4,000 mile oil change interval (with Synthetic) from now on.

Joined
Oct 9, 2004
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What is gained by pushing OCI to 10k? Only gain I see is $50-100 a year. Take the Honda Accord with the 1.5L turbo. Huge oil dilution issue. Honda says 10k. The general public will do that. Knowing what I know now, I would change at 5k. My own Accord, not turbo but direct injection, I did 10k OCI. Car consumes oil. Decided to bring it down to 5k. The heck with wasting oil that may have useful life. If anyone here wants to pay shipping, I'd be happy to give you my very expensive used oil for free...it only has 5k on it, you can squeeze out at least another 5k from it.

This is obviously not going to change minds. I'm of the mind set 5k is good enough for me. Maybe go longer if for instance its Jan/Feb and I'm too lazy to change oil in the freezing temps.

The fact that there is a forum dedicated to this tells me all I need to know about us...OCD nutjobs :)
A resource we can’t buy, Time. I check the oil level every1k miles while fueling. I have tires rotated every 5 k and maintain brakes, transmission,differentials, xfercase & drive shaft grease points on schedule.

cooling And lubrication systems current vehicles are,better than ever.
 
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Here is the 2.0T in my 2017 Audi. This pic is at 70k when I did the oil separator/pcv. At this point it had 6 10k oci and two 5k (winter short tripping). Its past 90k now and timing chain readings with obdeleven are well within spec. I've used 0w-40 Castrol Edge and Ravenol. I can't see where 10k oci is hurting anything here.
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SammyChevelleTypeS3

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Here is the 2.0T in my 2017 Audi. This pic is at 70k when I did the oil separator/pcv. At this point it had 6 10k oci and two 5k (winter short tripping). Its past 90k now and timing chain readings with obdeleven are well within spec. I've used 0w-40 Castrol Edge and Ravenol. I can't see where 10k oci is hurting anything here. View attachment 76761 View attachment 76762
AWESOME looking. Does the manufacturer call for 0w20 or 0w40 or???
 
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eastern WA
The machine serving People. Not people serving machines when Additional practical utility is not being gained. Mostmof the reasoning for over servicing is to make the owner feel more secure when the act of using the vehicle puts the vehicles longevity (collisions) at more risk than any service interval can on terms of probability. not may now be more likely to lose our vehicles to damage or degraded enjoyment in ride or features from time than mechanical failure Associated with following factory Recomended service intervals.
an analogy I have is service rifles in the military being serviced (cleaned to The point of excess)for the armorers need to display, but with little effect on service life which was based largely on rounds fired.
this is a very insightful post. as a former US Army unit armorer, I concur 100%. As a side note, Vilseck is fantastic!
 
Joined
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Danville, Indiana
Conceptualize it however you'd like, its still a waste.

I used to do 3k OCI's with my vehicles until probably my 99 Silverado 5.3, when I started to use the OLM and started doing longer OCI's. I sold that Silverado and it still runs at over 300k miles. I saw an old Jeep YJ 2.5 with nearly 500k on it running great. It had a life of 3k oil changes.

I think the engines that wear out are those that are neglected, not those that someone pampers. That's been what I've observed over my lifetime. And usually the ones neglected have the rest of the car fall apart before the engine wears out, but I have seen a couple lay down some smoke screens, too, either having oil in there too long or by having oil level drop to a critical level due to not checking it.

I'd say do what makes you feel good, but don't go beyond the OEM's recommendations. We can all fuss and opine all day over the intervals between 3k and 10k or whatever the OEM says. I've not heard of anyone going less than 3k, outside of folks who run their cars at the track.

I have settled in on 5k on my 2018 Jeep's Pentastar because it is easy, only takes 5 quarts, and I enjoy messing with it. But I've run over 8k and the oil was in great shape with a strong TBN number at that point (3.9). I'm sure it would handle 10k on my favorite oil, Mobil 1 EP, with no issues. But I like changing it at 5k.
 

SammyChevelleTypeS3

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Never forget reading a story about Steve McQueen (another machine/auto lover) when he was in the military.


John Farthing
, former Former British Army Soldier
Answered Aug 31, 2021 · Author has 77 answers and 311.3K answer views

I did hear on a biography program that the legendary Steve McQueen was drafted to an armored unit in the US Marine Corps using later mark M4 Sherman medium tanks. Being an all round vehicle nut and petrol head, Private McQueen stripped and then rebuilt his tank engine and transmission, taking off all the limiters and boosting output. It was said that his M4 was “the fastest in the Western Alliance”!
The version I heard was after he did all that work, the tank ran exactly as it did before he overhauled it.
 

pbm

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I was a 3K OCI guy before joining BITOG. Over the last several years I started to bravely extend my OCI's to 5K on dino and approximately 7K (8K being the most I've ever gone) on synthetic. I've seen no difference in cleanliness or wear since extending my OCI's except that the GDI 2.0 in my 2014 Focus does darken the oil much quicker than the non GDI 2.5 in my 2016 Escape.

