Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Decarbonization flush

a Decarbonizatin flush was recommended for my 2003 Toyota 4Runner. Is this necessary?

Only if you’re experiencing problems, and only if it’s done by a real mechanic, not a quicky lube place. Who told you you needed it, and why?

The Toyota dealership service dept is recommending it. The 4runner has 100K miles on it but it is running fine. They said that it will decrease carbon monoxide build up thus decrease emissions. It just didn’t sound legitamate to me. Thoughts?

Does it pass emissions tests OK? If so, I’d avoid the flush. I’d also find a good independent mechanic, no need for a dealer.

Yes, it passes the emissions test just fine. Thank you for the advice.

This is a good profit service for the dealer. I have an '01 Sequoia that started stalling when I came to a stop at the end of highway exit ramps. The dealer reported the air filter was dirty and carbon on the intakes. I had the flush done then and the filter and all was fine. A few weeks later I pulled the plugs and they were very worn, so that likely contributed to my problem.

I had purchased the car used a week or two earlier and I got all the maintenance up to date over the next several weeks. This was a year ago and the Sequoia is great. Since you’ve had your car and maintained it all along I’d only go for the flush if you were having some sort of running problem. Toyota’s do get some carbon in the intake and a clean out every 60K miles or so may help, but I’ve heard you can do a decent job of it yourself with a shop vac.

Few cars ever need that service. Why did they say you needed it? My guess is it was a slow week in the service department and they needed a little more work with a good profit potential.

Correct me if I’m wrong, but carbon monoxide is a gas and would not really build up on a surface. I can see reduce carbon monoxide emissions, but not build up.

Carbon build-up is something that only happens to fuel injected vehicles if there is a problem. If you are experiencing problems, and you think this will help, the first step should be to diagnose and fix the problem that is creating the Carbon build-up.

Dealers recommend decarbonization to prevent you from accumulating any excess deposits in your bank account. That’s all it accomplishes.

We did not get the decarb service done as well as bypassing a few others that they recommended that sounded iffy. Thank you for input! :wink:

It sounds like the wallet flush to me. Your milage may vary. The carbon monoxide build up is not right.

One of our vehicles is a 2003 Toyota 4Runner and the owner’s manual says nothing about a decarbonization flush. I have an independent shop that does all my work–they did the 60,000 mile servicing a while back and didn’t say anything about a decarbonization flush.

“Correct me if I’m wrong, but carbon monoxide is a gas and would not really build up on a surface. I can see reduce carbon monoxide emissions, but not build up.”

I think they meant that the CO would increase in the exhaust fumes. That would be the case if the was less complete burning of the gas. But this is still an exercise in cash transfer.

Unless it’s running poorly, you do not need the cleaning. You also do not need to go to the dealer and specifically this dealer again. Find a mechanic that will do a better job looking out for your best interests.

I think this service should be done when hesitation occurs along with rough idle. this service is for the type of consumer who does not use injection treatment on a regular basis. this service just came out around 2005 and is relatively new to the business. i find it funny when motorage which i think is a publication for independant mechanics and other mechanics, recommends this service.

i find it funny when motorage which i think is a publication
for independant mechanics and other mechanics, recommends this service.

Is it because the makers of these flush machines spend their advertising dollars in Motorage?

My 140,000 mile, 92 Explorer has a ticktickticking that one would initially think to be a lifter noise. My tech knows it to be carbon buildup on a valve or more and when a cleaner is ingested the noise goes away…for a while, a week or so.

The buildup is on the neck of the valves preventing the full retraction of the valve on each cycle, leaving a slight slack at the top when the rocker arm is already coming back down. tick-tick-tick-tick.

So we clean it again ( using a vacuum line to ingest cleaner through the intake ), it’s quiet for a while, then in gradually begins to tick again. We have not yet decided to take the heads off the engine for the absolute repair.

---- here’s the conundrum ----

1 ) We seem to have waited too long to BEGIN cleaning the buildup and can’t seem to ever get caught up.
2 ) We know that many ‘‘cleaning’’ services are percieved as profit generators.
3 ) We know that preventive maintainence can be cheaper in the long run than repairing what could have been saved.

So then, At what point in the life of the vehicle do youall think a ‘decarbonization flush’ should have been done to have avoided this constant condition of not being able to clean it completely now ?

The O.P.s 100 k miles seems like a nice starting point.
Hindsight being 20/20 on my own truck, I’d have to wonder if I should have done the same at 100k ?

Carbon, is a by product of combustion. To get real carbon build up you need heat and pressure. These are not present, or shouldn’t be present, in the intake tubing, valves and ports leading up to combustion in the cylinder. If you have backfiring and flames getting past the intake valves and back up into the intake manifold, you have a problem - a big problem.

I think the substance they are calling carbon is purely dirt. Perhaps it has some gas mixed into the dirt and this helps it get a bit blacker and harder, but I don’t see how it can be “carbon” unless the motor is running like h—, with backfiring an obvious missfires.

I guess the problem I have is that it might not have helped you at 100k (it’s not helping now, that’s for sure), and that most cars never develop the carbon buildup problems. So when a person asks if their good-running car needs a ‘carbon flush’, I think the odds are very high that it doesn’t.