My car's engine had fairly clean valves at around 15,000 miles using Canadian Suoco gas. You could see where the carbon was building up, and flaking off at the same time. When my engine started to run rough after using cheap brands of gas in the US in 2005, just one tankfull of Canadian gas greatly improved the rough idle.
How to remove carbon deposits from valves?
- Thread starter Da Game
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Well, this may not quite qualify, but I dosed my tank heavily with MMO ..and had cause to pull the heads not long after. They were actually dirty compared to the combustion chamber/pistons .. it was a very soft soot. The plugs had the same soft deposits. A wire brush, without any real effort, dislodged the stuff. I imagine that it was only like that due to the amount that I used (about 10X the normal treat rate). The pistons and heads were pretty clean with no build up. It had about 160k/13years on it. The stuff was kinda "wet" soot. I guess that's that resin that they talk about when it burns
For really heavy carbon on valves save your money on the over-the-counter stuff. Theres only one product I can say without hesitation will remove hard carbon deposits on valves. It works every time but you sure better know what you are doing before you use it. WATER
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Absolutely. It's just a royal pain to do with one person. It always stiffles the combustion process. You also need a central manifold port or a central horizontal air horn. If you're injected, anything thrown in the tank goes to each cylinder ..garrenteed.
Here is a trick I learned from a tech. I used to work with. It will enable anyone to use water to clean combustion chamber carbon by themselves without anyone's help.
If the car has a washer fluid resevior that is in working order,make sure it has only clean water in it. Disconnect the hose some where close to where it connects to the hood of the car and run it to the intake in a place that it will be evenly sucked into the manifold. Take off down the road and intermittently press the windshield washer button in the car. DO NOT OVER-DO IT. You just want to feel a slight stumble in the engine. I press the button down and release it quickly. Don't hold it down. A little water is all that is needed.
1987-90 Camrys with 3SFE engines would carbon up so badly that they sounded like a rod was coming out the side of the block. Most were lady-driven cars that never got ran aggressively. Toyota tried walnut blasters as well as GM top end cleaner with no fast results. Many Camrys got a little drink of water and purred like a kitten.
It can be overdone with damage resulting if you don't exibit restraint and common sense.
If the car has a washer fluid resevior that is in working order,make sure it has only clean water in it. Disconnect the hose some where close to where it connects to the hood of the car and run it to the intake in a place that it will be evenly sucked into the manifold. Take off down the road and intermittently press the windshield washer button in the car. DO NOT OVER-DO IT. You just want to feel a slight stumble in the engine. I press the button down and release it quickly. Don't hold it down. A little water is all that is needed.
1987-90 Camrys with 3SFE engines would carbon up so badly that they sounded like a rod was coming out the side of the block. Most were lady-driven cars that never got ran aggressively. Toyota tried walnut blasters as well as GM top end cleaner with no fast results. Many Camrys got a little drink of water and purred like a kitten.
It can be overdone with damage resulting if you don't exibit restraint and common sense.
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I've even gone to the trouble of running a PCV line up via the cowl and into the passenger compartment and thrown it in a jug of whatever agent I'm using at 65 mph. Depending on your vacuum at the moment, you can just leave it in the jug or do a "quench/purge" type thing.
But the problem that still can poke up for some is that they need a central vacuum point. If you have a horizontal air horn the heavy mass of the liquid will be biased to the closer cylinders. Some engines don't have a PCV line, but a metered orifice to just one runner of the intake (like two of my engines) ..or no PCV at all (like one of my engines).
..but the basic practice and concept is the same ...
But the problem that still can poke up for some is that they need a central vacuum point. If you have a horizontal air horn the heavy mass of the liquid will be biased to the closer cylinders. Some engines don't have a PCV line, but a metered orifice to just one runner of the intake (like two of my engines) ..or no PCV at all (like one of my engines).
..but the basic practice and concept is the same ...
When I changed the intake manifold gaskets and fuel injector o-rings on my 1995 Ford Contour V6 (due to a fuel smell, it was the o-rings leaking slightly) at 125,000 miles, I was able to see the intake valves.
The intake valves that the fuel injector sprayed onto were clean.
The intake valves that did not get any spray from the fuel injector[1] were filthy, probably from PCV residue.
I had been using Redline CFSC in that car for the previous 30K miles.
I don't know if using Redline made any difference--the intake valves may have been just as clean without it.
[1]It is a DOHC engine with 12 intake valves. Only 6 of those are sprayed by the fuel injectors. The other 6 are not.
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