I have been noticing a new noise that was previously only audible at over 70-75mph while towing. For last 1000 miles or so it has become very audible at all RPM ranges and loads and is progressively getting worse.


The best way to describe it is like a valve crackling louder than the normal diesel clatter. I hear it when accelerating or deaccelerating. Warm or Cold. Seems to be coming from the driver side of the truck, under the hood. The sound is not constant, comes in and out. No power loss, or mileage diff. Runs great except with this annoying noise. It could be something vibrating against something. I just can't figure it out.


Any ideas?

Exhaust leek? Maybe the downpipe is cracked? IIRC some LB7's had this problem.

My intial thoughts are deposits on the valves maybe, i'm no mechanic. I'm probably wrong a an engine with ~10k on it Thinking i could run some type of fuel cleaner through there just too eliminate the idea in my head.


Anyone recommend a good fuel treatment to help reduce deposits?

Pilot Injection?


Is it heard around 2800 ish RPM's?


Mac

It sounds like pilot injection quit on a cylinder, but this is any where from idle and up. Like one valve is a lot louder than all the others. Most noticeable when cruising down the highway at around 1800-2200 rpms.


I gonna take it in, or try too. I fully expect them to say, "Hey its a Deisel..."

Will took it out to Madisionville, approx 90miles, from my house, Sounded terrible on the way up there it was really getting bad in the hills. Truck sat for 2 days and i went home. No noise at all on the drive home, or into work this morning. Oh well i guess i'll never know what it was. Hopefully its gone for good.