Piston Slap: Oil Burning and Carbon Cleaning?

Sajeev Mehta
by Sajeev Mehta

Arley writes:

Sajeev,

I have a 2003 Jetta TDI with 178k miles. Runs 100%. My mechanic recommends a carbon cleaning. What are the positives and negatives? To be more succinct, what can go wrong?

You can tune a piano but you can’t tuna fish. (Good to know! – SM)

Sajeev answers:

Conventional wisdom (for both diesel and gas engines) is carbon buildup occurs more often when the owner subjects the engine to excessive idling and a severe lack of full throttle acceleration. Today’s direct injected, EGR equipped diesels (and direct injected gas engines lacking a piggyback port-EFI setup a la Toyota V6s) are sensitive to carbon buildup due to idle time, EGR design and cooling system inadequacies, and perhaps even fuel (i.e. varying quality of bio diesel). Don’t take my word, this company’s blog did a good job assessing the problem.

Whew!

So carbon cleaning is commonplace and a good idea. And be it a seafoam-alike treatment or physical removal/cleaning of critical parts, there’s no downside if performed with even a modicum of care.

Question is, do YOU have a problem?

Considering your mileage (less idling and more highway driving?) and engine performance: probably not. Watch this video (go to 1:39) and DIY if you are even the least bit handy. From the video, make a trip to the parts store for vacuum lines too!

Or just do nothing aside from performing an Italian Tune-Up. That’d work for sure, and it’s totally fun.

[Image: Shutterstock user sasha2109]

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.


Sajeev Mehta
Sajeev Mehta

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  • 415s30 415s30 on Jun 17, 2015

    One of the first things I did when I bought my W123 was cap off the EGR. Diesels are exempt.

  • TammyRice39 TammyRice39 on Mar 13, 2019

    Engine Carbon is headache for me, but you clear my thought regarding Carbon. thanks for the information. bets of luck for future.

  • Luke42 When will they release a Gladiator 4xe?I don’t care what color it is, but I do care about being able to plug it in.
  • Bd2 As I have posited here numerous times; the Hyundai Pony Coupe of 1974 was the most influential sports and, later on, supercar template. This Toyota is a prime example of Hyundai's primal influence upon the design industry. Just look at the years, 1976 > 1974, so the numbers bear Hyundai out and this Toyota is the copy.
  • MaintenanceCosts Two of my four cars currently have tires that have remaining tread life but 2017 date codes. Time for a tire-stravaganza pretty soon.
  • Lorenzo I'd actually buy another Ford, if they'd bring back the butternut-squash color. Well, they actually called it sea foam green, but some cars had more green than others, and my 1968 Mercury Montego MX was one of the more-yellow, less-green models. The police always wrote 'yellow' on the ticket.
  • ToolGuy Some of my first cars were die-cast from pot-metal in 2 pieces: body-in-white plus chassis. I spray-painted some of them, the masking was a pain. The tires did burn realistically.
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