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Carbon deposits on 4 year old Jetta

Daughter was told that she had major carbon deposits on her valves causing the sputtering during idling. They wish to perform a "power high pressure flush $179.00. I am adding some BK44 instead of taking their “dealership” recommendation. Question: does using lower priced ethanol fuel in a turbo engine cause carbon build up in four years that need their "service center procedure.

What does the owners manual tell you to use in this engine? Rocketman

high octane fuel and she hasn’t been using it all the time

Did the Dealer say they have disassembled engines with the the same mileage and issues as your daughters car and found “major carbon deposits”? I would have kept one of these valves to show people, what procedure are they using to determine the valves have major carbon deposits?

On the other hand the BK44 people also need proof their product works,not testomonials from “satisfied customers”

according to the service manager, they found it when replacing a thermostat within the radiator system

I would like to hear the explanation of that one, Last weeks car talk show had a solution about spraying water into a carburated system to clear carbon deposits, Maybe there is a possibility of doing it on a fuel injected system?

If I read between the lines this was just a standard ploy of typical service department a probable fraud to get more hours for their overpaid mechanics.So just use the appropriate fuel for the remainder of the ownership?

How could you see the base of the intake valve looking through a coolant passage?

I’m inclined to suggest the old-fashioned approach to this:

Take that thing out on the freeway and flog it nice and hard. When you get on the freeway on-ramp, pin the throttle and run it up to 80 or 85. Keep it there and just drive it nice and hard for a few miles, let it get warm. Exit, get back on the freeway going back the other way and do it again.

As you probably conclude I am not a mechanically oriented person, so I have very little auto knowledge to evaluate comments and recommednations from service managers . I just attempt to prevent my daughter from being ripped of since she struggles to make her bills each month, and I am attempting to get her to perfrom more detailed analysis of things especially from vendorsin the service business.

Please don’t take my disbelief of the Service Managers “explaniation” as a criticisim of your judgement. I am aware that you are doing your best in regards to helping your daughter deal with her auto repair decisions.

The bit about carbon deposits causing sputtering is utter BS or a misguided diagnosis from a mechanically illiterate service writer.
NEVER put much faith into what a service writer or manager says; very few have ever been mechanics and most only have a very limited bit of mechanical knowledge if any at all.

Some details on the symptoms would help.
How many miles on the car, any Check Engine Light on, how long since spark plugs, wires, etc.
Does the problem exist all of the time at all RPM ranges?
Does it idle smooth and cut out on acceleration?

The questions are many but the nitpicking details are what it takes to try and provide at least a half-educated guess.

IF it does have carbon deposits on the valves, they would not be likely to cause sputtering at idle. I have seen BG-44K (Is that what you’re referring to?) take care of this sort of thing several times. It’s one of the few “miracles in a can” that really works. On the other hand, if it is just a slightly clogged injector, a can of Sea Foam will clean it up at a far lower cost.

Higher octane fuel burns COOLER than regular. That is probably why the turbo engine needs premium. If the owner’s manual says premium is REQUIRED, use it. If it says it is RECOMMENDED, she’s probably safe using E-10, but not E-85. If it is REQUIRED, and she can’t afford the extra $20 a month for premium, she should get another car.

I would not recommend “blowing the cobwebs out of it” at 85 MPH. IF indeed it has cobwebs, you can acomplish the same thing at 55 MPH and the same RPM in fourth gear.