Can I trust the oil monitor in my car?

July 10, 2020 7:57 AM

I bought a 2016 Honda Fit last October and have yet to change the oil--I typically drive once a week and have put less than a thousand miles on the car. I'd say the majority of that mileage is highway driving as I don't drive much locally. My oil life estimate is 90%. This makes me nervous. I know I can just go change the oil, but do I need to?

Everything I've found online assumes more typical American driving habits on the range of 5000-10,000 miles per year, and almost every day, which I do not do and probably never will.

posted by Automocar to Travel & Transportation (16 answers total)

I had a 2015 Honda Fit and always went by that monitor for oil changes. When it gets low enough it will pop up a maintenance reminder.
posted by mkb at 8:01 AM on July 10, 2020 [1 favorite]

Just make sure to start up and run the car for a few minutes every week to keep the engine lubricated (the oil drains back to its reservoir after being idle for a while) and you should be fine for some time. Also make sure to check your oil level regularly and top it off as needed.
Also, it's a pain in the ass, but you can always change the oil yourself. Difficulty level: about the same as a tire change.
posted by sexyrobot at 8:12 AM on July 10, 2020

Best answer: You can use science to answer the question rather than guesswork. Send an oil sample to one of the oil analysis services (I have used Blackstone labs in the past and they can tell you what shape your oil is in. This way, you can make an informed decision whether you're stretching your oil too long or not. (they check for excessive wear metals, water contamination due to condensation, etc.) It costs something like $40. I think they also have a kit where you can draw a sample out through the dipstick tube if you're not comfortable with draining oil out of the crankcase.
posted by Larry David Syndrome at 8:28 AM on July 10, 2020

Best answer: 2013 Honda Fit here, largely a weekend driver only. Official word is that I don't *need* to change the oil until it gets to 15%. I will get email reminders at the one-year mark and I do it then, even if it's still around 50%.

No problems yet (at least, not related to not changing the oil often enough). I'd say you're good for a while.
posted by Capt. Renault at 8:51 AM on July 10, 2020

I have had cars for 20 years with oil monitors (including a Honda currently, but different makes) and I've never had any oil-related problems following their schedule. I usually don't change until 5%.
posted by The_Vegetables at 8:57 AM on July 10, 2020

Best answer: I also have a car that I don't drive very much, maybe 800-1000 miles per year. I change the oil on that one every 2 years. I have had that car and been doing the same thing with it for 8 years now.
posted by The_Vegetables at 9:02 AM on July 10, 2020

Oil degrades over time and should be changed at least annually regardless of milage. I also have a Honda and put fewer and fewer miles on it - I used to change the oil twice a year because we have a proper winter and drove more than you. The oil life gauge is meant for typical drivers and does not monitor oil level or quality - it's just a guess. My last oil change happened and the oil life thing claimed 85% left.

I have another suggestion - put fuel stabilizer in with every fill up. Most US gas contains ethanol which is fine if used quickly but can cause issues if left to sit in your fuel tank for long periods. There are many kinds of fuel stabilizer - get one with the measuring container built in and use gloves when handling.

For your periodic use I would also suggest switching to synthetic oil.
posted by zenon at 9:08 AM on July 10, 2020 [1 favorite]

I change the oil in my 2009 Honda Fit whenever the oil monitor says to, or once a year, whichever is more frequent.
posted by vitout at 9:09 AM on July 10, 2020

Best answer: It depends on if you're using a "synthetic blend" or "pure synthetic" oil.

Synthetic blends are made mostly from synthesized materials rather than oil pumped out of the ground but do include some of that in the mix. It will break down over time so most oil-change guidelines note both time and mileage. IE: Change your oil every three-months or 3,000 miles. Most people drive often enough that they hit the mileage well before the time so they only bother with the mileage.

Full synthetic oils don't have the same problem and will stay stable and keep their lubricating properties for much much longer.

