When I start my 01 a loud knocking sound that appears to be coming from the left side. After I have driven the truck for a while the sound is still there but at a very low level. Is this normal when the vehicle is cold? What is the sound? A Belt? It truely sounds like it is from from the front area around the Belts.

Thanks

[This message has been edited by Gecko (edited 03-24-2001).]

 

Two opinions on that knocking sound.

Forged pistons: sound is perfectly normal.
Piston slap: need a new motor.

Piston slap is a loud diesel engine sound, anything less is normal. Do a search on piston slap...

Wav file of piston slap HERE

 

My '00 started knocking at 550 miles. Sounded like it was coming from the left bank. Did not go away when warm. After many trips to dealership finally met with regional customer service rep. He agreed that it sounded like crap. In a parking lot it could be heard 40 feet away. They replaced engine at 1500 miles. It has about 1600 miles on new engine. So far so good. No final consensus on cause. I was given the forged piston line a couple times. Wasn't buying.

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Silver 2000 Built 5/26/00
#3299 of 4966
Bone Stock
SnugTop Tonneau Cover

 

The sound is not coming from inside the motor. It appears to be around the belt housings. I had a 99 GMC 5.4 that would do the same at start up. New motor with only 800 miles on the truck I don't think so.

 

Finally, a good sound-byte thanks to DreaminAboutL.

The good news is...

...that noise is valvetrain (adjuster) noise -- NOT piston slap.



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Y2K™ Jim - N8JG@Hotmail.com

Toreador Red, Keyless XLT SC SB 5.4L E4x4 4wDisc/ABS, 3.73LS, Skid, HD 7700# Towing, LT-245's on Chrome, Tube-Steps, Captain's, 6CD, Tonneau, named: "Nick"

 

Ummm... ok... it is just a copy of the "piston slap sound" file from the monster Piston Slap thread: https://www.f150online.com/f150board...ML/000833.html

[This message has been edited by DreaminAboutL (edited 03-24-2001).]