Oil Change Intervals Objectively

[pseudoid]

The entire point of why I bought the backup generator for our house from Harbor Freight is so that I don't have to care if it blows up.
If it works one time during a winter storm power outage and it keeps my heat on it'll be money well spent.

I used to go with this mentality about HarborFreight tools.
If the package of el-cheapo tap-n-die set will get one single successful use, I'd be happy!
(Of course, the titanium-coated versions, because I plan to carry them on my backpacking trips...)
But buying HarborFreight tools for "emergency-use" is just not wise, no matter what excuse we can conjure up.
I bought a very sturdy (IP67+, great look/feel) rechargeable flashlight for "emergency-use" from aliexpress.
Four months later, it stopped working crapped out after a 18650 battery exchange.
I just threw it out (kept the o-rings) and spent $80 for a REAL "emergency-use" flashlight by Inova #T7R.

Would you be willing to buy your oil from aliexpress at half the price?
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My personal BMW I use Castrol because simply I have always used Castrol with our BMW's

When you took your BMW motorcycle in for service, they had their own BMW branded ['mystery?] motor oil and you would NOT dare to ask them for anything else, because the warranty had the potential to become null&void.

 

[captainbeefheart]

I should have clarified that I use this interval for my Jeep because it sees some hard off road driving and towing, so it needs at least that interval, which in most cases is 6 months since I rarely drive it 1,000 miles a month. For my other cars, I do go further than 6,000 miles and often more like 8 or 9 months depending on distances driven.

I forgot to mention towing or off roading. In your case yes that's fine and you're smart for adhering to the rough service intervals instead of normal service intervals. Don't forget about your transmission, I'm not sure which Jeep you have but you probably have the same ZF transmission my BMW has which are probably the best transmissions in the world. ZF recommends fluid/filter change of every 50k miles regardless what the car manufacturer says afterward, BMW doesn't even list a service interval for it and considers it a lifetime fluid which is complete rubbish. With your driving conditions I would do the transmission every 30k miles and the differentials at the same time.

heir generators have actually improved a lot in recent years and are competitive with many other brands, especially their inverter generators. I do always purchase an extended warranty for things like this at HF, however, because you never know if it is going to be a lemon or not. If you get a good one there it will generally be reliable over the long haul.

You can get a Chinese knock off of the great Honda over head cam engines like the GCV160 for 1/10 the price. As you said there is a chance of getting a lemon but for the price it's well worth the gamble because I doubt anyone will get two lemons in a row so even having to replace the engine isn't a big deal at all. With that said if you don't get a lemon they are amazing deals and for the most part just as good as the Honda. There are some quality control things like the valve clearance from the factory, typically they are supposed to them a slight larger for the break in period and after maybe 30-50 hours go in and readjust them to spec. I have seen the Chinese copies come way off spec, it takes maybe half hour to adjust it's really simple, I recommend checking them new and set them for .001" larger than spec for break in, then after break in time set them to spec. I opened one up and there was zero valve clearance, the springs were under tension at TDC!!! That's bad. Other things to check are gap for ignition pickup/coil and spark plug gaps and torque. Check around various bolts/nuts as some maybe not so tight. This to me is all worth the much lower cost of a real Honda. I do have a real Honda self propelled but that's only because the first time my neighbor used his he hit a metal pipe and bent the crankshaft. He went and bought a brand new one the second I confirmed his crank was bent, he just gave me the mower for free so I split the crankcase and replaced the crank and piston, it's been running great for maybe 6 years or so now but the transmission has a slight leak. I'm trying to use a syringe to get more fluid inside but I'll probably just leave it and replace the transmission when it breaks. I don't see anyway to split and service them.

 

[norcalscott]

I forgot to mention towing or off roading...

You can get a Chinese knock...

Good advice on the generators - I am seeing more and more food truck vendors switching from Honda to HF and since they probably use generators more than anyone, if they work for them then they can work for me.

For Jeep transmission it's stick all the way for me (well at least until they stop selling manual transmissions). I changed out the stock transmission oil for Synchromesh, which many others use. It made shifting much smoother and I will probably change that after 50k or so miles. I do differentials a little more frequently since I sometimes run through river crossings and it is a good idea to change it out if there is any chance water made its way in there. For diffs I got a good deal on a case of the new Valvoline synthetic gear oil in the flexible container and it seems really good.