Engine and materials technology keep on advancing and modern engines are built to very tight tolerances and are much more efficient so they tend to need less lubricating and the oil stays cleaner for longer. It's not unusual for a Honda in particular to call for 15,000 miles between oil changes. That would make me bet on your car having full synthetic oil in it by default but the more important thing is to use a full synthetic going forward. The car's manual might even tell you that.

I used to sell cars for a living but it's been a while since I was in the business so my info might be a little out of date.

I do little enough driving that for my own cars I just change the oil once a year so I have a hard time forgetting to do it.
posted by VTX at 9:49 AM on July 10, 2020

Because the life indicator is computational rather than using any sort of oil sensor they are conservative. It's really unlikely you need to change your oil any sooner than it indicates (especially on your usage, the additional wear that a hypothetical dirty oil would cause when you only run an an engine a 1000 miles a year is completely negligible compared to the expected life of the vehicle).

Personally I'd probably change the oil when I changes the starting battery but I'd know it was for psychological reasons not anything that made maintenance sense.

Using an oil testing service makes sense when an oil change is hundreds of dollars; not when an oil change is approximately the same price.

If you are worried about ethanol it is generally cheaper/easier to buy gasoline without it. Here that is Cheveron super premium and Shell 91 but I understand it is harder in the US. There are web sites that list stations that provide it.
posted by Mitheral at 10:00 AM on July 10, 2020

Best answer: The maintenance reminder in your Fit uses data from your car's computer system on speed, frequency of use, time, etc. You can trust it to tell you when you need an oil change. I have two of these cars, both of which get oil changes once every 2 years or so because our family doesn't drive much (especially now!). We always wait until the oil life reminder comes on, and have never heard reports from the dealer or other techs that we need to do it sooner.
posted by M.C. Lo-Carb! at 10:03 AM on July 10, 2020

To clarify, you use an oil testing service once or twice to get data for what a safe oil change interval is for your specific driving patterns, then you just change the oil at the appropriate frequency going forward. So it's a one or two time expense for peace of mind going forward. The other issue is that it's a good idea to have someone give the car a general look over at periodic intervals and an oil change is a good opportunity for that. How are your tires, how is your trans fluid, your brake fluid, your coolant, how worn are your brake pads, etc.etc. Unless you are monitoring these things yourself, you don't know if you are keeping your car up properly or not and you may not spot an issue in time to prevent damage or an unsafe condition developing.
posted by Larry David Syndrome at 10:32 AM on July 10, 2020

Best answer: Well, you don't know how it was driven before you purchased it, and you don't know what grade of oil is in there. If it were me, I'd probably go ahead and get a really good oil change (from someone I trusted to put in really good oil), then consider waiting before doing it again.
posted by amtho at 11:25 AM on July 10, 2020 [1 favorite]

Best answer: I drive a Honda Fit (though an older one), and I recently had someone changing my oil condescendingly explain that my oil monitor is assuming synthetic oil, so it is useless if you put in conventional oil. While the method of delivery made me... shall we say... disinclined to pay this person money, it's a good point. So, as other said it may be worthwhile to get it changed once to make sure you have synthetic oil and then let the oil minder do its thing.
posted by past unusual at 1:08 PM on July 10, 2020

Best answer: We have a 2010 Fit with 250,000+ miles on it. It’s my wife’s car and she’s always gone by the monitor with no problems whatsoever. There’s no need to spend money on an oil analysis or anything geeky, especially given how few miles you put on it. Just go by what the monitor says, and you’ll be fine.

Do make sure, though, that whoever does the oil change remembers to reset the monitor. Instructions are in your owner’s manual.
posted by Thorzdad at 2:00 PM on July 10, 2020

Best answer: The majority of problems that come from not changing oil in cars that are driven very rarely, come from moisture condensing due to short trips. But if you are taking it up to highway speeds then this is probably not a problem.
posted by 445supermag at 3:31 PM on July 10, 2020