Jeroen Distinguished - BHPian

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Re: Engine Decarbonising - Demystified Quote: SS-Traveller Originally Posted by Attachment 1061995

Before you decarbonise, please consider the following: Decarbonising a modern emissions-compliant fuel-injected petrol / common-rail diesel engine isn't really warranted and doesn't improve engine health to any great extent.

Frequent decarbonising is a procedure best avoided, by all expert opinions. Most automobile manufacturers (Tata is an exception) don't recommend decarbonising as a routine maintenance procedure.

Have you properly troubleshot the real reason behind your engine running rough / sluggishly? Is it really carbon deposit that is causing the problem?

Is the mechanic performing the procedure aware of what he is doing? An 800cc petrol engine doesn't need as much decarbonising solution as a 3.0L diesel does. Overuse of decarbonising chemicals is harmful to your engine.

Decarbonising an engine that is 100,000+ kms old could actually increase its fuel and oil consumption. Either way, don't expect a radical boost in FE after decarbonisation, whether your engine is old or new.

The perceived improvements (post-decarbonisation) are temporary, for just a few thousand kms, before the engine goes back to its old ways.

There are no scientific evidence-based studies that attest the effectiveness of these proprietary machines and chemicals.

The carbon emitted from the exhaust (in the form of smoke) pollutes the air you breathe.

Decarbonising isn't cheap. It is easier and cheaper to carry out preventive maintenance; pure fuel supply from reliable pumps, timed oil changes, higher quality oils etc. are effective in preventing / reducing carbon buildup To conclude, chemically decarbonising an engine isn't the cure-all that manufacturers of such equipment and chemicals tout them to be. There are pros and cons to carrying out the procedure, and I personally do not recommend decarbonisation, especially for an engine that is running in a healthy state. That said, the procedure can be considered as a last-ditch measure after all other options have been explored , in situations where engine performance remains poor, and you are keen to try something a little less 'invasive' before opening up the engine.



In the end, it's your car, and it's your choice.



Image Credits : The pictures of this Article have been sourced from various Team-BHP threads. Thanks to BHPians for shooting & sharing them. To conclude, chemically decarbonising an engine isn't the cure-all that manufacturers of such equipment and chemicals tout them to be. There are pros and cons to carrying out the procedure, and I personally do not recommend decarbonisation, especially for an engine that is running in a healthy state. That said, the procedure can be considered as a last-ditch measure, in situations where engine performance remains poor, and you are keen to try something a little less 'invasive' before opening up the engine.In the end, it's your car, and it's your choice.

I agree with the various considerations you list. Interestingly enough, my Jaguar dealer in Kansas City used to promote a fuel additive. Cant remember what is was, but it was supposed to do the usual, reduce carbon build up, keep injectors clean etc. etc. Never believed them.



Only once did I have an engine decarbonised. Many years ago I owned a Volvo 340DL. This was a carburator engine, no catalytic convertor. It kept suffering from pre-ignition and knocking. The Volvo dealer brought in an expert and even he couldn't fix it. But he ultemately suggested decarbonizing. They added something to the fuel and left the car running for 30-60 minutes or so, maybe we even drove a bit, cant remember. By that time the engine was definitely running very differently. Volvo than managed to adjust and tune the engine properly and the problems never returned.



So very likely that the knocking was being caused by considerable carbon built up in the cilinder and cilender head. Somehow this treatment managed to get rid of sufficient quantity, so the engine could be returned to normal.



Again, this was probably more than 30 years ago. These days with modern diesel/petrol cars its hardly a problem.



I generally don't believe in any add ons to fuel or oil. With the exception of fuel stabilizers which actually do work. (if you buy the right one!)



Jeroen Thanks for an excellent overview.I agree with the various considerations you list. Interestingly enough, my Jaguar dealer in Kansas City used to promote a fuel additive. Cant remember what is was, but it was supposed to do the usual, reduce carbon build up, keep injectors clean etc. etc. Never believed them.Only once did I have an engine decarbonised. Many years ago I owned a Volvo 340DL. This was a carburator engine, no catalytic convertor. It kept suffering from pre-ignition and knocking. The Volvo dealer brought in an expert and even he couldn't fix it. But he ultemately suggested decarbonizing. They added something to the fuel and left the car running for 30-60 minutes or so, maybe we even drove a bit, cant remember. By that time the engine was definitely running very differently. Volvo than managed to adjust and tune the engine properly and the problems never returned.So very likely that the knocking was being caused by considerable carbon built up in the cilinder and cilender head. Somehow this treatment managed to get rid of sufficient quantity, so the engine could be returned to normal.Again, this was probably more than 30 years ago. These days with modern diesel/petrol cars its hardly a problem.I generally don't believe in any add ons to fuel or oil. With the exception of fuel stabilizers which actually do work. (if you buy the right one!)Jeroen