One oddity of Jeeps is that they also use ATF fluid in the Transfer Case - I change that every 40K and use synthetic for that, but just store brand.

 

[MRC01]

I put Mobil 1 in my lawnmower. No joke, those little engines work hard. Going to go electric but I can't kill that 25 year old machine.

That's great, and Mobil 1 is good oil, but it's not why that mower lasted so long. My mower with its GCV160 engine still runs like new after nearly 20 years, and I used to mow acres of meadows with it, many hours of running at full throttle in the hot summer sun, mowing 2-3' high meadow grass. All I ever use is the cheapest straight-weight 30 oil that I can find, which is what the manual says to use.

In fact, mineral (non-synthetic) oil has at least one advantage in air cooled engines, which contaminate the oil faster than water cooled engines. It holds contaminants in suspension better than synthetics do. That's why we don't use synthetics with most aviation piston engines, which are air cooled and contaminate the oil long before it ever gets a chance to shear or degrade. Aviation uses leaded gas, which is worse for contaminants due to lead sludge, but any air cooled engine may benefit from mineral oil.

Mike Busch has a good intuitive explanation of the tradeoffs between synthetic & mineral oil:

 

[Anthony101]

You should change your oil every year since it degrades with time. In addition to your engine oil, you should also replace your oil filter every 10,000 kilometres or every 15,000 kilometres. However, you should consult your car's owner's manual to establish your vehicle's appropriate service interval and recommended oil viscosity.

It all depends on your driving habits; if once in a while, you are going to drive from The Red Ball Garage in Manhattan to the Portofino Hotel in Redondo Beach, California, attempting to break a Cannonball record. Then yes, change your oil every 3,000 miles.

 

[Timcognito]

That's great, and Mobil 1 is good oil, but it's not why that mower lasted so long. My mower with its GCV160 engine still runs like new after nearly 20 years, and I used to mow acres of meadows with it, many hours of running at full throttle in the hot summer sun, mowing 2-3' high meadow grass. All I ever use is the cheapest straight-weight 30 oil that I can find, which is what the manual says to use.

In fact, mineral (non-synthetic) oil has at least one advantage in air cooled engines, which contaminate the oil faster than water cooled engines. It holds contaminants in suspension better than synthetics do. That's why we don't use synthetics with most aviation piston engines, which are air cooled and contaminate the oil long before it ever gets a chance to shear or degrade. Aviation uses leaded gas, which is worse for contaminants due to lead sludge, but any air cooled engine may benefit from mineral oil.

Mike Busch has a good intuitive explanation of the tradeoffs between synthetic & mineral oil:

Learn something everyday. I have 1/4 acre of Cape Wart and I just push my mower every couple weeks in the rainy season. It's pretty flat

 

[G|force]

Operating 2 filters in parallel
Thanks B88 and blueone for the liberal view of how mass produced products - oil filters should operate.
Plugging the valve inside that L24 block was young me following the printed book from Bob Sharp and Electramotive. Planters Peanuts, Canon AE-1 livery in IMSA racing.
Paul Newman didn't have that oil valve in his 30 degree rotated dry sump L28 block so I bought a tap and...

 

[captainbeefheart]

Good advice on the generators - I am seeing more and more food truck vendors switching from Honda to HF and since they probably use generators more than anyone, if they work for them then they can work for me.

For Jeep transmission it's stick all the way for me (well at least until they stop selling manual transmissions). I changed out the stock transmission oil for Synchromesh, which many others use. It made shifting much smoother and I will probably change that after 50k or so miles. I do differentials a little more frequently since I sometimes run through river crossings and it is a good idea to change it out if there is any chance water made its way in there. For diffs I got a good deal on a case of the new Valvoline synthetic gear oil in the flexible container and it seems really good.

One oddity of Jeeps is that they also use ATF fluid in the Transfer Case - I change that every 40K and use synthetic for that, but just store brand.

Most transfer cases now use ATF fluid and not gear oil, my Nissan Titan uses a blended ATF while the Jatco 5 speed uses fully synthetic. Honda/Acura use a special ATF type fluid for their rear ends because there are hydraulic pumps that control the power to each axle. A good friend had a Wrangler with a 6 speed manual and he traded it in and I don't think they offered a manual anymore so he went with the ZF 8 speed which he was blown away by and very happy he did. I get it, I love manuals for some cars but in my old age, especially towing the boat an automatic is just so much more comfortable to drive, a stick especially in traffic just kills my knee, especially if the car has a old mechanical style performance clutch.

