Name that tune!

[willscary]

Hi everyone. Long time lurker, recent member, new poster. I just sold my 1991 8600 gvw base 2wd pickup and bought a 2003 2wd 2500. Old Blue had just over 285,000 miles on it, and the only problem I had was a 5 time bad starter and a wrist pin that failed at about 220,000 miles. So is sold it and bought the 2003 work truck 2500 automatic (33,000 miles) for under $12,500 out the door. I was thrilled at having a vehicle that had been owned for exactly 300 days and obviously had a lot of highway miles on it. It starts and runs flawlessly, idles like it isn't even running, and has a LOT more power than Old Blue had. Not a squeak or rattle can be found. The truck is solid as a rock, just like the old commercials.

 

Here's the problem. When I bought the truck I asked the dealer to change the oil. The truck sounded like it pinged just a bit under acceleration when I test drove it. After I bought it and got the oil and filter change, I noticed the noise more. I took it to another dealer and asked them to look at it under warranty. The service manager (whom I have trusted for almost 2 decades) heard the ping and said he would take a look at it because it sounded a bit abnormal.

 

I guess the best way to describe the noise from inside the cab is that it sounds like a bunch of mice are playing mini tambourines. From the outside of the truck it sounds like I am dragging a small chain on the pavement. The niose happens warm or cold, and only under moderate acceleration. At low acceleration the motor is smooth, and at higher acceleration all I can here is the air intake and the exhaust. The sound reminds me of the broken wrist pin in Old Blue, but I am quite sure there is absolutely no power loss like there was in Old Blue (this truck hauls ass!)

 

When I went to the dealer to pick up the truck after service, the guy I trust said that they put in 2 computer updates and that everything checked out normal. He then said that he talked to another GM service guru who told him a little pinging is normal.

 

Here's another rub...my first 2 tanks of gas were over 17 mpg, and now I put premium and a fuel system dryer in it and it still pings the same. If I turn the radio on to normal listening, you can not hear the pinging, and in the rain the wet pavement and rain on the windshield are enough to drown it out.

 

What is the noise and should I be worried? I have about 2000 miles of warranty left. One more thing...I tried out a brand new (6 miles on the odometer) 2500HD crew cab LT 4wd that made pretty much the same noise under the same acceleration, but not quite as loud (maybe due to better sounddamping in the cab?). I don't want to worry, but the price seems awefully incredible, and now I am wondering if they just wanted to get rid of a defective vehicle.

 

Thanks for any help and comments!

[cbz2500hd]

Try going into the heavyduty forum and look for the article that reads "THAT RATTLESNAKE SOUND". Sounds like the noise alot of us have

[willscary]

Thanks. I have been watching that thread for a few weeks now, but it does not seem like my noise. GM tech came closest to the sound with valve noise, and if I open the hood I can hear it at idle from a foot away from the motor. However...it is not csk. I have had CSK on my '98 Chevy prizm since I bought it, and my sister has it on her Toyota also. The CSK is only for a few seconsd to a minute while it is cold, then goes away. I still get 43 mpg with my prizm 5 speed and have never used any oil. It has almost 150,000 miles on it. This sounds like my broken wrist pin did. I only happens under moderate acceleration. At cold start and warm start, at idle at a light or stop sign, crusing down the highway or city street, the truck is quiet. Coasting it is also quiet. I only get the noise under moderate acceleration, such as medium acceleration from a stop or when climbing a medium incline hill while the cruise is set. I could see valve or lifter noise, and once again, it does not go away when the engine warms up.

[seadoons]

First off, welcome to the board! I have a 2002 1/2 ton with the 5.3L and I just rolled 60,000 this weekend. Mine has made this exact same noise for a very long time...took it in under warranty and got the "its normal" line. The truck still runs perfectly and has never consumed any oil...there are a lot of people here that have way more miles on their motors than I do and they have had no problems even though they have the same noise.

[Quadrasteer]

I have a noise that sounds similar. When you first start the engine or if you let it idle it sounds like the valve train is not getting enough oil. It sounds worse when you first take off and then goes away. If you let it sit and idle the noise comes back. I'm using Mobil 1 10-30 and that might add to the problem. I'm taking it into the dealer soon, wish I knew more before they give me a line of BS.

[Rookie]

Check the heat sheilds on the manifold. I had one the sounded exactly like i was dragging a chain/tin can. Just a thought?

[willscary]

the heat shields? Too close to the manifold that they rattle on vibration at a certain RPM? Loose bolts? What should I be checking? This is the first time someone has described a noise like mine that was not temperature/time dependent. Please tell me more!

[willscary]

anybody else have an idea?

[Rookie]

Yea, the thin metal cover over the manifold. sometimes a weld will pop or screw will come loose. The shields on mine was right by the spark plug wire to protect them from the direct heat of the manifold. Again just a statement from my past experience.

[dukbludvl]

random thought - any chance it's the exhaust system expanding and contracting? my Yukon makes a pinging sound... but, it sounds like it's coming from the underside, not the engine compartment.

[Wild4kst8]

i hate to say it, but....do a search for pistonslap on msn

[willscary]

OK, so I did not think it was piston slap. I heard about the dreaded disease a few years ago and had heard that they redesigned the pistons in late 2002, so I wasn't worried. When I bought the truck a few weeks ago, I drove some brand new trucks that sounded similar. Unfortunately, I never listened UNDER the motor. I just went outside after reading that a ping at the top of the motor is probably no big deal, but a niose at the bottom IS a big deal.

 

I could just about cry! (or slam my head against a wall). My truck, that I was dumb enough to buy from the local dealer just a few weeks ago, sounds like a diesel from underneath the tranny/oil pan area. This has got to be a bad dream. Do the rest of you have this sound? It is NOT the pinging I hear from the cab, it is a clack from the bottom.

 

[JBZ71]

This is way out there but, if it's an automatic,check your trans dipstick tube..I've read where they might be too close tot he firewall and cause some noise by hitting/rubbing against it...Maybe??????