Mobil 1: "Ask The Pro" Response... "Why You Should Change Your Engine Oil Annually"

[Bruce H.]

Mobil 1 is a Viper Club Of Ontario sponsor, and supporter of Viper Nation through the Mobil 1: "Ask The Pro" initiative. Please submit your lubricant questions to Bruce at [email protected] and we'll get them answered, like this one....

"Why You Should Change Your Engine Oil Annually—even if You Drive Just a Few Kilometers

David Swain – Mobil 1 Grassroots Motorsports Coordinator - Canada



For vehicles that are driven only a few miles in the summer and stored through the winter, changing the engine oil on a regular time interval—usually at least once per year—is just as important as reaching a certain mileage threshold. This approach keeps the engine protected from the harmful effects of oil degradation and contamination, especially during long periods of storage when used oil can contribute to corrosion and internal buildup.

Why Used Oil Is Harmful

Used engine oil gradually accumulates moisture, acids, unburnt fuel, and metallic wear particles during operation. Even if few miles are driven, these contaminants do not disappear and can cause:

Increased internal engine corrosion, especially when the car is not started for months (such as winter storage).

Buildup of sludge and varnish, which can degrade oil flow and protection.

Potential increased wear on engine components, since degraded oil loses its ability to properly lubricate and protect metals.

Leaving used oil in the crankcase over winter gives these contaminants time to cause damage, subtly reducing engine longevity.

Time vs. Mileage: Why Time Matters

Synthetic motor oils like Mobil 1 resist breakdown better than conventional oils, but time-based changes are still recommended. Oil degrades chemically with exposure to air, temperature changes, and moisture, even if the vehicle is not being actively driven. Most experts and oil manufacturers—including Mobil—recommend changing the oil at least once per year regardless of mileage for cars that see infrequent or seasonal use.

A fresh oil change before storage removes acids and contaminants, ensuring only clean oil is in contact with engine parts all winter. This is especially pertinent with synthetic oils like Mobil 1, which maintain protection qualities longer but are not immune to the effects of age and moisture.



Mobil 1 Oil Recommendations

Mobil 1 and other premium full synthetics are formulated for extended service life and offer better protection against breakdown, but Mobil recommends following the owner's manual—typically a 1-year or mileage-based (usually 12,000-16,000 kilometers) schedule, whichever comes first, for vehicles in low-mileage and storage situations.

Practical Tips for Seasonal Cars

Change oil and filter before putting the car into long-term storage for the winter.

Do NOT run your vehicle while it is in storage. You will cause more harm than good.

Use high-quality synthetic oil like Mobil 1 for added protection, especially during extended periods without engine operation.

Even if only several hundred miles are driven in the summer, use the annual change interval as your baseline.

Always check for the specific recommendation in the vehicle’s owner's manual.

For a well-protected engine, change the oil every year before winter storage—even on cars with very low annual mileage. Clean oil, such as Mobil 1, ensures contaminants aren’t left inside your engine when it needs protection the most."

 

[Badinternet]

2x per yr is better

 

[Bonkers]

Ive been saying this for at least two decades here. Oil weight
is kind of important, Oil brand (as long as its not a shit brand
like amsoil) is kind of important. What is really important is the
use of a Viper Oil Filter and that you change it every six months
or 5,000 miles.

I dont think David is wrong by any means, but you are caring
for a Viper, not a Volvo... if an extra $100 a year is too much
effort to take care of your baby, then maybe the car hobby aint
for you.

 

[Bruce H.]

Right on, Bonkers.

David plans to write more articles geared to the Viper community, and we've discussed some of those upcoming topics. It's a confusing topic with so many brands and grades of oil, conflicting recommendations, and so much misinformation out there, but there's also a whole lot of science to separate fact from fiction. We're fortunate to have Mobil 1 and David as a resource.

There are a number of important factors that can affect an owner's oil change strategy, including type of use, environment and engine condition. And knowing what those key factors are will make a real difference down the road to the health of the engine, and potentially save a lot of money in repairs.

 

[MoparMap]

So I think there's a bit of a chicken and egg problem with the winter storage thing. By the letter, it sounds like you should change the oil before storage, but not run the car. But, if you don't run the car, you're not going to get the oil where it needs to be to cling to parts during storage. So I'm guessing one good start up to temp after the change and before storage would make the most sense, but I'm not sure how that differs that much from the "couple hundred miles of driving in summer".

 

[GTS Dean]

Short trips and heavy loads when not fully warmed up are what's worst for engine oil. If the engine doesn't get the fan cycling regularly with water temps above 212F, your water condensate will acidify and sludge deposits begin to form. If you run too cool a t-stat, you may not get the crankcase hot enough to boil the moisture off - even on long trips. I've done regular highway commutes in my '14 and '18 RAM Hemis over an hour each way. I noticed the ECU controls the fan so the oil temp cycles a little above 212F for a few minutes, then back down to about 208F for longer stretches. I do changes at 10k miles.

If you're going to track the car, watch your oil pressure and make sure your sump doesn't drop more than a quart without makeup. It takes time for the top-end oil to drain back to the sump, so combined periods of high rpm/high-G loads can starve the bottom end, cook the oil on the bearings and lead to high friction levels.

