I'm terrible with P/S maintenance. I changed the original OE fluid in my '86 Grand Marquis in 2015, lol! It's still on the original P/S pump and steering box, too! Only reason it got changed was due to a blown high pressure line.
The guides fail before the chains these days. Ford is famous for that one across their engine platforms. Plenty of these trucks have jumped time and smashed valves due to worn guides, too. More often, the cam will bind in screwed up cam bearings, and shear the roll pin in the cam gear, also resulting in smashed valves. GM really did us a solid building these ones ... (*NOT*).
Jsdirt started following How well are these truck tires balanced at the factory?, Timing chain for a 2008 Silverado, 6.2l high km's misfires at idle but not when driving and and 4 others
Which engine? If it's the 5.3, you're going to be replacing the engine long before the chain wears out. You're right at the mileage for cam bearing failure, and/or lifter failure. The 4.8 seems to be pretty good, and the 6.0, & 6.2 are hit or miss, but better than the 5.3.
Best thing to do I think would be to chock the wheels, leave it running when it's making the noise, and crawl underneath to pinpoint the sound. Just putting the end of a plastic hammer handle against the oil pan, and putting the hammer end on your ear will amplify any sounds. Just want to be 100% sure it's an internal engine sound you're hearing. The way you described it would make me want to be sure there's nothing contacting the spinning flywheel. Just had a Dodge that had some rust buildup causing a similar noise. Removed the flywheel cover, scraped it all out with a long screwdriver, and it's nice and quiet now. But, since you say the noise starts with heat, that tells me it's either an oil pressure issue, or indeed the bearing, or wrist pin (wrist pin noise will be much more rapid than the cadence of a bad big-end bearing).
Higher octane isn't going to stop any misfires. Higher octane means a slower burn - when you have a high compression engine, or forced induction of any kind, or are advancing the timing farther than spec (not possible on a stock vehicle today), then you would require higher octane fuel to prevent pre-ignition, or "knock" . You'll hear spark knock at high engine loads. Letting up on the pedal a bit will make the knock stop. That's pre-ignition. Detonation will make the same sound, but it sometimes has a different cause, like glowing carbon chunks, or part of a head gasket. A blinking check engine light is a complete dead miss - not a partial miss. Should be easy to narrow down. Spark, air, fuel, compression - it's one of the 4. See if you have injector pulse on the misfiring cylinder. If you do, try swapping the injector with another good one as was already suggested. If you have 94% leak down on ANY cylinder, that's your problem! Did you mean 6% leak down? EDIT just to add, don't be fooled by a lack of injector pulse on a severely misfiring cylinder - the computer will cut injector pulse on certain vehicles if there's a severe, constant misfire. Check for pulse after a key-off event, and pay attention to it immediately after start up. It will take several seconds for the computer to cut the pulse. If any of this is above your skill level, take it to a local garage (NOT the DEALER !!!) for diagnosis. Given your symptoms, I'm betting on a vacuum leak. Either a nearby hose, or the intake gasket.
How many miles on her? Noises are one of the toughest things to diagnose over the internet ... The engine could very well be at the end of its life.These engines have ZERO tolerance to neglect. If you don't know the history of the first 50k miles, then anything is possible. The 5.3 is more known for wrist pin slop that will cause a "bad-bearing-like" sound (only a double-tap, rather than a single knock), but given that the engines are nearly the same internally, that could be your issue too. A simple .30 cent o-ring can bring these engines down fast. That o-ring is in the pickup tube to the oil pump. If you're going to drop the pan, that would be the first thing I'd check. You can also access it by removing the timing cover. Normally I'd recommend replacing the oil pump and timing chain if there's alot of miles on her, but with these engines, usually it ends up being a waste of time and money, as something else will fail down the line. A crate, or junkyard (if you can get one cheap) engine is the way to go, rather than a rebuild. If you're certain there's bearing noise, that's the route I'd take. As a last resort, you could try some 10w-30, 15w-40, or even 20w-50 engine oil - if the heavier grades make it more quiet, then it's definitely a lower end bearing, or wrist pin. if it gets louder, there could be a restriction, or partial blockage in one of the oil passageways. Got nothing to lose by trying. I've been on 10w-30 in my '07 for the past 20k miles. Since then, my oil analysis' have come back much better as far as wear metals are concerned.
Been a while since I've done one of these, but I recall just cutting those stupid ends off the hose, and just clamped it direct to the metal nipples with regular hose clamps (worm style).
Ain't that the truth, Doug! I remember yanking coil springs out of my '78 Cutlass behind my parent's shed with nothing more than basic hand tools, and a jack. Rebuilt that whole front end, control arm bushings and all. Drilled all the ball joint studs out with an electric drill, and knocked them out with a punch and hammer. Air tools were a luxury that was still 5 years out for me, then. Took me 2 weeks! Took the bus from the city which only came within 5 miles of their house - walked the rest of the way carrying that 50 lb. toolbox. I have a hard time carrying that damn thing across the shop these days, LOL.
On my '07, GM sold entire control arms for both upper and lower ball joint replacements. I just bought Moog components and installed them myself. For the uppers, it is MUCH easier to just replace the whole upper control arm. If you don't have a ball joint press, you're going to be fighting that thing for HOURS trying to get the ball joint out of the control arm. The lowers on mine were a nightmare - at the time, I had a press, but didn't have the correct adaptors. I had to improvise with junk laying around the shop, and swing a 20-pound sledge to get the stupid things out. If you don't have a press, just replace the control arms. You'll thank me later. You'd have to get a front end alignment just replacing the ball joints anyway, so it's not a big deal. Don't install cheap (as in quality - NOT price) GM junk back in it - replace the stuff with Moog. You'll thank me later on that as well.
Because they are in for repairs so often, that no matter the year model, they're always like brand new. As a side note, the new emoji list is TERRIBLE. Takes an eternity to load, and they just don't look right to me. The one I used above I got off my iMac ... but was transformed into the new one.
1,400 miles? GM had damn well better fix it, regardless of the balancing method used.
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