Thats a neat trick, you could probably pin down which cyl it is now.

 

I thought I'd post the latest update in my battle with the "engine noise". Someone on this forum mentioned Stoney Creek Cat (Ontario) was pretty good at fixin' Cat machines ... I was pulling a fully loaded trailer (44,000 lbs) and decided to stop at their shop on my way to Buffalo, NY border crossing. I described the problem and how I'd been to so many shops doing top sets, looking for exhaust leaks, doing DYNOs, adjusting fuel settings, etc.etc.

Anyway, I said - "I'm fully loaded and the noise is much clearer than when I bobtail. Why don't your mechanic come with me for a quick ride on the QEW?" They introduced me to Bruce, the mechanic. He hooked up his laptop to the truck and checked things, then made push Accelerator to maximum RPM with engine break on, every 5 seconds or so ... while he was crawling in the engine compartment (how he withstood the noise from the 500 hp beast - is beyond me He didn't find anything wrong...

So, we went on the interstate and when I pointed the clanking/ticking noise to him, Bruce listened for a sec and then said, "It's not the engine." He put his ear to the gear shifter and added, "It's the transmission... or your clutch. Let's ride some more."

He kept listening to the noise which appeared above 1200 rpm and asked me to depress very slightly the clutch while we were cruising - and my right foot was still on the accelerator. I did that and ... the noise disappeared!!!

"it's the clutch," said Bruce now with conviction. I turned and shook his hand. "Bruce, you're a wizard! No one has been able to identify this noise before.."

Anyway, we came back to the shop and he put a bungee cord somewhere inside the clutch from underneath the engine (he said years ago Freightliner had a workaround similar to that for 'noisy clutch"). When he was done, he said he couldn't guarantee this patch will work, but at least now I knew what the problem was. It was nothing serious and - most importantly - it wasn't the engine.

When I started driving towards Buffalo again, the noise was still there but now it disappears completely when I go downhill. Before it was there all the time. I'll stop by my International dealer next time I'm near Woodstock - I'm pretty sure they will be able to fix it - now when I know what it is that needs to be fixed

So, there you go. My "engine noise" turned out to be a clutch noise with no defects/leaks in the engine.