By on March 5, 2012


Patrick writes:

Okay, I have a question. Strictly follow the manufacturer’s suggested maintenance schedule, or only perform demand maintenance?

Of course I love buying cars where the previous owners were diligent and could prove it. I do a hybrid, I change fluids regularly but do the rest as demand (with exceptions.) Timing belts on interference engines an example of an exception.

Sajeev answers:

As much as I’d like to say you always–without question–follow the owner’s manual, Toyota and VW/Audi ruined that delusional notion with their engine sludging problems a few years back. It doesn’t matter if its your significant other, ex-significant other, someone you wish was your significant other, mother, co-workers, best friend, or the dude that bags up your grocery: always trust, but verify.

The people behind the words in your owner’s manual have the best intentions, but nobody knows how every subsystem in every powertrain fares after 3-10 years of use.  It’s completely impossible to know without never-happening powertrain changes (i.e. Panther Love) so I shall say it again: always trust, but verify.

So let’s pretend that you, dear reader, actually give a crap about your ride. But you don’t have the time/money/interest to ship fluid samples off to see when exactly your oil, coolant or brake fluid isn’t 100% functional. So perhaps you should flush out the brake system on every 2nd brake job, just because you live in an area of high humidity and you feel the pedal in your car is too spongy. I mean, the mechanic is already working in front of every bleeder valve: why not spend a few more bucks for another bottle of brake fluid? Or change transmission fluid annually because you tow a lot of heavy things in your line of work. Sounds fair.

I often do an oil change when it smells a little smoky and has 8-10,000 miles on it. Or just do whatever the dash light says, as it considers your driving habits.  I have yet to hear that a maintenance minder came on when it was too late: they err on being conservative.

Your “Hybrid” notion can be a good choice, as long as it doesn’t justify something ludicrous like the 3000-mile oil change on damn near any car running modern oil.

Bonus! A Piston Slap Nugget of Wisdom:

Perhaps “trust but verify” is a dark way to live your life. But maybe it’s the best way to believe in yourself, making yourself accountable for the actions around you. Because we do have control over many aspects of our lives, whether we choose to exercise control is always a delicate balancing act of time/money/interest.

Example: I recently spent a ton of bread getting the Terrazzo floors in my new home wet sanded, chemically cleaned and then epoxy-coated like a race garage.  Turns out they couldn’t get the stains out, for a fairly good reason. Instead of getting pissy and demanding a lower price, I paid them and was on my merry way. I had no interest in fighting that battle. But I did trust them, and they let me down. I had no way to verify their process/conclusion at the time, so I gave up. I got bigger fish to fry.

And perhaps you do too.  So maybe you should just read the manual and listen to your dashboard.


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36 Comments on “Piston Slap: Always Trust, But Verify...”

  • avatar

    Being overly meticulous (anal) is not necessarily a good thing, but the other extreme will cost you even more, so find the middle ground and be diligent – neither neglecting your means of transportation or put it on a pedestal.

    We follow pretty much the owner’s manual for our cars, but instead of changing oil every 3,000 miles or 3 months, I change oil every four months. I can live with that.

    As a result, our cars have done very well, but then again, we aren’t young and I’m finding out firsthand that older people’s cars last longer! Phooey…

    As far as mottos go, our motto in the 9 Strategic Reconnaissance Wing in the air force was: “In God we trust; all others we monitor”!

  • avatar

    So I’m totally a 7500 mile person. I do a highway speed commute of about 80 miles/day, and have had no problems with my engines following that schedule, and i tend to prefer synthetic which seems to let me stretch to 10k if I wanted. That’s about every 3-5 months depending how many miles I drive between changes.

  • avatar
    Jeff Waingrow


    As you know, some manufacturers provide “free” maintenance for what is typically the warranty period. I’ve always wondered whether they don’t have an incentive to offer the very least possible in order to save money. If that causes problems in the future, the problems are not theirs, and they may even get the opportunity to profit from eventual repairs. Or is that too cynical?

    • 0 avatar

      If I recall correctly, the “type” of people who were leasing BMWs prior to their free maintenance program, would do absolutely zero maintenance on their vehicle during the leased period. And this was impacting the either the re-saleability of BMWs or their CPO program.

      Yes, there are these types of dirtbags out there. And 9 out of 10 bimmer drivers I pass by in Seattle are exactly this. Then again, most people I drive by in seattle are d-bags anyways.

      • 0 avatar

        “If I recall correctly, the “type” of people who were leasing BMWs prior to their free maintenance program, would do absolutely zero maintenance on their vehicle during the leased period.”

        That you are to perform all factory recommended maintenance is spelled out in the lease contract.

      • 0 avatar

        I can’t speak for BMW, but when we returned my wife’s leased VW they did noting to verify that any routine maintenance had been done. I had the paperwork showing that the last couple of oil changes had been done by an independent mechanic, but they did not ask for it.

