Piston Slap: Always Trust, But Verify

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.

Send your queries to sajeev@thetruthaboutcars.com . Spare no details and ask for a speedy resolution if you’re in a hurry.