[MoParFish]

Hi All,

I've got a kind of ticking, almost a knock that increases with engine RPM and varies with load. Its sounds very similar to an exhaust leak on a gas motor. I can't really hear it with the windows down. (Am I being too picky?). Runs Great. Starts great. Boost is over 25 when pulling hard. No abnormal sound at Idle. Ran the valves, no change. Oil looks good. Oil pressure has been consistent. Has a little blowby but nothing I would consider excessive. Looked for blown exhaust gaskets or cracked manifold but didn't really see anything. Never overheated. Has been making the noise for maybe the last 8000 miles or so and has got maybe just slightly worse over time. Truck is basically stock with a straight pipe. Should I keep the windows down or just turn the radio up? I realize it's very hard to diagnose noises over the internet but, any ideas? Thanks...

 

[MoParFish]

P.S. The noise kinda stands out because It sounds like it's the frequency of just one cylinder. Thanks

 

[jcarl735]

run the rack on the old girl. that could be causing some of that blow by too. just adjust all the valves

 

[clc]

It sounds like you have checked a reasonable set of items.

I am not saying this is it but one possibility is a leaky/partially stuck open injector. Often they make no noise at idle but knock at higher power settings. I have never had that happen on one of my Cummins but I have had it happen on farm tractors and cured the problem by dismantling the injectors and cleaning them.

If you don't find a simpler solution and you want to inspect the injectors you could pull the injectors and take them to a local diesel shop for cleaning, inspection, pop setting, and flow testing. Alternatively you could take this opportunity to upgrade the injectors.

 

[[email protected]]

First thing I would do is take a large screw driver and put it on the head buy the injectors, with the handle on your skull, buy your ear, you should be able to hear each cylinder firing. second is to take off the oil filter and cut it open, gasket end down and inspect it for brass or bearing material. Third do a drain plug swap to look for abnormal amount of metal on the drain plug. When it is cold use soap and water in a spray bottle and cheak for exhaust leaks. PLAY SAFE!

 

[MoParFish]

Thanks for the great ideas for things to check. What do you guys think the chances are internal engine damage? From what I hear 185k is not much for these 12 valves but leave it to me to have a bad one. Hopefully it will be a just a bad injector or an exhaust leak. By the way, No noise on decel. Thanks Again...All is Appreciated...

 

[rcsund]

I had a 6.5 TD that was doing the same thing. It was a bad injector that was leaking.

 

[clc]

jpringle3's big screwdriver stethoscope is a great way to isolate bearing noises, too. Just be careful when you put your body parts near a running engine that you don't get something you'd like to keep tangled up with moving parts.

 

[MoParFish]

Well, I think I've narrowed it down to an injector or two leaking. I drained and strained the oil with nothing noteworthy as well as cut the oil filter open and nothing there either with about 3000 miles on the oil & filter. I figure that's good? My dilemma is I've never pulled an injector in my life but have pulled many spark plugs. Something tells me there is more to it... I kinda want to pull them myself and take them to have them tested. #1 to save money #2 I hate taking vehicles to a shop. Any opinions on this. I do most of my own mechanical work but very new to diesels. Thanks for all the help...

 

[MoParFish]

P.S. Getting a little louder as time goes on

 

[illflem]

Removing the injectors is no biggie.
Remove the injection and return lines totally, don't bend them out of the way.
After removing the nut that holds the injector down slip a piece of pipe or fitting, metal or PVC about 1-1/4" long over the injector. With a washer or two screw down a lug nut removed from your front wheel onto the injector. They will easily pop off.
Best to replace the old injector and return washers with new ones.

 

[jcarl735]

and when you put in new ones ANTI-SIEZE em so you dont have too much trouble if you ever need to take them out again. get a set of pesacola diesel injectors. stage 2s should give you a little power, smooth it out and theyre onnnllyyyy $200.00 for 6 man!