One thing I do with all my trucks and for my friends is I extend the rear axle breather with a hose up into the rear tail light assembly. My Nissan had water getting in and ruined some bearings so when I pulled the axles I had to clean the rust and crap out. Many Dana rear axles have a little breather cap just directly on top of the axle housing, it doesn't keep much out in certain conditions. The thread is a standard pipe thread I believe, I just removed the old fitting and installed a barb fitting to clamp the breather hose to. I run them up into the tail light cavity and place a tiny fuel filter at the very end to keep debris from being breathed into the axle housing. I've driven through a lot of water with that truck and the vent hose extension was well worth the tiny amount of effort to modify it.

 

[Sal1950]

I had a drain plug fall out at 140km/h on my Suzuki 400E motorcycle. The handling was apparently suffering in a corner and so I waited till I slowed down and test hit the rear brake and almost skidded out. It was a scary ride. I've always been apprehensive about mechanics after that.

Now that sounds like fun.

I'm not even the least bit stressed going 10k miles

That's a serious mistake, but it's your car.
Pull the stick,
What color is your oil at 10k?
What does it smell like?
If it's more that just a few shades darker than new or smells like gas
Get Rid Of It.

 

[Doodski]

Now that sounds like fun.

A shop helicoil'd in a new set of threads and I was off and running for years with no issue.

 

[captainbeefheart]

That's a serious mistake, but it's your car.
Pull the stick,
What color is your oil at 10k?
What does it smell like?
If it's more that just a few shades darker than new or smells like gas
Get Rid Of It.

I don't have a dipstick on my car.

I've sent oil out for analysis and it's fine to go 10k miles, it's not an old car with a carb that blows a bunch of combustion gases by the rings.

The oil industry puts way too much stress into oil changes. Even 3k with conventional oil is ridiculous. I've had a few cars make it to half million miles and don't get rid of them until I got at least 250k but I drive a lot.

I have all my ASE certificates if that makes any difference to you; e.g. I'm not just some dude online making stuff up. I do recommend sending oil out for analysis if anyone wants real info for oil wear at a particular mileage, it's only $30 and tells you everything you need to know.

 

[Sal1950]

I have all my ASE certificates if that makes any difference to you; e.g. I'm not just some dude online making stuff up

And I'm a Master rated Auto Mechanic and Automotive Machinist, with near 40 years hands on experience.
It's your car. I never let mine go past 3k miles.

 

[Blumlein 88]

Now that sounds like fun.

That's a serious mistake, but it's your car.
Pull the stick,
What color is your oil at 10k?
What does it smell like?
If it's more that just a few shades darker than new or smells like gas
Get Rid Of It.

The only car I've purchased new, I changed the first oil at 700 miles and again at 2000 miles. Followed a break in procedure. At 2000 miles I switched to full synthetic and after reaching 10,000 miles changed it every 10,000 miles. Using Mobil 1 which was the only choice for synthetic at the time. At 130,000 miles a week before someone totaled it out for me, the old oil was barely darkened at all, and smelled like synthetic oil. I had the valve cover off to check valve adjustment at 100,000 miles and inside it everything still looked new and shiny silver. No build up maybe just the very slightest gold tint. The oil I drained from it always looked like it was a waste to change it. Mobil 1 in those days claimed you could go 25,000 miles per change (or two years) and I was tempted to at times stretch it to 15,000 miles, but never did.

They now claim 20,000 miles. With some testing to back it up.

Here's how Mobil 1 ensures it makes a 20,000-mile claim

Not all oils are created equal, and there's a new product on the market that comes with a pretty bold claim. Mobil 1 Annual Protection promises a life of 20,000 miles or one year, whichever comes first, before the oil needs to be changed. Intrigued by the claim, chief explainer Jason Fenske of...

www.motorauthority.com

 

[Blumlein 88]

Video about various poorly maintained cars brought to a shop. Several involve long oil change intervals.

 

[Sal1950]

The only car I've purchased new, I changed the first oil at 700 miles and again at 2000 miles.

That's the best insurance you can give a new engine.
Oil contamination can vary greatly from both the drivers startup/warmup acceleration/braking style, type of trips made, so much more.
I err on the safe side. Oils cheap, cars not so much.