I've tracked my car for 29 years since new - mostly with Mobil-1 15W-50. I sample it regularly with annual, or longer change intervals. I will grab a hot sample mid-year just to see how things are looking inside. Even with the 8qt OE pan (and IPSCO baffles) I ran it 36k miles and never had rod bearing issues. I did a rebuild 5 years ago and went to the 10qt pan with baffles because it was available. Keep a file of your oil samples and build a spreadsheet to monitor individual results over time.

 

[Bruce H.]

So I think there's a bit of a chicken and egg problem with the winter storage thing. By the letter, it sounds like you should change the oil before storage, but not run the car. But, if you don't run the car, you're not going to get the oil where it needs to be to cling to parts during storage. So I'm guessing one good start up to temp after the change and before storage would make the most sense.

Yes, start the engine after the oil change for the noted purpose... "ensuring only clean oil is in contact with engine parts all winter."

As far as "I'm not sure how that differs that much from the couple hundred miles of driving in summer"...

Changing before storage is really about making an effort to minimize the accumulation of contaminents, and shortening the period of time you leave them in the engine to do damage. Those with next to no miles since their last oil change will use their own judgement, and I bet there are many that haven't had an oil change in years due to low miles unfortunately!

 

[Bonkers]

So I think there's a bit of a chicken and egg problem with the winter storage thing.

Also depends on youre definition of "winter storage."

If youre like me where "Winter" is defined by first salt drop to
first spring washout then youre only talking 2-4 months at most.
A fresh change before will be fine (especially if you do an
occasional temp-up in between, but it HAS to be a full temp-up,
anything less than 212d will not burn the moisture/acids out.)

If your like one of the guys out here who mothballs the car from
Sept-May, then it would be best to change the oil (not necessarily
the filter, but... again... $20) parking AND reviving. Sitting oil
collects moisture and acid - neither of which you want running
through your motor.

 

[serafins]

I have a '94 ski boat with a '94 Corvette LT1 engine in it. it's basically an aluminum head 350 chevy 4 bolt main. It routinely runs 4-5k rpm for 30 minutes at a time, then gets shut down, then started right back up and doing it again. The boat has 2500 hours on the original engine with no rebuild. That is unheard of for a boat.That's like 300k miles on the engine in a car. I've never changed oil before winter storage. Never fogged it either. I pour good antifreeze in the block to winterize it and put stabil in the tank and run it for a few minutes to cycle it through. I've owned it fourteen years now. It has the exact same oil pressure as it did when I first bought it. 40lbs at idle, 80lbs at cruising speed. That engine specs 20w50 and I run Valvoline VR1. I just took a valve cover off this spring to inspect it and it looks brand new underneath.

The crank in that engine sits partially in the oil. My understanding is the crank is well above the oil level in our cars. So I think you're even at a lower risk for corrosion issues due to contaminants in the oil.

Now you absolutely do need to change it before spring startup. Oil gets a ton of water in it from condensation. Not so much on aluminum block cars from my experience but still. You don't want to send a shot of water through your engine on the first startup because it will find the lowest spot in the pan.

Another big thing as some have mentioned is don't start it up just to idle it! the oil will not get up to temp to burn off the condensation it has accumulated and you are just cycling water through your engine by doing this.

Now, what I do think is a concern for those with unrebuilt engines is seal leakage. I don't have to worry about this on my boat with the thick conventional 20w50. But for my viper, I do plan to change the oil before winter with conventional high mileage oil. Just to get it on the seals and rubbers so it can soak in over winter. Then before running it in the spring, I'll go back to Mobil Euro 5w40 full synthetic or 5w50

 

[doctormosfet]

Ok, so change the oil (and filter) before winter storage and it seems like I should also change oil again when taking out of winter storage. Fair enough. However, when taking out of winter storage, is it really necessary to change the filter as well? If the engine is not running through the winter, then there is no oil circulating through the filter and so it is arguably not undergoing any degradation. Maybe take it off to drain any oil that's in that region and then re-install it as it essentially has zero miles on it?

I understand some may argue that spending another $20-30 is worth it for the assurance of protecting the engine, but I'm trying to really think through a good reason for it. I'm finding that OEM Viper filters are not as easy to come by as your typical filter and I don't see a reason to be cavalier or wasteful with a high quality filter which may otherwise be perfectly operable. Any thoughts?

 

[Bruce H.]

Ok, so change the oil (and filter) before winter storage and it seems like I should also change oil again when taking out of winter storage. Fair enough. However, when taking out of winter storage, is it really necessary to change the filter as well? If the engine is not running through the winter, then there is no oil circulating through the filter and so it is arguably not undergoing any degradation. Maybe take it off to drain any oil that's in that region and then re-install it as it essentially has zero miles on it?

I understand some may argue that spending another $20-30 is worth it for the assurance of protecting the engine, but I'm trying to really think through a good reason for it. I'm finding that OEM Viper filters are not as easy to come by as your typical filter and I don't see a reason to be cavalier or wasteful with a high quality filter which may otherwise be perfectly operable. Any thoughts?

