I posted about a month ago that I believe I have a rod knock. My oil filter vibrated loose and dumped 6 qts of oil and I was runnin over 90 on the highway. Anyway...before I pull the engine, what's the best way to determine what the cause of the knock is for sure. I was thinking pull the pan, but that looks like I would still have to lift the engine for that. Then I was thinkin pull the head, but don't know if that would help.
All input appreciated, thanks.

 

How bout today ???

 

Get a stethoscope from Harbor Freight, a long screwdriver, or a piece of PVC pipe and put your ear up to it while moving it around the engine block. This will help to isolate the knock.

 

A rod knock. You might try opening an injector line for each cyl to see if can blunt the noise. Rod knock should get worse under load. A galled piston might do the same though.
Just six qts low seems like would be enough to save rods. Believe mentioned galled piston before.

 

I think on these cummins engines the number 3 cylinder knocks the most its a cummins thing. I know mine knocks hard but its fine interanlly.

Nick.

 

hmmmm. have to check it out more. The knock never really changes sound. It's just constant.

 

Thats probably not good then. I've had a "knock" since I replaced 2 injectors and 6 nozzles a few thoudand miles ago. Leave here for OKC Sunday empty, get there yesterday AM and leave with my trailers and really knocking now!So, I just plug along and made it home this morning at 7, Turns out I have 2 more injectors gone bad!!! Replacing all 6 with some very low mile units and see what happens next.... besides my flippin' wallet being empty!

 

Also "DO NOT LOOSTEN THE INJECTOR LINES" There is extrremely high pressure and cas cause serious injurys if you do. Sorry, that is the only contribuitation I can offer.

 

As somebody said before, REALLY bad idea.... The common rail engines run several thousand PSI, even at idle. That's a good way to get hurt.

 

The Death label should be enough to deter anyone from trying to do this.

 

Get a sample of your oil and get it analized. That would at least eliminate the thought of an internal problem.

 

Do you think the fact that i added 6 qts of fresh oil to the engine hinder any test results ? Also, do i have to be a chemist to interpret the test findings ? Or do they explain what the test reveals ? Thanks, Dan

 

Blackstone does a pretty good writeup. No chemist needed.

 

DO NOT CRACK LINES BAD IDEA
drain the oil and sample it look in the drain container for metal

 

...and also on the loosening of injector lines. The common rail trucks do NOT have injection pumps. Your pump is merely a high psi pump. The fuel log, lines, and crosstubes are nothing but a high pressure resivior of fuel. Loosen any of the six lines and you'll have the same effect on all injectors. The injection event is at the injector itself controlled by the ECM. Best thing going would be to cancel the injectors with the DRB scan tool and listen for a change.....HOWEVER, this isn't always a sure shot either. If the injector is leaking it can still make a notable "knock" even when the power is cut to it. Only other method would be to remove one line at a time from the fuel log and "cap" the line on the log and then start the engine. Do each one separately and see what happens. If you determine one cylinder making a noise you can swap the injector with another cylinder and see if the knock moves with the injector change. If the "knock" moves, you know you need an injector...... if the knock stays at the same hole, you need a bucket full of money.