loud noise, banging from pass. side

[tankertoad]

Recently purchased K3500 Crewcab Dually 5-speed. PO said had loud knocking noise.Was not running at time of purchase. PO had started to remove components from top end. I replaced all glow plugs and injectors and put it back together. Starts and runs great, but does have loud noise from pass. side. Does increase in speed with RPM, but does not change pitch. First experience with diesel engines, but am looking forward to using this hauler to support my car collecting hobby. TIA, John.

[86DuallyCrew]

Is the front driveshaft on the 4x4 trucks on that side? If so could it be a bad U-joint? Since it increases with speed? Just a thought, or a bearing etc in the front running gear. Does it do it at idle?

[tankertoad]

Thanks for the quick reply. This happens stopped and moving, in or out of gear. Sounds similiar to rod knock, but no change in pitch with increased rpm. Suspect rocker or push rod problem, but hesitant to start taking it apart. PO had lower end rebuilt at dealer 30k miles back, new rod & main bearings. Would not suspect problem there, but I've been really wrong before! Thanks.

[sidehackbob]

MY vote is valve train related... valve springs break, rocker keepers give up and let rockers move sideways.. good luck

[Robyn]

What speed does the noise run?
Crank speed or cam speed.

If its cam speed it could be valvetrain but if its crank speed the little creature may have injested something like a glow plug tip ot it may have lost a wristpin bushing and a piston is smacking the head

Try loosening the high pressure fuel lines one at a time and see if you can locate the offending hole.

You may also try removing all the glow plugs and turning the engine over by hand to see if there is something hitting.

If you can find it by cutting out the cylinders then I would suggest yanking the head off that side.
If there is a piston crashing into the head it will be evident as will any foriegn materials on top of the pistons.

Good luck

Robyn

[hamold1]

See my post a couple pages back on Tapping Noise thread.

Chris
2 1993 6.5td 4l80e

[drewkeen]

This thread was over a month old.

[oilburnertoo]

I had a bad vacuum pump make a knocking noise once, pull belt and run engine for short time and see if knock goes away.