your oil change intervals if you use a higher capacity filter, or change it between oil changes.

[CaberTosser]

5000m/8000 km is what the dealers and oil change shops want you to do, look up your vehicles actual factory manual and it will show something a fair bit longer.

I do my own maintenance on anything off warranty (everything we have,) and I have a trick where I put rare earth magnets adjacent the drain plug on the oil pan as well some on the oil filter. Remove the magnet adjacent the drain plug prior to draining, amd swap the magnets on the old filter over to the new filter when changing that. Just a little more peace of mind and it can catch the smallest particles imaginable.

[Salavee]

I've been using Amsoil or Mobil 1 with NAPA gold filters for years in all my vehicles and have never had an issue using 10-12,000 km as a change interval. As I understand it, the Gov't mandated a reduction in zinc content for all oils so probably best to consult your owners manual and use the proper specification. Not all synthetics are equal.

[dmac111]

Go by your owners manual. Synthetic or conventional... the kms outlined are what is required by the manufacturer. The manufacturer can decline a warranty claim on engine failure if oil changes are not done on time.


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[Birdy]

I’ve been using Amsoil pretty much exclusively in my Tacoma from day one and just passed 375000km. Not the high kms a lot of guys have on their diesels, but she’s been good to me and I haven’t had a single engine issue (touch wood). I’ve regularly gone 40-50000 between changes with the filter changed every 5-7000.


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[nast70]

I do my own maintenance on anything off warranty (everything we have,) and I have a trick where I put rare earth magnets adjacent the drain plug on the oil pan as well Sam on the oil filter. Remove the magnet adjacent the drain plug prior to draining, amd swap the magnets on the old filter over to the new filter when changing that. Just a little more peace of mind and it can catch the smallest particles imaginable.

That's a neat idea. I do the oil changes on my ATV's, not my vehicles, so I've never actual seen a vehicles oil plug. The ATV plugs have magnets in them to catch the fine particles, don't cars as well?

[Tom Pullings]

Originally Posted by nast70

I do my own maintenance on anything off warranty (everything we have,) and I have a trick where I put rare earth magnets adjacent the drain plug on the oil pan as well Sam on the oil filter. Remove the magnet adjacent the drain plug prior to draining, amd swap the magnets on the old filter over to the new filter when changing that. Just a little more peace of mind and it can catch the smallest particles imaginable.



That's a neat idea. I do the oil changes on my ATV's, not my vehicles, so I've never actual seen a vehicles oil plug. The ATV plugs have magnets in them to catch the fine particles, don't cars as well?

Some do. You can buy a magnetic plug for any vehicle.


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[Arty]

Minimum frequency according to user's manual. More often is better.

Synthetic allows you to go a bit longer between changes, compared to regular, because synthetic oil doesn't break down as quick. But I have no use for synthetic as I change often, just to keep suspended & dissolved junk out of the engine.

Better to wait for the 3 times a year that castrol or shell is on special at C-Tire, get that, and change often. And use high-grade OEM filters when you're doing it.

Auto trans fluid is a different can of worms, because that is relatively sealed off compared to engine oil. Tranny oil will break down before it gets dirty.

[Gray Wolf]

Originally Posted by chuck

Can someone give my a definitive oil change interval when using synthetic oil? I can’t seem to find two people, mechanic or otherwise, that agree on the subject.

Over 12 posts later, and you're still no farther ahead - probably because what you're asking for doesn't exist.

Firstly: Synthetic oil (even the stupidly expensive brands) are not the Holy Grail some like to make it out to be.

Lastly: When in doubt, crack open your owner's manual. You'll be shocked & amazed with what's hidden there!

[Little red riding hood]

Magnets are a great idea, they do catch any metal particulate in the oil.
However, they do nothing for the ash and soot that's produced from burning fossil fuel, and that is what breaks down the viscosity of the oil and disable the hydraulic cushioning effect of the oil in the engine bearings.
The filter takes a lot of that stuff out, but not all, a spinner will catch a lot more than a filter can, the more crap you can keep out of your oil, the longer it will last before it breaks down and loses viscosity.

[ctd]

I use to do oil anyalisis on my engines. (It does not pay for itself).
10,000km changes seem to be the balance between oil is still fine and I feel good about myself.

On my diesel running 15w40 conventional I ran it to 20,000km and the sample came back as still good to run. I did that a couple of times.

As for gas engines it was the same at 10,000km the oil was still good to run.
Do we change oil prematurely. Yup. Does it give us price of mind, yup. Does it keep people employed? Yup.

If you have a argument for or against extended or short oil changes. Explain your oil sampling procedure and results. I am curious.

[TUFFBUFF]

car/truck? diesel/gas?

Yep you'll get a lot of opinions and no cut and dry. One of the issues is the filter technology is not keeping up with the oil advancements.
The vehicle makers will say one thing and the oil makers will say another as well.
I've been running full syn in diesel pickup for years and change every 10k, if your worried change the filter at 5k and keep on truckin'.
My oil life monitor will say 25-35left - bad idea to follow those as well IMO. Also not good idea to go back and forth from syn to reg oil.

so...there is no answer really! - Google bobs the oil guy maybe he has the answer.

[32-40win]

A centrifugal filter, and filter changes will help, but, there is still fuel dilution to contend with, and that is something that no filters take out. Rare earth magnets help with metallic particles, they don't work on carbon, centrifugal filters do both. You can go a bit longer that way, but the additives do break down and fuel dilution occurs. Unless you run an oil pressure gauge, you can have a plugged filter and never know it on most vehicles, in which case you just bypass unfiltered oil. So you still have to change the filters on time. If you want to know what happens over time, you need to do oil samples, that will tell you what your engine is truly doing over time. How much time you spend on the highway vs city affects it, how much time you spend on gravel affects it and what you are towing affects it. Easy duty cycles are longer, more severe duty cycles are shorter.

