Automotive oil changes

[Ashful]

Conventional wisdom, dad’s era: Change oil every x,xxx miles (usually 3,000) or 6 months, whichever comes first.

My understanding was the mileage limit was to account for breakdown of Dino oil in that engine, and the 6 months was to remove the blow-by contaminates that cause crank case and valve train corrosion. Not to mention the chunks of lava rock looking crap that we’d find grown around the push rods and rockers on cars that didn’t get frequent-enough oil changes.

Now today, most of our cars have electronic oil change indicators, which track oil life as a function of actual running conditions. Others who don’t are doing 7500 or sometimes even 10k mile oil changes that may put their change interval at greater than 12 months!

No issues with breakdown, given modern lubricants, but what about those blow-by contaminants? Yes, blow-by may be reduced in some modern engines, but it may also be higher in others, and having combustion contaminants sitting in the crank case for periods of a year or more may not be the best thing for your engine.

I drive all of my cars less than 5k miles per year, so I’ve just been doing 6 month oil changes, despite the actual mileage. Seems cheap enough and quick enough to not really even question, and I’m sure I’ll continue doing just that, but my curiosity is piqued. How is it suddenly okay to let the same oil sit in your crankcase for indefinite time, maybe even 5 years by the book, if you only put 1k miles on a car per year?

 

[therealdbeau]

Modern rule of thumb is x,xxx mileage (determined by vehicle) or 1 year. I haven't seen anyone suggest leaving oil in there for more than a year. Also, don't forget about the oil filter. It's there to prevent contaminants from getting to the motor.

 

[SpaceBus]

If in doubt, send a sample of your oil to Blackstone Labs. They have a kit you order with specimen containers, etc. After collecting samples, usually from the oil filter, you send it back to Blackstone and they analyze the oil and send you results. They say with modern top tier base stock sythentic oils you can easily go 7,500 if not more miles between changes. I keep it around 7,500 or anuallly. Blowby is trapped in the filter. Only tiny, less than 5-15 microns, pieces of metal stay suspended in the oil, which is why you have to change it. If you don't, the oil breaks down and leaves the tiny metal in your bearings, which will eventually ruin them and your engine.

If you drive the car hard, I would definitely change the oil seasonally. Even if you don't drive the car hard, it's not a bad idea to change the oil seasonally in a cold climate. Often cold temperatures are harder on the oil than mileage. This is partially due to trying to squeeze much more viscuous oil into tiny bearing clearances in cold temperatures. The other part is just that cold temperatures break the oil down just like hot temperatures.

I'm not an engineer, but I know a lot of engineers and I went to car school at the government's (your) expense.

 

[blades]

the oil itsel;f does not break down, the various additives go south though. turbo units and any thing with variable cam timing systems best to change out every 3k miles . the turbo boost adds more blow by and the variable timing assemblies have extremely small passages in them that are easily blocked, not to mention the unbelievable tight tolerances in same.

 

[SpaceBus]

the oil itsel;f does not break down, the various additives go south though. turbo units and any thing with variable cam timing systems best to change out every 3k miles . the turbo boost adds more blow by and the variable timing assemblies have extremely small passages in them that are easily blocked, not to mention the unbelievable tight tolerances in same.

True, it's not literally the oil. I didn't think about VVT/VCT but that's an excellent point. If you have a turbo you should have a catch can. I don't think I've ever seen an OEM application that didn't have some sort of filtered crank ventilation, but perhaps some don't.

 

[brenndatomu]

How is it suddenly okay to let the same oil sit in your crankcase for indefinite time, maybe even 5 years by the book, if you only put 1k miles on a car per year?

Its not...most manufactures tell you to change every year minimum, even if the mileage is low.

 

[blades]

most egr systems oem do not have any filtering installed. as to the catch cans unless it it is properly designed - do not help much except to lighten wallet.

 

[PaulOinMA]

I follow manufacturer's recommendations. I'm on enough car web sites and enough people have posted their oil analyses to show that more frequent oil changes are not necessary.

I use full synthetic.

Both our indicators just came on. Mine because of 10,000 miles. My wife's because of one year.

Oil and filters are in the garage. Will probably do my wife's on Sunday afternoon and mine one day next week. Also have a cabin filter for my wife's Escape and cabin and and air filters for mine. Will also remove winter tires and wheels.

Cabin filter for mine takes some contortions to get to.

Both oils have to meet Ford spec. My wife's Escape takes 5W-20, and the spec is …-945-A. Mine is 5W-30, ...946-A. Can also use the newer Ford B1 spec oil, which had an additional testing specification for LSPI (low-speed pre-ignition).

Both Pennzoil and Mobil 1 are running their rebates now. I had been buying Mobile 1 Extended Performance, but bought Pennzoil Platinum Full Synthetic this time since the Mobil 1 rebate wasn't up yet.

Rebates …

https://www.pennzoil.com/en_us/prom...56b2lsLzIwMTZuZXdzbGV0dGVyLz9sb2NhbGU9ZW5fdXM

(broken link removed to https://mobiloil.com/en/promotion/mobil-promotions/mobil-1-rebate-2019)

 

[peakbagger]

Amazon has a full synthetic for quite a savings. Typical synthetics are marketed as premium,folks expect them to be expensive so they price them that way.

