Cat D6C loud noise from engine

What's the s/n of this D6C? Sure seems like a pump timing issue.

If you think it is the injection pump timing problem, check the injector timing before tearing into the engine.

I believe if the pump is in good order you should be able to spill time it, or alternatively I assume pin time it. The tractor looks like it might be a none turbo model from the little I can see in the video.

What's the s/n of this D6C? Sure seems like a pump timing issue.

I believe if the pump is in good order you should be able to spill time it, or alternatively I assume pin time it. The tractor looks like it might be a none turbo model from the little I can see in the video.

Hi Team,
the noise seems normal on the left side of the engine but louder on the right near the Injection Pump so one could suspect there is a problem in the injection pump.

A mechanics stethoscope would be helpful in locating the noise source.

Touching something like a screw driver, stick with rounded ends, against different areas of the Injection Pump and the handle end against your ear may locate the noise source to better diagnose.
Often used a long screw driver in the field to locate noise sources.

Are the injection pipes original to the machine as they look to be not original to cylinders No's 4, 5 & 6 ?

Injection lines are a particular length and some have more coils in them to make them fit close to the injection pump and the ones far away are straighter.
Some of the rear lines are oddly routed and two may be crossed.

The pipes also have definite inside diameter, if a pipe from another engine has been fitted with a different inside diameter then the injection timing to that cylinder is changed and symptoms like you have can occur, a difference in injection pipe lengths can affect timing too but not as much.

If you have not yet tested which cylinder is possibly making the most noise, try loosening each injection pipe in turn, one at a time, to isolate the faulty cylinder.

I recall a No12 Motor Grader, with same engine, making an odd noise and found an incorrect bore injection pipe fitted when I isolated the faulty cylinder by loosening the pipes one cylinder at a time.
From memory Turbo or maybe Turbo Aftercooled engines have different bore injection lines to a Non-turbo engine.

Cheers,
Eddie B.

[quote="edb"]Hi Team,
the noise seems normal on the left side of the engine but louder on the right near the Injection Pump so one could suspect there is a problem in the injection pump.

A mechanics stethoscope would be helpful in locating the noise source.

Touching something like a screw driver, stick with rounded ends, against different areas of the Injection Pump and the handle end against your ear may locate the noise source to better diagnose.
Often used a long screw driver in the field to locate noise sources.

Are the injection pipes original to the machine as they look to be not original to cylinders No's 4, 5 & 6 ?

Cheers,
Eddie B.[/quote]


Hi Eddie,

Thanks for the suggestions.

This was what my pickup mechanic did. Used a metal road to listen for the source of the noise and he said it's not coming from the engine.

All the injections lines were like that when I bought the D6C (at least that's what I can remember), problem only started after the mechanic refitted the fuel pump which he took away to service. Nothing else was changed.

Will try checking the lines...

Hi, Valeo.
First, a question for edb - Eddie, I know that yoy can't answer this one with any great degree of certainty 'cos you weren't looking over themecahnic's shoulder when the service on the pump was done but is it possible that one injector pump is not up to scratch right after a service?

Next, if you trace to noise to one particular cylinder, try swapping that injector with another from the opposite end of the engine and check to see if the noise moves or stays where it was. That will tell you if it is the injector or something else. If it stays where it was originally, then you probably need to start looking at injector pipe lengths and bore sizes or maybe a faulty injector pump.

Also, if all the injector pipe clamps are not correctly installed, that may be a contributing factor.. If somebody could post a photo of the injector pipe layout and the proper clamps, that may help.

You can use that 'stethoscope' trick on the injector pipes too - may just give you a clue.

Just my 0.02. (But what would I know? I'm just a 'pore, dumb bulldozer operator'.)

I am certainly not a diesel mechanic, but I have worked on gasoline engines and some diesels since I was 14 years old. When a new problem arises, especially in the area where the last work was done, 90% of the time that is where the problem is. I sure would scope out all things about the pump before considering anything deeper in the engine. Coincidences do happen but mostly not. I believe your pickups mechanic is on the right track. Just me.