P0014, No Oil, Runs Fine but Bottom End Knocking

[demonspeed]

The facts rather than an elaborate story:

2007 TrailBlazer 4WD 4.2 I6 154k miles; owned since 35k miles. Came here from the "other" site -- glad to have found where all the techie people ended up!!!

5k mile oil changes; 5w30 conventional until around 120k at which time I switched to Valvoline Max Life High Mileage 5w30. Always use ACDelco PF61 filter.

Recently down on power with rough idle. Cleaned MAF and throttle body, but no change.

Later throws two codes: both P0014. Change CPAS (did not appear clogged) and clear codes. Drove 150 miles. No change in power/rough idle; engine light back on.

Pass a truck on highway and then notice erratic oil pressure between 0 and 40psi. Hear slight knock. Check oil and nothing showing on dipstick. 8k miles since last oil change (longest I’ve ever gone – woops!).

Drained oil… only about a quart from the pan (normal amount in filter). No oil leaks anywhere. No debris in what oil was drained.

Changed filter and added oil. Also changed plugs with ACDelco 41-103 (had last changed them at 99k miles). Below are plugs 1-6 (L-R):


Horrible idle at first but then smoothed out. However, slight knocking noticed; got louder. Videos:
https://www.youtube.com/watch?v=B7sg1JJIJIw
https://www.youtube.com/watch?v=ZwqhCxuCWu4

Took it for a drive of varying RPM. Idled great and power was back; however, knock is worse/louder. Engine light back, but codes are yet again two of P0014. Videos:
https://www.youtube.com/watch?v=du9Qy0MvDcU
https://www.youtube.com/watch?v=NBFg4BgbI98

I’ve never had oil consumption issues between oil changes before, so I surmise that the 8k mile oil change interval is merely a coincidence to this happening (that is, I cannot believe 3k extra miles would have caused such a drastic problem).

I poked around with a stethoscope and hear nothing out of the ordinary up top. I couldn't really get to the short block to hear with the stethoscope.

This morning... time for a cold start. Silence! At least for about a minute... Power and idle still fine -- no engine lights as of yet. Video:
https://www.youtube.com/watch?v=_mQxWyN9zHM

Questions:
Where the f*(k did that oil go?!
What does the knock sound like?
What is up with the perpetual P0014 codes – and why are they doubled up?
What do I do from here?

 

[gmac310]

Not sure where your oil went but that knock sounds exactly like my engine earlier this year. Sounds like lower end rod knock or bearing knock. At first I was surprised that your engine was running it was that quiet. At first mine wouldn't make noise except a certain RPM range then made it all the time. Cold start sounded great until oil thinned out too. Hate to say it but it sounds like damage has all ready been done, I had to swap motors.

 

[Mooseman]

I have to agree. Definitely sounds like a rod knock. Since it's louder when you take the cam under the truck pretty much confirms it. The oil loss is irrelevant now. It's done.

P0014 could be related to the oil issues since it uses oil pressure to control the cam phaser. It's doubled because one is the actual code and the other is pending. It usually like that for most codes when it hasn't been fixed.

 

[demonspeed]

Sorry for the delay in response -- I wasn't receiving emails that anyone had replied for some reason.

Anyway, thanks for the opinions. I have done a ton of reading on this, and it appears it's not uncommon. I had always been under the impression the Atlas was a bulletproof engine... *shrug*

I found an engine with 119k for $1350 with a 6 month warranty, so that might go in to replace this one. On the other hand, I don't feel like exerting the time and energy to do it The truck is solid, no rust, clean, and OCD maintained (except this one time!) with all records since 35k miles. Worse, I was surprised how low the values on these things are. Just a shame to let the thing go, but I don't even know if it's worth putting the used engine in.

 

[Sparky]

Atlas is really strong, yeah, but any engine isn't going to like being run on low oil. Now what happened to the oil I can't tell you. And like anything there is are always some that just don't make it. I've seen a lot of these with over 200k.

You know the history and condition of the rest of the truck. I'd say it is worth it. I always feel it is a gamble buying a used vehicle as you don't really know its history.

 

[Blckshdw]

Buddy of mine had a similar issue with vanishing oil, and no dripping in the driveway to help pinpoint where it was getting out of. Turned out to be his rear main seal leaking.

 

[BlazingTrails]

And this Gentlemen is why we check our oil on a regular basis.

 

[smokey262]

+1 on the big end rod knock.

The only time I heard that in a vehicle of mine was about 30 years ago when I bought a car without hearing it run first. It was from an old girlfriend of a friend of mine. All of the spark plug wires were cut up and I bought it cheap. Put in new wires and fired it up. Wow, just like yours, maybe worse.

Tore the engine down and could not believe how sloppy the rods fit on the crank. Not just bearings either, the actual inside diameters of the rods were toast.

Learned an important life lesson that time. Never ever buy something with a motor without hearing it run first, regardless of price. Unless of course you know its already junk.

Good luck

 

[gmcman]

Remove one coil lead at a time and see if the knock goes away. Sure sounds like a rod but don't dismiss a flex plate bolt at the torque converter. Just something to check before you tear it apart.

My cell didn't upload the last 2 videos so I just heard them....ouch. I don't think thats a flexplate.

My S5 has been quirky lately and sometimes it's hard to even see all the text without it zooming in and out.

Man that stinks. If the truck is sound, I think it's worth another motor albeit labor intensive being a 4x4.

 

[RedRocketZ28]

I was with gmcman for a minute as well. Sounded similar to a buddies Trans Am that the flexplate bolts backed out on. However, that wouldn't really make sense since it was quiet on a cold start. Definitely something worth checking though. Also, if you took out a bearing then there would definitely be shavings in the oil.

 

[gmcman]

There likely wouldn't be shavings everywhere, but maybe some gold glitter. Only 1 quart in the pan is bad news for sure and it's not that loud when cold.

That's a bummer man, as loud as it is you probably spun a bearing so I would definitely not drive it anymore.