 

[begreen]

Rule of thumb is just that. An engine is likely to see all kinds of service. How frequently the oil gets changed should be based on how the car/truck is used and type of engine. I could go 6000 miles of highway only driving on my old Volvo and the oil still looked great. But the same engine put through daily stop and go, cold startups, etc. definitely needed an oil change at 3000 miles. Winter driving is tougher on an engine than summer driving too.

 

[Easy Livin’ 3000]

This thread really makes me want an electric car.

 

[PaulOinMA]

Friend was manager at a Tesla dealership last year. Met him and he had a Model X. Instant acceleration with full electric vehicles.

My wife has a hybrid Ford Escape. Never thought she'd be driving a hybrid, but she won it at work in 2011. Likes it a lot. New Escape will be offered as a hybrid again, and she's interested.

 

[blades]

90k on my 2016 escape 2l turbo oil gets dirty in 3k so for me that means changing oil about once a month. 223xxx on my 6.0 - oil runs everything on this unit so changes at 3k are best also . HPOP are pricy and very time consuming to replace.
likely will need to pull the heads on the 2l because of the egr system loading up the valves and the innards of the turbo with crud.

 

[begreen]

Yes, good reminder. I need to get my truck's oil changed soon.

 

[SpaceBus]

90k on my 2016 escape 2l turbo oil gets dirty in 3k so for me that means changing oil about once a month. 223xxx on my 6.0 - oil runs everything on this unit so changes at 3k are best also . HPOP are pricy and very time consuming to replace.
likely will need to pull the heads on the 2l because of the egr system loading up the valves and the innards of the turbo with crud.

Wow, lot of miles on a 6.0! I looked for a 7.3 truck last summer but found an unbeatable deal on my 06 Ram.

 

[blades]

04 250 in exceptional condition over all for my area. unfortunately my 06 250 with 160xxx body is disintegrating from the red death- luck of the draw I guess.

 

[SpaceBus]

04 250 in exceptional condition over all for my area. unfortunately my 06 250 with 160xxx body is disintegrating from the red death- luck of the draw I guess.

I bought my truck in NC to avoid this issue.

 

[Ashful]

Its not...most manufactures tell you to change every year minimum, even if the mileage is low.

How many have you specifically checked for this, to have arrived at that conclusion? I just randomly checked our owner’s manuals from two brands, and our two cars from one brand (Chrysler) did have this, while the other brand (Volvo) did not. That’s 50% of manufacturers, based on my very limited research.

SRT spec’s 6000 miles or 6 months maximum, sooner if oil life indicator demands it. That’s with Pennzoil 0W40 full synthetic specified. The Ram is 10,000 miles or 12 months maximum, this time no synthetic requirement, and again usage-based oil life indicator can override. Volvo is just 7500 miles, no time limit specified in owners manual or warranty and maintenance manual, and the oil life indicator is only mileage based (not driving style dynamic).

The way it works out, I’m doing that Volvo 3x per year, just based on mileage, but if it was driven like some of my cars...

 

[saewoody]

I run all my vehicles with synthetic oil. Have been doing that for at least 20 years. They all get the 6 month/6,000 mike oil change the n the spring and fall. Have never run into any oil related issues. I tend to drive older, high mileage cars. My current stable has a 2001 Chevy 5.3 with 160,000 (had it since 75,000), a 2004 Chevy 6.0 with 190,000, and a 2005 Nissan 1.8 with 187,000. My 2003 Chevy 5.3 in my last vehicle that got hit and totaled a year and a half ago had over 215,000 on it. Also ran a 97 Ford Explorer from 36,000 to 210,000 (until that got hit and totaled) using the same oil change schedule.

I definitely would not go over a year without an oil change no matter how low the miles were. But the way I have been doing it has certainly served me well.

And in case anybody needs an oil change, Napa is running a Great oil change deal for the month of April. It you can get regular, high mileage, or synthetic plus their height and oil filter for $22.

 

[KJamesJR]

I was always led to believe...

You can change your oil and leave it indefinitely, that is until you start your motor. As soon as it’s subject to the heat/friction the additives become comprised and begin their slow process of decomposition.

Which is why you should drive it the 5k-10k miles before the years spent or you’re not getting your money’s worth.

Most synthetics have an indefinite shelf life. Mobil actually puts an expiry date on there’s, think it’s five years, though probably just added for the sake of it.

 

[peakbagger]

My Ford and a lot of other newer vehicles look at the usage of the car to decide when to change the oil. I have to get an inspection sticker once a year for the car and usually have the oil and filter changed without the code flashing. When I or the shop forgets to reset the code its been about three months before the computer flashes a screen to change the oil. I do a lot of highway miles about 20K a year on long day trips. I work from home so not a lot of local trips and even my local trips allows the car to warm up completely which is key to oil life. I use synthetic so I ma not worried about the oil breaking down. The engine will naturally breathe in humidity just sitting there and that humidity gets in the oil and combustion byproducts that leak past the piston rings can form acids in the oil. If the car is run long enough that humidity gets driven off from the engine and other components. Talk to anyone who does exhaust systems and they sell a lot more exhausts that rotted out to low mileage "granny car" then high mileage cars.

