[crg5990]

So to explain this as best as I can this may be a bit long but the tl;dr is that on a cold startup there is a loud knocking/tapping and after just 30 seconds or so of driving it essentially disappears. Very faint on warm startups.

Video https://youtu.be/mAEZF9Gdp40

Okay so a few weeks ago I noticed a faint tapping on cold startups that disappeared after warming up. Over the weeks the noise has gotten louder and lasted longer to the point now that it is more like a knock, and will not go away idling in park after a startup at all. Now once the truck is warmed up and I drive for only a few seconds, it will suddenly and drastically decrease in volume. The noise is still there but very faint. The noise will not be as loud on a warm startup.

Other symptoms the truck has which may or may not be related:

- low oil pressure (flickering warning light) in drive while at a stop, but otherwise normal
- eats oil very slowly (about a quart a month)
- evap system code

From the research I've done I'm thinking it could be a cracked exhaust manifold that's getting worse, but I can't find any videos of that to compare to. Worst case is its a rod or valve but I can't be sure (paranoid about this cause I've had this happen to my other car which is why I got the truck). Also wondering if it could be the timing chain, or a split head gasket. Again I haven't found any videos of those things to compare to.

Any help would be appreciated, especially from anyone that's had this noise from their truck. Really hoping the motor isn't going on me :/

 

[Smccarty3]

If your burning oil, you have more than just manifold problems. Just my back yard mechanic opinion. I agree they may be cracked, it's very common, but I think you need to take it to a garage and get it checked out, before you do some permanent damage. I'm pretty sure mine were cracked on my 06 when I traded it in and never used a drop between oil changes at 110k.

 

[Johaun]

To me that sounds like build up is preventing the timing chain tensioner from working properly. I would start by changing the oil with a new filter. Run it for a good 30 minute round trip putting your foot into it every once in a while. Then change the oil and filter again while the engine is hot. You may be surprised what comes out.

Sent from my HTC One M9 using Tapatalk

 

[Walrus]

That could be some badly cracked manifolds.

 

[crg5990]

Well as an update I guess, the motor crapped out on me this Sunday. Cruise control on at 70 and accelerated to pass, lasted about a second and lost power and the truck shut off (electronics stayed on). Absolutely no warning and no sounds from the motor when it happened. I've tried starting it about 50 times since and it hasn't started, only slow cranked. So far I've checked the battery voltage, pulled the plugs, valve covers, and drained the oil. Outcome so far is

- 12v and 800cca from the battery so it's fine
- oil on 2 plugs
- metal dust in the heads
- metal dust and small (~1mm) pieces in the drained oil
- motor will not rotate via wrench on crank pulley bolt

Since I can only work on it in the street at my house it will be going to a shop to have the bottom end pulled apart as well as the timing covers to see if it skipped timing. More than likely looking like it needs a motor.

If anyone's got a good source for remanufactured or low miles used motors for these trucks that'd be cool. That's going to be cheaper for me than getting another truck