Hey everyone. I noticed lately that my 4.3L is making a "clicking" or "tapping" noise at idle that wasn't there a few months ago. Not loud like the "4.3l blown engine/spun bearing" videos on Youtube, but noticeable especially when I stand near the front end. Oil pressure is the same (30 idle when warm/60 on cold start/45-55 moving) and it seems to drive fine. I do notice some degree of hesitation on startup that is new, but it seems to start fine most of the time. The only real anomaly I noticed was last oil change at 120k when I noticed a minor increase in fine metallic particles on the magnetic drain plug, but I could probably explain that by very short drives over the summer without letting it warm up for a couple minutes as I normally do. There was nothing in the oil (no weird colors, no metal). Should I use thicker oil now that my truck is getting up there in miles? I use Mobil1 HM 5W-30 with no additives nowadays. I also know that I have a vacuum leak somewhere because my climate controls are not working right even after I replaced all of the hoses under the hood months ago and disabled the front axle actuator since it is no longer connected. I will post a video tomorrow in the daylight. Thanks

 

tick could be a vac leak, could be the PVC valve as well? maybe someone else will chime in.

 

First thing that came to mind when I read clicking was a possible bad spark plug wire that is arcing out which could possibly also explain the hesitation. Not sure but thats what came to mind for me. Easiest way to find that is to start your truck at night and look under the hood for and little abnormal electrical arcs.

 

With a spray bottle with water & mist the engine/electrical.

 

Might also want to look at your belt tensioner and idler pulley.

 

Thanks for the tips so far. Now I know what to check when I can look at it.

PCV Valve is new, wires/plugs/belt/tensioner are only a year old or less and I just did the cap and rotor earlier in the summer. I will need to check for vac leaks, but any recommendations on a procedure to do that? Thanks

 

go out there at night with a spray bottle and spray water around the wires while its running. if anythings arching you'll have a mini fireworks show. With that oil pressure stick with the 5w30.

 

Well to check for the vacuum lines, visually of course. Look for cracks, weather, drying out, loose, disconnected/open lines.
Another way I've used with success is brake cleaner. Let the engine idle & spray brake cleaner along the lines & at connections. Any change in the revs or way the engine idles probably means a vacuum leak as the brake cleaner gets sucked into the engine.
Probably a better way is to have someone hold the revs around 800 or so. Not too high so it isn't deafening & the fan doesn't blow brake cleaner away from intended lines.