Oil should be changed based on hours of operation modified by number of engine starts and number of times the engine is short cycled where it doesn't get to full temperature . If oil analysis is done the number of hours can be stretched a long time. Industrial air compressors don't have combustion but its a pretty intense application. There are (or were 10 to 15 years ago) that offered lifetime guarantees on their industrial compressors if they were operated with a lifetime lubricant which was a synthetic if the owner sent oil analysis reports on a routine basis and added an additive package on occasion when the analysis indicated it.

By the way oil can really get cooked in turobcharged engines as the center bearing of the turbo can "burn" the oil from the heat on the exhaust side when the engine is shut down. My GMC Syclone required Mobil 1 synthetic oil changes to keep the warranty valid as Mobil 1 had much higher temperature it could withstand before the oil failed. Standard recommendation with turbo engines is let the engine idle for a few minutes to allow the turbo to cool down prior to shutting the engine off. Some folks with high performance engines put separate electric oil pumps that run for a few minutes after the engine is shutdown.

 

[WES999]

One reason not to wait too long to change your oil, even if you don't drive the vehicle much:
My Ford ranger that I don't drive that often. developed leak in the oil filter, it had rusted through.
It was only luck that I noticed it leaking, was about a quart or so low.

In my daily drivers I change the oil every 5-6K with a good synthetic. I think some of the manufactures
change intervals are a bit long. The cars with VVT are susceptible to damage from dirty oil.

 

[SpaceBus]

My Ford and a lot of other newer vehicles look at the usage of the car to decide when to change the oil. I have to get an inspection sticker once a year for the car and usually have the oil and filter changed without the code flashing. When I or the shop forgets to reset the code its been about three months before the computer flashes a screen to change the oil. I do a lot of highway miles about 20K a year on long day trips. I work from home so not a lot of local trips and even my local trips allows the car to warm up completely which is key to oil life. I use synthetic so I ma not worried about the oil breaking down. The engine will naturally breathe in humidity just sitting there and that humidity gets in the oil and combustion byproducts that leak past the piston rings can form acids in the oil. If the car is run long enough that humidity gets driven off from the engine and other components. Talk to anyone who does exhaust systems and they sell a lot more exhausts that rotted out to low mileage "granny car" then high mileage cars.

Oil should be changed based on hours of operation modified by number of engine starts and number of times the engine is short cycled where it doesn't get to full temperature . If oil analysis is done the number of hours can be stretched a long time. Industrial air compressors don't have combustion but its a pretty intense application. There are (or were 10 to 15 years ago) that offered lifetime guarantees on their industrial compressors if they were operated with a lifetime lubricant which was a synthetic if the owner sent oil analysis reports on a routine basis and added an additive package on occasion when the analysis indicated it.

By the way oil can really get cooked in turobcharged engines as the center bearing of the turbo can "burn" the oil from the heat on the exhaust side when the engine is shut down. My GMC Syclone required Mobil 1 synthetic oil changes to keep the warranty valid as Mobil 1 had much higher temperature it could withstand before the oil failed. Standard recommendation with turbo engines is let the engine idle for a few minutes to allow the turbo to cool down prior to shutting the engine off. Some folks with high performance engines put separate electric oil pumps that run for a few minutes after the engine is shutdown.

Turbos are hard on cars. The heat thing isn't specific to M1 synthetic. Some racing engines have such tight tolerances they must be fed hot water and oil just to start them. The higher number on the oil weight also determines temperature protection for the oil. Cars that see the track use a 40 - 50 weight oil because it acts like a 20 weight at track temps. Diesel engines run hot so 5W40 is about the standard, but that's also what I used in all of my performance engines and my bikes. Oil made for diesel engines is usually the best oil, so I put Rotella T6 in basically everything, especially turbo engines.

 

[KJamesJR]

Turbos are hard on cars. The heat thing isn't specific to M1 synthetic. Some racing engines have such tight tolerances they must be fed hot water and oil just to start them. The higher number on the oil weight also determines temperature protection for the oil. Cars that see the track use a 40 - 50 weight oil because it acts like a 20 weight at track temps. Diesel engines run hot so 5W40 is about the standard, but that's also what I used in all of my performance engines and my bikes. Oil made for diesel engines is usually the best oil, so I put Rotella T6 in basically everything, especially turbo engines.

+1 For Rotella T6

 

[Ashful]

Which is why you should drive it the 5k-10k miles before the years spent or you’re not getting your money’s worth.

I understand your reason for saying this, but I’m not really worried about getting my money’s worth, it’s not expensive enough to even give a second thought. I change both of my vehicles twice per year, because one of my vehicles actually specified that, I probably have 2000 miles on the one and 2500 miles on the other. I change my wife’s 3x per year, right around the specified 7500 miles.

I find Amazon’s Subscribe and Save is a great tool for this, and anything else you need to remember to do x times per year, like electric toothbrush heads. The oil filters are scheduled to show up on my prescribed schedule. When they arrive, I swing by Walmart for some oil, and do the deed.