Diesel 3000 rod knock at idle

[Laneman]

Oil pressure is another thing I am thinking about. Makes sense to me that pressure would increase with rpm, so a worn pump might have low pressure at idle. I think 1st thing is to change the oil and filter. Next is either mount a pressure gauge or test the injectors as recommended here. It does have an idiot light that lights at initial crank-up then goes out once engine is running, but I'd rather see actual pressures.

 

[Soundguy]

as long as the light goes out.. you have some pressure.. but no telling how much. I don't know the spec on the sender.. but I have seen som ethat go out at 6psi.

I'd put a mechanical gauge on it even if for only a hour of run time to see what the pressure did at startup, then cold idle, cold throttle, and hot idle, and hot throttle.

do change the oil and clean the injectors with a double dose..

ps.. you can use a wrench to crack an injector line when running to see which cyl the knock is related to.. if it is anyway..

post back.

soundguy

 

[AGRIMAN]

I知 not suggesting this is the cause of your low RPM knock, but I have seen this happen more than once. A crack shaft will break just forward/behind a main journal and continue to run without causing any apparent issues other than a low RPM knock.

The first time I seen this happen, I wrote it off as an odd occurrence mainly because I had never seen or heard of it happening before and it seems impossible. I have seen it happen twice more since then. At a idle, you could hear a hard knock in the engine(sounds like a rod), but above 1,200 RPM the knock goes away and the engine runs smooth. No knock or vibration.

All of these were large tractors (over 130 hp) and I have never seen it happen on a 3000, but I would say its possible. Obviously, this isn稚 a good thing and I can稚 say why or for how long a engine will run, but I do know that one of the tractors was ran for over a half a day (under heavy load) after the knock was heard before I stop it.

I do agree with a possible fuel system problem.

 

[Gale Hawkins]

My diesel 3000 occasionally knocks at low idle, only after working it hard. During normal operation it doesn't do it. If I raise the throttle some it goes away. I bought it a few months ago, seller said engine was recently overhauled.

The 1976 265 MF hammered so much at idle it was hard to tell what was what until I started using WM TC-W3 outboard motor oil at a 1:128 ratio in the fuel. It has under 1300 hours since new.

I just changed from 15W-40 Rotella to 5W-40 Rotella T6 synthetic. I just have just driven it to its parking spot since going to synthetic but I swore it was even more quite with the synthetic. I was not even thinking about that possibility yet the quiteness caught my attention.

Adding a FEL may make it sound louder like parking next to a building can.

Best of luck.