Piston Slap: CYA Car Care?

Sajeev Mehta
by Sajeev Mehta
piston slap cya car care

TTAC commentator Arthur Dailey writes:


I take our two out-of-warranty vehicles to a local independent garage for maintenance. The owner is 100-percent honest and that is the most important thing. No unrequired work or surprises. He brings out all the replaced parts, the containers and bills for the replacements. He is not the least expensive, but he’s certainly less costly than any of the local dealers.

I have one vehicle, bought new, that’s had all work performed according to the manufacturer’s schedule. However, when I bring it in now, the conversation may go like this:

Me: “The book says that the coolant should be flushed and replaced.”

Mechanic (later that day): “I checked the coolant and it would be a waste to change it now.”

Our other vehicle is lightly driven and not regularly maintained. With that vehicle, the conversation may go like this:

Me: “I think we need to flush and replace the transmission fluid.”

Mechanic: “No. I don’t recommend that. That may stir up too much sludge and cause problems. I’ll just check it and add any if needed.”

As stated, I absolutely trust his honesty. However, while watching out for my pocketbook in the short-term, could this result in some long-term issues?

Sajeev answers:

A manufacturer’s service schedule likely has a metric ton of CYA car care for the uber-diverse driving habits its products experience, and the uber-expensive lawsuits that come with them!

Therefore, don’t change the coolant if the independent mechanic says it’s fine. He will happily earn your business when needed, as he’s earned your trust.

In this theoretical situation where I know nothing about your vehicles’ age/mileage/make/model, your local wrench would likely love to [s]fix your car[/s] get paid, but is more interested in keeping you around. The last sentence drives the point home.

“while watching out for my pocketbook in the short-term, could this result in some long-term issues?”

Your local wrench says the same thing every time a customer (that can be convinced otherwise) wants over-aggressive fluid services for no good reason. He wonders what will happen if another wrench calls him out on his “fleecing,” convinces the owner they were duped, and then loses a customer for life. That same customer maybe, just maybe, is about to have a big-dollar item needing service (bent suspension from potholes, transmission rebuild, heater core replacement, etc) and that mechanic is gonna miss out on the payday.

You “absolutely trust his honesty,” therefore run with that. I do the same with my trusted local independent wrench: even when they get it wrong, they own up to it and fix it. You can’t ask for anything more, son!

[Image: Shutterstock user ibreakstock]

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.

Join the conversation
3 of 27 comments
  • Truckducken Truckducken on Apr 21, 2016

    About the usual density-based coolant testing: it does a great job of telling you whether the coolant will cool the car per manufacturer spec. However, it doesn't tell you jack about whether the corrosion inhibitor package in the coolant is still functional. Change your coolant per manufacturer recommendation, or watch your heat transfer ability, and perchance your radiator, water pump seal, and other components, slowly fade away. Folks following the situation in Flint might understand.

    • Nickoo Nickoo on Apr 21, 2016

      Yep. If you use a commercial coolant, they have additive packs you can drop in every so often. Probably a good option for the lazy.

  • NeilM NeilM on Apr 22, 2016

    "A manufacturer’s service schedule likely has a metric ton of CYA car care for the uber-diverse driving habits its products experience, and the uber-expensive lawsuits that come with them!" Unless, of course, the recommended fluid changes fall within the free service period that some manufacturers include. In those cases all the fluids become 'lifetime fill" except for engine oil, which supposedly lasts for 15K miles. Strangely enough, all these fluids are then recommended for frequent changes as soon as the free service period is over. Go figure.

  • Lou_BC You'd think cops would have an understanding of the laws they are supposed to enforce.
  • Merlyn I’m on my second Spark and love it! I can pass any car I’ve never had a problem going up a hill it does just fine. As for cargo I can fit three suitcases, two book bags and still have the front seat for a passenger. Not sure what point this guy is trying to make. I have hand free phone service and Sirius radio plug in my phone and have navigation. I would buy another spark in a heartbeat.
  • Buickman I won't own one and I'll be happy!
  • Jeanbaptiste Ever since y’all started sending your damn geese down here we’re just been waiting for one of you to show up.
  • 3SpeedAutomatic Drove a rental Cherokee for several days at the beginning of this year. Since the inventory of rental cars is still low, this was a 2020 model with 48k miles and V6. Ran fine, no gremlins, graphics display was easy to work, plenty of power, & very comfortable. Someone must of disarmed the lane assistance feature for the steering wheel never shook (YES!!!!!!!!). However, this woman's voice kept nagging me about the speed limit (what's new!?!?!?!).I was impressed enough to consider this a prime candidate to replace my 11 yr old Ford Escape. Might get a good deal with the close out of the model. Time will tell. 🚗🚗🚗