What is this ticking sound coming from my motor while idling?

I have a 99 GMC Sierra 5.3l v8 350 motor

the truck has 142k miles on it

I dont know if the timing chain has ever been changed

Could you tell me what could be the problem, and how much it will cost to fic?

Should I replace the chain? cost on that?What is this ticking sound coming from my motor while idling?
it most likely just valve tick, pretty common on the V8. if its valves ticking then its really not a problem more of a annoying thing. higher octane fuel cuts down on the tick

but you don't have a 350 you have the new 327 the 350 is 5.7lWhat is this ticking sound coming from my motor while idling?
The timing chain should be good for the life of the engine. It is more likely something in the engine head, probably worn out valve train. Expect to pay about 10 hours for labor for removal and reinstallation of the heads, plus probably about $500-$600 for machine work, if that is indeed the problem. Have a mechanic check it out to verify what is actually going on. Most will probably take a quick look at it for you for little to no charge,What is this ticking sound coming from my motor while idling?
that is likely a lifter that wont pump up good. if the engine pops and backfires or has a miss etc. its probably the lifter is ground away completely. if it only ticks at idle its likely the lifter valve/piston is just stuck. you will probably need to tear it apart to fix. make sure your oil is good.What is this ticking sound coming from my motor while idling?
How is the oil? have you checked the level and how many miles.



you may have bought gas with water in it. sometimes if you park you truck with an empty tank, it will rain and when you go to start it, the condensation will make it do that.



Take a pipe or piece of hose and run it around listening in one end of it to pin point the location. It could be bearings in the smog pump or something like that.