Is this normal?

[BigLakeDMAX]

I'm still getting used to the DMAX, having moved up from a '97 6.5l K2500 and am wondering about a couple of things. The truck as an '02 2500 CC, two months old, with 6200 miles on it. We're running winter fuel here now and I'm using DFA with every tank. I've noticed two things that have me wondering - and both have been present since the truck was new.

First, there's a tap sound from the right side of the engine. When the truck is just started, the exhaust has a pronounced tapping sound - a metal on metal sound - which is very rythmic - about 300 times per minute. This is most noticable at the tailpipe. Once the truck warms up, this tapping becomes much quieter at the tailpipe but I can then hear it through the passenger side front wheel well. The driver side just sounds like a diesel. I also have the Duramax Tick, and this tapping sound is definitely something different. If it was a gasser, I'd think I had a bad lifter. After reading several posts here, I'm wondering if I have a bad injector?

The truck seems to run smoothly with lots of power. No smoking, other than white-blue smoke immediately after a cold start and then only for a minute. The only other thing I've noticed is that under a light acceleration at 40 - 60 mph or so, the engine sounds a little rough - almost like an exhaust leak (my dealer checked for this and said they couldn't find one) - however it doesn't seem to run rough. But, definitely not as smooth a sound as my old 6.5. But, more power and better mileage, so if it's just some new sounds I need to get used to, that's fine.

This sound familiar to anyone else?

[Dawg]

Sounds like you have the "Tick". GM put info out on this and it appears to be harmless and goes away after some time. If you do a search for the "Tick" you should find a lot of info. Others with much more experience than myself can give you the details of the tick. My truck had it for a short time. I haven't heard it in a long time.

[FstTrack]

Mine has 27,000 and still has the tick now and then. doesnt seem to be a problem.

[DmaxMaverick]

BigLakeDMAX

Look through the passenger side wheel well, under the liner at your turbo downpipe with a flashlight. You may find that one of the brackets that secure the downpipe is cracked vertically. Seen this on a few of them and the noise is about like you describe. Mine had to be welded.

Sound like you have two noises, one being the tick, on the driver's side that sounds like a mechanical typewriter.

Good luck.

[Ranger354]

Over 14,000 and mine has the tick also. Just figured it was the engine and normal. I plan to look into the other noises closer.

[mackin]

BigLakeDmax

Is this what your hearing??????
=>http://www.csimo.com/junk/duramax_tickticktick_noise3.wav

If you use the search feature you'll get more reading info then you will desire on this subject.......Bottom line IMO and others, don't sweat it......


MAC

[BigLakeDMAX]

Mackin - I definitely have the tick as well and it sounds just like the sound file you sent.

The sound I'm concerned about is a heavier tapping or light knocking sound. The tick seems sporatic in timing and not nearly so heavy a sound, whereas the tapping sound is very regular in timing - about 300 per minute at idle (600 rpm according to my stock tach).

DmaxMaverick - thanks for that tip - I'll check that one today. It may be - the sound seems to come from the rear passenger side of the engine.

[hoot]

I had the tick pretty bad. Hated it at first. I slowly got used to it then around 10,000 miles it started to come and go. At 40,000+ It's entirely gone.

[pullinpower]

Now that you mention it hoot I had the tick early on and at 41k I havent heard the tick either in a long time,even after an oil change.

BigLakeDMAX,I would just run the fire out of it and see if it manifests itself.May just need the soot blown out :D

[ 12-09-2002: Message edited by: pullinpower ]</p>

[BigLakeDMAX]

Thanks for all the replies - I dropped it off at the dealer tonight. They're letting it sit out so they can do a cold start on it tomorrow morning so their diesel tech can hear it. The service advisor seemed familiar with what I was hearing and wanted it in right away. The guy who moved it to the lot asked the advisor if this was another one in for "the knock" and the advisor said, "yep." We'll update on what they find - or don't find - when I hear from them.

This dealer is great - I quizzed one of the service managers about some mods and their affect on warranty. Amsoil Dual Remote system? No problem. Additional fuel filter? Sounds like a good idea. 4" exhaust? Wouldn't recommend it on a gas truck but sounds fine for a dmax. Exhaust brake? Good idea. Another customer put one on his truck and no problem. I think I've found a home!

Don