        Interesting that the VW service department insisted on using synthetic oil for scheduled services (I asked them to show me where the manufacturer required it in the 2.5, they could not, so I politely declined), but when the lease was up VW did not really care about oil changes at all.

        Definitely soured me on buying a used (or CPO) car, at least from VW.

    • 0 avatar

      Jeff: because of the limited service points in modern cars (EFI,non-serviceable ball joints etc) I doubt there’s much cynicism needed here. The only thing BMW doesn’t provide are new tires, which is what they really need to do considering what’s left of the average BMW donut at the end of a 4 year lease.

  • avatar

    Brake fluid should be changed at least every 3 year years regardless of miles because it is hygroscopic. It will absorb water even through the walls of rubber brake lines.

  • avatar

    The military and many airlines have learned the hard way that it is better, and safer, to replace items “on condition” than at a set schedule. There are exceptions, but overall its not only cheaper, but safer in the long run. Things are actually more likely to go wrong right after someone has replaced something.

    I do not wait 90,000 miles an cough up $900 to replace a timing belt(several quotes from different shops for the Camry), I INSPECT IT at shorter intervals, such as 30,000 and replace as necessary.

    People get hung up on engine oil changes as the ONLY important maintenance item and tend to ignore the rest. That is because oil changes are easy to do and shops constantly sell them. Even without used oil analysis, 3mo/3000mi is absurd under most any imaginable use of a passenger car or light truck. In this case, follow the owners manual is the best advice. Toyota did go way overboard in response to a sludge issue with one engine family by reducing the interval from 7500 to 5000 miles across the board, even as oil quality has increased. I go by the on-board monitor with the Honda.

    • 0 avatar

      The 3000 mile oil change interval is based on providing a reasonable vehicle lifetime to someone who never opens the hood of the car, not how long properly topped-off oil will last. Even a car that uses some oil won’t get low enough to hurt the engine in 3000 miles.

      My wife’s Subaru is a worst-case scenario of all city driving and a small crankcase. I stick with Subaru’s 3750 mile recommendation for severe service, even if it is a bit cautious.

    • 0 avatar

      I do also. My Fit calls for oil changes about every 10,000 miles.

  • avatar

    I’ve had a couple of Hondas and I noticed that the dealer would try to sell me “xx,000” mile maintenance packages that were very overpriced. I would instead ask for the services recommended by the owner’s manual, leaving out the extraneous stuff the dealer threw in to justify their inflated price, like “lube chassis”. Saved thousands over the time I had the first one (I got rid of the second after 2 years).

    There are a lot of dealers out there who will try to sell you stuff you don’t need (ex: fuel injector cleaning for a Toyota Sienna with 40,000 miles).

  • avatar

    I’m still learning the basics of car care and try to pay attention to the little things. My dealer keeps on trying to push the 3,000 mile changes; the manual prescribes 3750 for “severe” service and 7,500 (just best guesses – don’t have the manual on me). I tend to split the difference and go 5,000 to 5,500 since my driving conditions aren’t constant. When they ask me why I didn’t come in I act like I “forgot”, which is what mostly happens to forgetful people; most of the people in my family act like they don’t know that oil is replaceable, or if they do, they just add some oil once in awhile.

    I’m also trying to learn how to do the inspections myself, but since the car is in warranty I take it in and have them do it; I don’t need to void the warranty because I did something dumb. Oil changes at the dealer are on par with the quick lube stations and the indy shops around me. Cheap piece of mind or me being played like a fiddle; I don’t know.

    I’m learning.

  • avatar

    Good advice.

    Regarding the Terrazzo, did you at least scold them for not informing you about the ‘stain’ problem before going ahead with the epoxy finish? After all, it should have been clear from the outset that the removing of such stains was likely one of the primary reasons for doing the refinishing work in the first place. (assuming of course, that this is how it actually happened) To me, that would be like a garage going ahead and remaking a transmission while knowing in advance that it wasn’t actually going to fix the problem it was intended to fix.

  • avatar

    I have a Prius that I bought new just before Christmas, and I do a lot of commuting miles so I’m up to the 5000 mile service already. Now, the Toyotacare plan does not include an oil change at 5000 miles for free, you have to wait until 10,000 – this seems high for a running in period to me, so I have agreed to pay for the oil change myself. Should I bother? Also, to further muddy the water, the car itself gives an “Oil Maintenance Required” message when I turn it on now – why would it say that if Toyota does not recommend it? Yet they won’t pay for it.

    I’m doing 60-70 commuter miles a day, SoCal county roads, no freeway, and I go up and down 3000 feet twice every journey, if it makes any difference.