Changing the oil and filter is recommended before winter storage. Doing another in the spring is a waste and completely unnecessary. Any condensation from storage will burn off quickly without hurting the engine.

 

[Bonkers]

is it really necessary to change the filter as well?

Id argue on the "completely unnecessary" point, but i see
no reason to swap out the filter in the spring. If money is
that tight for you, you could also just put a $4 fram on in
the fall with cheap HM Mobil1, and do a proper oil change
in spring (before you start driving it.) For storage, the
filter is merely a plug to hold the oil in, its not doing
anything else for those months.... assuming you are not
starting it periodically during the winter as well.

Connect yourself with Tator, JonB, Sawyer, or Andy Savakinas.
They are part of the Viper Vendor group and any one of
them can source you an OEM Filter for a reasonable price.
During production Amazon is still currently the best place
to source filters... but... my experiences with other car club
is showing alot of counterfeit car parts coming from that
site so buyer beware.

 

[doctormosfet]

Well I'm not worried about the financial cost. It just seems wasteful to change the oil twice. Yes, Vipers are thirsty machines, but if one change pre-winter and a condensation burn/boil-off works just as well, then there's just no need to be wasteful.

 

[Bonkers]

there's just no need to be wasteful.

I completely understand, but there is a thought process
that "wasting" 7qts of oil to keep an 8ltr motor running
efficiently is a net gain in the end. Especially if you properly
recycle said oil.

And dont forget, its not only about condensation - metal
produces acid when wet (either by oil or water) and the
corrosion developed by that acid is just as bad, if not worse
than the rust caused by condensation. If stall oil were a
stable fluid, the notion of 3 MONTHS / 3,000 Miles would
never have developed. I would be simply every 3,000 miles.
(Editors note - this is also why some of these "500 Mile"
Collector Vipers are so scary, there is a real chance they have
20+ year oil, gas, brake fluid still sitting in them...)

If it makes you feel any better, according to my data logs,
as of January ive used ~523 quarts of oil just in my cars,
not to mention 30,428 gallons of gas, so i alone will absolve
you of any Carbon Footprint Guilt you could possibly have
over it... ;-)

 

[Goggles Pizano]

You should be more worried about ethanol based fuel sitting and not fully being used more then the oil.

 

[GTS Dean]

The 3/3000 adage is from the "Mr. Dirt" commercials. I think that ad campaign was from the late '70s/early '80s. To a large degree, it is completely absurd with today's highly refined engine oils and additive packages - particularly with respect to full synthetics.

For a historical perspective, that's also about the time that widespread use of turbochargers and Mobil1 appeared on the market. I recall they were touting extended drain life of 20-30,000 miles under mostly highway use. They also used the side-by-side frying pans on a stove top to show how stable it was at high temperatures relative to conventional oil.

You can believe what/who you want to believe and I'll keep doing what I've been doing.

 

[doctormosfet]

I completely understand, but there is a thought process
that "wasting" 7qts of oil to keep an 8ltr motor running
efficiently is a net gain in the end. Especially if you properly
recycle said oil.

And dont forget, its not only about condensation - metal
produces acid when wet (either by oil or water) and the
corrosion developed by that acid is just as bad, if not worse
than the rust caused by condensation. If stall oil were a
stable fluid, the notion of 3 MONTHS / 3,000 Miles would
never have developed. I would be simply every 3,000 miles.
(Editors note - this is also why some of these "500 Mile"
Collector Vipers are so scary, there is a real chance they have
20+ year oil, gas, brake fluid still sitting in them...)

If it makes you feel any better, according to my data logs,
as of January ive used ~523 quarts of oil just in my cars,
not to mention 30,428 gallons of gas, so i alone will absolve
you of any Carbon Footprint Guilt you could possibly have
over it... ;-)

Wow...looks like someone needs to install a gas station at their house For sure, if I were worried about carbon footprint, I would not have purchased a Viper...

I get the point that having the freshest oil in the car during spring startup is technically the best way to go. That makes sense. I suppose the question is, how much does the oil really degrade while in storage, how much moisture and acid actually build up, and what impact it actually has. Hard to know for sure without accurate measurements and, to be fair, it likely depends on environmental factors such as garage temperature, humidity, etc., as well as how hard you drive it while in use. So, if you think you can get away with it (and maybe in many cases it's fine), then just stick with the pre-winter oil/filter change with a spring burn-off. If you want to play it safe, then change the oil again in the spring.

FWIW, I end up getting oil changes in my Lexus IS350 about once per year, using synthetic oil. It has 175k miles on it and is still running strong.

 

[yzf1999]

I’m changing the oil and filter once a year at the beginning of November when I put her to bed in my heated garage until May 1st. I will not start the car during that time. I’ve only put 750 miles on it this summer and that will be about what I put on it each year. I’m not going to over think this oil change thing.

 

[Bruce H.]

If anyone has any questions about this be sure to let me know. Our "Mobil 1:Ask the Pro" sponsor will be attending our club's End-Of-Season event on Nov. 22nd and he'll be happy to be grilled!