noisey duramax

[denverdale]

I have a 2002 silverado 2500 hd d/a with 117000 miles. I am presently returning from Alaska. I made this trip before in 2006 pullling a 13000 pound 5th wheel. This trip has the same truck and trailer but it seems to me that the motor is extremely noisey - specially under load.
The truck is mostly as it came from the factory, including the exhaust.
I would enjoy comments from the experienced people on this forum regarding the following:
1. Could the excess noise be caused by worn timing belts/chains causing a retard or advance condition for timing and injection.
2. The truck has a terrible drone at about 45 to 55 mph. Could the drone be caused by a worn out muffler (loose baffel, etc) and could that contribute to the louder engine noise.

I have had good luck with this truck, but between the road noise and the engine noise, I way have to look at trading.

Any comments would be appreciated.

Thanks
Denverdale

[DmaxMaverick]

A lot of things happen over miles, and especially time. Insulators and isolators get hard, worn, or missing. Engine and transmission mounts harden. Metal fasteners tighten, and loosen. Your truck's been doing what it's been doing for over 10 years. When my 2001 was new, and for a long time after, it was so quiet I didn't have to shut it off at a drive-through. Can't do that now.

Tire noise is another factor. OEM tires have a purpose, and it isn't longevity. It's to sell trucks. They aren't the same tires you'll buy at a tire shop to replace them, even if the brand, model and size are the same, and even if you replace them at the dealership. There are exceptions, of course, and they only apply to high performance and emergency vehicles (police cars, fire trucks, ambulance, etc.). I've retired a few emergency vehicles, from new, and the difference is huge. Some cruisers and a couple trucks (all Chevy's at the time). The cars were always the same with tires (Goodyear Eagles), but the trucks would run through the first set of tires in about 10K miles or less, and 20-30K after that. Trucks are ordered the same as any regular buyer, as they're only purchased a few at a time, with no special "emergency vehicle" specs (those are added later), and the cars are ordered as fleet police vehicles (thousands at a time, for several departments in one purchase order), with the police packages. Crown Vic's suck, and the last real cruiser died with the Caprice/LT1 package. Sorry, got a little nostalgic....

That said, to my delight and surprise, my 2001 has been the most trouble free, rattle free, squeak free truck I've ever had for 200K miles. Yeah, it's more noisy than when new, but it's a lot less noisy than any other vehicle I've had or seen after 12 years.

If you notice some new noises, by all means, investigate them. The drone, probably hardened hangers. Diesel mufflers deteriorate from the outside-in, and are generally a lifetime component if they don't rust off from road salt. Also check the downpipe mounting tab. They're prone to crack where they bolt to the rear of the exhaust manifold. This can cause a vibration or drone at certain speeds or engine loads. This can be seen if you lift the passenger side fender skirt, to the upper/rear of the tire. If it's cracked, just have it welded in place.

[rapidoxidationman]

could the extra noise be the radiator fan fully engaged? Any temperature differences between the first time you did the trip and this time?

[Kennedy]

Fuel quality, elevation changes (timing) temperature, humidity, etc all play into the sound level.

[denverdale]

Thanks for the input. I should have mentioned earlier that the engine really sounds like an old sewing machine or sort of like the old ford diesels sounded.
As far as the road noise, I run michelins on the truck and I know they can be noisey on certain types of pavement. I can live with that, the drone and loud engine - well I'll to see about that.

denverdale.

[Kennedy]

Try removing your power adder once and see how this affects the sound. Harness boxes are not the best way to add power and can cause timing rattle easily enough. Cetane boost also tends to help.

[denverdale]

Good suggestion. I have tried setting it on "o" with no change, but, I'll remove it completly.

denverdale

[More Power]

Crawl under the truck behind the passenger side front tire to an area where you can see the first section of the exhaust downpipe. Now, have someone grab the tailpipe and pull/push it forward/backward.

Can you see the downpipe move forward/backward?

If so, the first section of pipe that bolts to the turbocharger may have a problem...

Jim