  • avatar

    It seem like you are spending as much on oil changes in the USA as here in Europe despite the fact that the oil are at least twice as expensive here. I don’t know if anyone changes more frequently here in Europe than every 9400 miles. And I don’t think we have more engine problems than you. However, my Cadillac STS-05’s oil change monitor tells me to change every 12500 miles. But instead of paying someone 600usd to change the oil and filter I do it myself for 100 usd and every 9400miles, better safe than sorrow. Every second year or so new coolant and brake fluid.

  • avatar

    Amazingly my oil change place actually recommends 7,500 mile changes and says to stop by anytime so they can check the level and will top it up for free. This is a Mobil Quick Lube type place, but the owner is actually honest! I’ve had them check fluids before and been told “nope everything looks good, no need to change yet” which is almost never the case at these places. At other locations they want to replace my wiper blades without even LOOKING at them and use scare tactics when you refuse a recommended service (like fuel injector cleaning).

    • 0 avatar

      Mobil 1 full synthetic as well as the Mobile 1 Super 5000/7000 synthetic blends are considered high quality oils that will indeed last this long. The “house brand” dyno oil that’s used at cheap oil change places (think of $18 oil change specials and coupons) is usually of much lower grade. I would not run more than 3000-4000miles on it.

      • 0 avatar

        And you’d still be wrong, unless it’s not API-approved oil which is highly unlikely. There is NO API oil on the market which needs to be changed every 3,000 miles in any car on the road. Period.

  • avatar

    I just had the oil changed with synthetic by an independent specialist. The car has a service computer that requests oil changes at 5,000 mile intervals based on my driving. Today I noticed a sticker in the top corner of the windshield reminding me to change the oil after 3,000 miles or 5/12, whichever come first. 2 months? GMAFB. Considering this is coastal San Diego, where the temperature never reaches 40F on the cold end and 90F on the high end, I think a year would be fine for oil that doesn’t see 3,000(or 5,000) miles. Puts a damper on my faith in this shop.

  • avatar

    I’m still trying to wrap my head around the weird juxtaposition of the Reaganism in the headline and the image of Chairman Mao.

  • avatar

    Doesn’t hurt to check the forums for your car and see what others are doing. I had a weird noise in my Element, did some checking online and found that it was the fluid in the differential. Honda says change at 50K, forums said go 30K, I was at 40K and had been living with the sound for some time. Did my tranny oil at the same time, fluids are cheap.

  • avatar
    Educator(of teachers)Dan

    Oil monitors are a god send if listened to. My school district is on a strict every 3000 miles oil change policy on vehicles without oil monitors but I’ve noticed that the vehicles with oil monitors tend to go around 6,000 miles between changes thereby saving the district quite a bit over the typical 200,000 mile life of one of their vehicles.

    Oil life monitors are likely doing more for the environment than they get credit for.

  • avatar

    I tend to find whenever I try to “fix” things I end up breaking a couple of more things…

    People often think that changing transmission fluid or gearbox oil is a good idea. In my experience, it almost always makes things worse. Just wait until it needs an overhaul or the clutch burns out.

  • avatar
    Robert Schwartz

    Stupid question here. How do I know whether I have an interference engine or not.

    • 0 avatar

      That is a great question! I do not believe there is any way of telling if a certain vehicle has an interference engine simply by poking around under the hood. The best bet would be to do some research online or perhaps call a dealer or manufacturer or maybe check the owners manual. If your car has a timing belt or chain and it is an interference engine and the belt breaks, the engine will become damaged. See this link for more info:

  • avatar

    That’s how…

  • avatar

    Sajeev, Good article… Okay, here is the obvious question: my son’s 2000 BMW 3-series oil light goes on at 14,000 miles (it uses Mobil One synthetic) but the BMW forums suggest changes at between 7,500 to 8,000 miles. Is the BMW light activated by use patterns of the driver? Or does it just go on every 14,000 miles? I mean, I could see going 10,000 miles with synthetic oil– due to its longevity, and the fact that it costs quite a bit more than regular oil… What do you think?

    • 0 avatar

      It is supposed to work on usage. So yeah, its likely that your son’s car is driven in a manner less abuseful to oil. Maybe he lives in an area that isn’t too hot, does lots of highway driving, etc.

      14,000 mile oil changes are entirely believable.

  • avatar

    verify part – tough for my mom’s 2004 325xi – i go to the forums and they seem to be full on people just reciting these ridiculous maintenance lists like replacing the entire cooling system. and the manual just addresses changing the oil when computer says so, which based on the first oil change was a big mistake.

  • avatar

    GM’s Oil Life Monitor is a fantastic idea. I’m getting 15-16000km in the winter, around 18000km summer between oil changes. I use Blackstone for oil analysis and it looks fine at these intervals. I just wish it had a few more on-line monitors.
    Since I run the oil down to less than 5% oil life, but check via oil analysis, I guess I hit the mark for ‘Trust. But Verify.’

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