Sitting in my dealer's waiting room, came in for a 30000 mile service. Just talked with the service manager. I asked for service 'by the book' meaning my owner's manual. got 'sold' a top end de-carbonizing service, some kind of hybrid coolant thing, and who knows what else. After explaining to the service manager just what I meant by 'by the book', he told me about a program Toyota offers to dealers, that includes the decarbonizing service. And that the menu system in their computers causes problems because it includes things not in the manual. Further, that Toyota service menus are being changed to be in sync with the owner's manual, and that de-carbonizing would be offered only if it appeared needed upon inspection. I thanked him, and explained that if I was sold something I did not want and did not find in my manual one more time, that would be the last time the dealership saw me. Is he putting me on, or is he just handling a complaint?
Decarbonizing? With unleaded fuel I think the carbon thing is no longer valid. This falls in line with the "Toyota Care" scam. For a Prius TCare amounts to 2 oil changes, maybe a cabin filter and a bunch of inspecting.
If you haven't noticed any problem and the dealer cannot show you trouble codes then this is almost certainly a boat payment for the dealer. Today's oxygenated gasolines (for example E10, containing 10% ethanol) prevent carbon buildup. Dig out your copy of Toyota's Scheduled Maintenance Guide, open it to the correct months/miles page, hand it to the service writer and say "do this". As 2k1 implies below, if you tell a dealer to do anything "by the book" they'll use *their* book, not Toyota's. If you don't have the SMG see here: Toyota Parts and Service
+1 on both of the above. The dealership is trying to fool you. Never tell them to do things by the book. Tell them to do what the book says explicitly. Practice: "I need an oil change and a tire rotation, that's all please".
Decarbon was a add on, however still a valid one. You would be supprised the level off carbon stand off in the inlet track. Had a clogged injector yet? the inverter coolant ? couldnt tell you what the book calls for on a USDM spec vehicle.
Yes I agree if your talking about a throttle body clean as opposed to a "top end de-carbonizing" treatment. Top end to me refers to cylinder/valve area and the only way to check that is to pull a plug. Then the only treatment I have heard to de-carbonize the cyl area is using seafoam which is sketchy. I wonder if they explained in detail what they would do for that because if it is a throttle body clean thats not a bad idea as you suggest. The throttle bodies get pretty sooty quick on our cars. I did mine first at 15K and it was pretty bad. In fact after a thorough clean I could see the soot was starting to attack the brass tb butterfly as it was pitted a little. Important to keep that area clean as the throttle body on a Prius is about $1500 installed. But I bet to the dealer "de-carbonizing" is just a ridiculously over priced can of STP Fuel Treatment. Or maybe Seafoam. What with all the other crap they told the op.
The reason cleaning the throttle body is required on "traditional" engines is because of build up from the EGR. I usually remove and clean the unit on traditional cars at 50K. edthefox5 reporting the same type build up on his Prius at 15K suggests I take a look since it's over 20K now.
Top-end decarb involves an in-tank cleaner and a seafoam-type product that is injected through the vacuum lines or throttle body. It is effective but is an optional service unless you are experiencing problems. I too, have noticed that dealers are now making their 30k services identical to what's called for in the book. Unfortunately this means they are doing fewer services but charging the same $300 they used to!
BG makes many wallet-flushing type products, including one (Induction System Cleaner) that could be described as a de-carbonizer. But this is just another form of a (99.9% of the time) needless fuel injector cleaning.
I have seen a Seafoam type treatment improve drivability on older cars. On cars susceptible to carbon buildup (some higher performance engines), this may also be a worthwhile service periodically. But not on our cars, as we don't have those problems except for a dirty throttle body.
