Need help identifying noise. Rod knock ?

[Charles Myers]

I have this 98 C1500 that knocks, I can hear it more at the botom near the flexplate and the oilpan.
It more audible when I start the truck but once it's warmed up you can bearly hear it. Rod knock maybe ?
Is it worth fixing this or just find a new engine ? It's got 190k miles.

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I had the the same problem. Turned out to be piston slap. I rebuilt my motor and the machine shop messed up a bore. I had to have the cylinder bored and sleeved. Took care of the noise. From what ive heard and read piston slap is not un heard of. Chevy gets lazy from time to time and the machining has alittle more play than usual. Some people live with it.... some people rebuild. It wont hurt if you live with it. It just bugs

 

[Schurkey]

I had the the same problem. Turned out to be piston slap. I rebuilt my motor and the machine shop messed up a bore. I had to have the cylinder bored and sleeved. Took care of the noise. From what ive heard and read piston slap is not un heard of. Chevy gets lazy from time to time and the machining has alittle more play than usual. Some people live with it.... some people rebuild. It wont hurt if you live with it. It just bugs

GM has had substantial problems with piston slap. It's not all about sloppy machining, it's also caused by pistons with excessively-short skirts. While I like short skirts on females, short piston skirts (lighter weight, less friction) causes the piston to be less-stable in the bore.

GM also says this does not hurt anything. Well, yeah...to a point.

If the piston slap gets bad enough to make the knock sensor angry, timing retards, tailpipe emissions, fuel economy and power are affected negatively. I've lost one or two highway MPG on my Luminas due to excessive piston slap.

 

[Chris D]

Get you a can of anti/seize and mix it with a 20w50 and put it in your engine. Read a thread earlier about it and he said it saved his motor for a while. The knock he had went away. Do a search in here and you will find it

 

[Scooterwrench]

Get you a can of anti/seize and mix it with a 20w50 and put it in your engine. Read a thread earlier about it and he said it saved his motor for a while. The knock he had went away. Do a search in here and you will find it

Ha-ha,thanks Chris. Yeah I'm the guy running antiseize in his motor but I know for sure that it's not long for this world. I only recommend you do that if you know it's a rod knocking or piston slapping and you just have to make the thing last a little longer. This is a patch,not a fix!!!

 

[Pinger]

Piston slap was my first thought - especially as it disappears as the engine warms.

 

[j 1985 chevy]

I have this 98 C1500 that knocks, I can hear it more at the botom near the flexplate and the oilpan.
It more audible when I start the truck but once it's warmed up you can bearly hear it. Rod knock maybe ?
Is it worth fixing this or just find a new engine ? It's got 190k miles.

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It sond like a deep knock pull the dust cover off the transmission and move it around should not make a knocking sond if it don't might be a rod or Maine dont sond like a lifter or timing change that not to say it is not but I Reilly don't thank so look a the oil but it probably will end up with you removing the oil pan if it's not the transmissions flix plate