It seems that just as I get brave enough to extend my OCI's they come out with technology that makes that a bad idea. I still haven't decided on an OCI for my daughters new Mazda 2.5 Skyactive (non-turbo) but I'm leaning toward 6 months or 6500 miles whichever comes first although I see many on here are doing 5K changes. Tell me if you think a 6500 mile OCI is a bad idea on this Mazda using 0w20 synthetic?
 
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I have been doing 10K OCIs with M1 oils for the last 43 years in many types of engines and have never had any(meaning zero) engines with sludge or varnish. Some engines with over 200k and one with 354K. Here is an example of my current 2007 Ford Fusion when it had around 195K. The engine now has 280K with no oil consumption and no signs of engine wear.
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SammyChevelleTypeS3

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I have been doing 10K OCIs with M1 oils for the last 43 years in many types of engines and have never had any(meaning zero) engines with sludge or varnish. Some engines with over 200k and one with 354K. Here is an example of my current 2007 Ford Fusion when it had around 195K. The engine now has 280K with no oil consumption and no signs of engine wear. View attachment 76788
One of my brothers has used M1 oil all his life in every vehicle. He used to save used oil to show me what it looked like when drained.
It was pretty amazing. He never needed any engine related repairs. He did mention to me around the late 1990s that M1 changed something and his oil does not look like it used to after being used. He is still using it with no problems yet. This photo is very impressive.
 
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I alternate between 5k and 10k. I just look at the odo to tell me if it needs something or not. I find my FWD’s “need” a tire rotation every 5k; wife’s new car is DI so it’ll get oil changes every 5k. Her old car I did 10k for quite a while, haven’t gotten into the motor at all so I have no idea what it looks like inside, maybe I’d be sad… but it’s over 230k now and no oil usage.

Stuff up here will rot away anyhow. Not going to overthink it.
 
Joined
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NorCal. USA
I'm someone that almost always goes about 3-5K myself, usually using "conventional" which is syn blend now anyway. 90% of my driving is city/suburban and short trip, though.

That said, people have posted sludge free immaculate valve covers with 7, 8, and even 10K oil changes here. Even on a Galant I ran with Supertech conventional most of its life for 4-7k oil changes over 50K miles, I had only light varnish when I pulled the head. On that Galant, though, I always cleaned the PCV valve every oil change and bought 1-2 new ones, and was fairly religious with new air filters every year.

Sludge 99% of the time is related more to PCV valves than any other factor I think. The other thing that seems to cause sludge sorta regardless of the oil brand is if a car has been sitting for a long time and the oil just gets old sitting around in an engine (which is a different environment than a plastic bottle.)

So oil changes are a big deal for preventing sludge, but they're not the only factor, it's imo more about complete maintenance of the car. If you have bad spark plugs and o2 sensors, or a thermostat that's perpetually stuck open, those will eventually create more sludge even with a 3K interval than you would with a 10k interval on good oil, assuming everything else in the car is working properly, PCV isn't shut, air filter is clean, etc.
So basically, it should be more based on time rather than miles. The sludge could be from short trips, engine not fully warming, etc. Just the fact the PCV was plugging indicated sludge and deposit formation. Once the deposit holding capacity of the oil is reached, deposits start dropping out of suspension.

I would rather buy a cheaper (Dexos) oil and change it out more often, than buy the higher priced oil and try to stretch it out.
 

SammyChevelleTypeS3

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I would rather buy a cheaper (Dexos) oil and change it out more often, than buy the higher priced oil and try to stretch it out.

I always cleaned the PCV valve every oil change and bought 1-2 new ones, and was fairly religious with new air filters every year. sludge 99% of the time is related more to PCV valves than any other factor I think. So oil changes are a big deal for preventing sludge, but they're not the only factor, it's imo more about complete maintenance of the car.
I agree that many factors come into play when talking engine sludge. Complete predictive / preventive maintenance of a car has a lot to do with its troubled or trouble free life span. Of course history comes into play as well if you talking a used vehicle. We don't know most of the time what previous owners did as far as maintenance or even misuse / abuse.
 
Joined
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I agree that many factors come into play when talking engine sludge. Complete predictive / preventive maintenance of a car has a lot to do with its troubled or trouble free life span. Of course history comes into play as well if you talking a used vehicle. We don't know most of the time what previous owners did as far as maintenance or even misuse / abuse.
Yes!! In 2000 or 2001 I bought an ‘88 Beretta with 80,000 miles. Great, right? Not so much. The inside of that engine was filthy. I bought it from the second owner (who thought it was an ‘89), the original owner was a teacher who apparently lived very close to work.

Timing chain jumped at 120,000, i junked it. At least I got 40,000 out of it. Lol
 
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