[250mark1]

change as per the vehicle owners manual
not what the dealers say as they want you to change it more
to keep the dollars flowing into the stealership

[Tom Pullings]

Nobody knows more about your engine and what it can handle than the engineers who designed it. That’s why the oil life monitor is generally a good guideline.

Another thing to consider is direct injection. Many or most direct injection engines have issues with fuel dilution. This will limit the oil change interval. If your oil is gonna be 10 percent fuel after 20000kms you’ve not done yourself any favours.

[Dean2]

If you really want to know the answer get your oil analysed. What you will find out is that most vehicle do not need their oil changed anywhere near as often as people do it now. When I worked for CN back in the 70s., they did oil analysis on all their trucks. The big diesels got oil changes every 50-60,000 miles, the gas trucks usually ran 30 to 35,000 miles. CN used Esso Delvac part synthetic in both for easier winter starting. Today's oils are a whole bunch better than they were back then and the cars and trucks run much cleaner.

My Dodge V10 has 240,000 Klms on it, it gets an oil change with Mobile 1 5w30 and a Mopar filter every 25,000 Klms. I rarely need to add oil between changes. My Olds had 400,000 Klms on a V6 3.8L when I sold it and it got oil changes every 18,000 Klms with conventional oil. I didn't add oil between changes. I could list off all the vehicles I have owned over the years and all got changed somewhere between 20 and 30,000 KLms, or if they were low milers every two years. Some of those vehicles had over 500,000 KLMs when I sold them. I never had one that burned oil.

[Arty]

Originally Posted by 32-40win

[...] If you want to know what happens over time, you need to do oil samples, that will tell you what your engine is truly doing over time. [...]

Yes, I think you'd have to track a bunch of analyses on the same charge of oil over time, to see how all the components are accumulating and/or breaking down. Then compare each component to manufacturers' statistical tables to see how badly wear or other damage accelerates at that point. There is no absolute point where the engine will fail or fall off in performance, but where those will start to change non-linearly. Further, the wear and performance tables are statistical too, probably over hundreds of engines, so you'll get outliers which will crap out earlier than the average.

Like any engineering design, there is a point where wear or performance degradation is expected to accelerate substantially. For the producer or gross user that might not matter, as a project or lease might not last long enough to be impacted by the results. Or people foolishly dump an entire vehicle every couple of years anyway because they can't be bothered with maintenance - or are rich enough to not care. Or it's used to fight a war and is expected to be destroyed by the enemy within a few months of manufacture anyway.

As a long-term user/owner, my timeline is way longer, so that tiny bit of extra wear or varnish over time will add up to big problems in 25 years or whatever. Same reason for being picky about rust or transfer case changes or VCT solenoids. Whatever fluid analyses or lab you're using cannot give you an absolute judgment on whether a sample is 'still good' or not, as there is no such point. There's just different shades of grey, where somebody is making a call based on some set of assumptions.

Automakers would have gone broke a long time ago, if everybody maintained their stuff like I expect to.

[fordtruckin]

My 2017 Jeep Cherokee didn't have an oil change interval listed in the owners manual. I asked the service folks at the dealer I bought it from and they said to use the 3000 mile interval. When I asked why do they have the oil life monitor on the vehicles monitor and he said that was for ideal conditions, in reality they claimed how I drive in Montana is considered extreme service thus the 3000. I called BS and have it changed at 7000 miles. Even then I still have 30% left on the oil life monitor. With today's oils and engine components I agree 3000 miles is probably overkill, especially on a diesel where your adding 15 quarts. I figure as long as I keep it at a regular interval of decent intervall and use good oil with a good filter that's more important than if I go 100 miles over etc.. Generally my work truck I do 5000 miles per company policy and my personal truck I do 4000 miles. The jeep gets it at 7000, Toyota at 5000 miles. Only the Jeep gets synthetic. The rest gets conventional.

[sewerrat]

CBC Marketplace did a story about oil changes a few weeks ago. Pretty interesting.
http://www.cbc.ca/marketplace/episod...-change-debate

You might want to skip the first part of the clip unless you are into make-up.

[lakerman]

2010-18, toyota 5th generation 4 runners have the same engine but in the manuals the oil changes vary from 10 to 16000 kms, while (the oil filter is only good for 1/2 of this according to the oil filter manufactures), never heard of just changing the filter in this time frame.

[abenaki-warrior]

I use mobile 1 0w20 full synthetic in my 2015 ecoboost. Motocraft filter. Change the oil when the cange oil comes on at around 15-16000 k.

[Chuck_Wagon]

Sometimes I extend my oil changes using synthetic oils, but that isn't the purpose of it to me.
I make sure I change the oil to synthetic in both my trucks in the fall, one a diesel, other a gasser, for its cold weather starting ability in order to look after my engines. That's what counts.

[RZR]

Save your money with the synthetic oil!

[Arty]

Originally Posted by Chuck_Wagon

[...]
for its cold weather starting ability[...]

If you mean rated viscosity at a particular temperature, for any particular number the 'regular' oil and synthetic will be the same when new. That's why they have ratings. 10w-30 will be the same as 10w-30, and 15w-40 will be the same as 15w-40..

[marlin1]

in our fleet its 8k on synthetic , bus fleet with aux vehicle support . Buses go 5 mostly cause brakes don't last