I am a newbie to the site and I am hoping the best in solving a problem i currently have with my 99 GMC,jimmy 4.3 engine. the engine has about 149,000 miles and most are highway. I have babied this truck for the last 50,000 miles when I acquired it off the original owner who babied it from new.I took a trip for work and in total travelled 2500 miles and after I got back home I noticed in the next week that a small ticking had developed in the engine. when driving after the vehicle is warm you can notice this ticking more when you take your foot off the accelerator, and you can hear this engine noise as your between shifts. When I start the engine cold you will not hear this noise for 10 to 15 minutes until the engine oil warms up and after that you can hear a rattle as if it is a lifter, I have taken the passenger side valve cover off and ran the engine and checked all the push rods by adding pressure to them with the help of a screw driver and no unusual chatter. My question is: are these engines known for this, could it be just a lifter gone bad? should I start tearing the engine down? I recently drained the oil and put 2 cans of STP and 20-50 oil to see if that would solve any hydralic noise.

 

did the oil change help? risolone is a hell of a product for a stuck lifter but from what u say im thinking cracked flywheel. hows ur oil pressure hot and idleing? and water in oil?

 

If I had something sticking I would leave out the syrup for sure. Last STP I used was 45 years ago in a 1953 Chevy PU that got 40 miles to a quart of engine oil and would roll on level ground in first gear if there was 5 MPH wind gusts.

 

lifter ticks arent uncommon. Id pour a quart of marvel mystery oil in it,run 1k miles and do a oil change. Should help,if anything run 10-30 oil if your running 5 30. sometimes it helps quiet down a noisy lifter.