 

[captainbeefheart]

That's the best insurance you can give a new engine.
Oil contamination can vary greatly from both the drivers startup/warmup acceleration/braking style, type of trips made, so much more.
I err on the safe side. Oils cheap, cars not so much.

Yes with a new engine but after break in period every 10k miles is more than sufficient, as he said at over 100k he tore it down and the inside was clean. I don't tell others what to do so if you feel every 3k makes you feel better that's great but honestly it's a waste. As stated you can go 20k miles and the wear analysis proves this but I once a year or every 10k miles is err on the side of caution. Oil after 10k is fine and can go another 5k easy, another member also sort of feels bad wasting it like myself but yes I like my cars so I do every 10k instead of 15-20k. Now if you drive only 3k miles in a year and you change it I understand that but the measurements show 2 years it's still fine but as you say I like my cars so once year no matter mileage or every 10k. It's nice middle ground between not wasting resources but also ensuring proper protection and performance.

I just did an oil change and still have the old oil, it was done a little over 10k miles. I'll send it out and have it analyzed and post the results. I'm curious the last time I sent it out at 7k miles to see where I was at and it was completely fine. I'll look for the paperwork and post that too.

 

[blueone]

And I'm a Master rated Auto Mechanic and Automotive Machinist, with near 40 years hands on experience.
It's your car. I never let mine go past 3k miles.

I'd like to have you as a mechanic, Sal, being so conservative and all, but I think I'll leave oil analysis to the chemists. Blackstone seems to always imply I'm leaving substantial oil life on the table by changing at 5-6K miles.

Now when it comes to transmissions, transfer cases, and differentials, I tend to be more conservative than the manufacturers specify by a long shot, what with no filters (at least on manual transmissions), lots of metal on metal action going on, and often lack of active cooling, but I'll think I'll leave the 3K oil changes to you.

 

[pseudoid]

What does it smell like?

He will only tell you if you pull his thumb!

 

[EJ3]

Well op said short and long trips, so I assumed it isn't sitting 3 months at a time.

Without engine monitoring and on full synthetic oil: I do annual oil changes. Unless the mileage goes over 15,000 miles, in which case I change the filter (always use a finer filtering filter), if I hit 25,000 miles in less than a year, the filter gets changed again, (with an oil change). Since I started using synthetics in the mid 70's this has been my method on cars that I have not increased the performance on. I have had most of my cars go over 200K & some go over 300K.

 

[captainbeefheart]

Blackstone seems to always imply I'm leaving substantial oil life on the table by changing at 5-6K miles.

That's my experience also. It's funny how the industry has us brainwashed to "every 3k miles" which was excessive with even conventional oil. For your average passenger vehicle I did 5-6k on conventional and doing tear downs for timing chains guides or whatever showed nice clean internals. I've never had an engine fail and most ran up to 300k before too many other issues set in which in New England is almost always rust and rotting. Fast forward to today with synthetic element filters and high quality synthetic oils and 10-15k easy is totally fine.

Now when it comes to transmissions, transfer cases, and differentials, I tend to be more conservative than the manufacturers specify by a long shot, what with no filters (at least on manual transmissions), lots of metal on metal action going on, and often lack of active cooling, but I'll think I'll leave the 3K oil changes to you.

Bingo!! People focus far too much on engine oil yet never touch their transmissions or differential/transfer case's. Automatic transmissions to this day still use a blended formula in most standard passenger vehicles. If the OEM fluid is a blend and their is a full synthetic available I'll switch over to full synthetic. The Valvoline Max-Life multi-vehicle ATF is actually really high quality transmission fluid. Many somewhat older cars which ran conventional ATF or even a blended ATF are happier with the swap and it's not expensive at all. There are many transmissions I will not use a universal fluid for like the Chevrolet 8L45 or 8L90, which can only run 1 type of fluid made by Mobil (LV ATF HP that replaces Dex HP) and that's it. Use anything else and those transmissions will not run right and fail early. The amount of metal wear on the magnets and on the bottom of the pan when servicing transmissions makes me want to start servicing them every 30k instead of 50k. A transmission swap costs about the same as an engine swap so I never understood the person that does engine oil every 3k religiously yet their transmission is running on the factory fluid at 100k miles.