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GM 3.6 VVT

ak diesel driver

ak diesel driver

6.5 driver
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So I picked up an 08 GMC Acadia yesterday. The guy selling it said it had a blown engine but it still ran and drove. So I went and looked at it, body is in decent shape. When it was started it knocked pretty good and then quieted down. When you put the engine under load it would knock but not near as loud as when it first started. To me it doesn't sound quite like a bearing knock. So I did a bunch of research and discovered that it could be the phaser in conjunction with some chain stretch making the noise. So the first thing I'm going to do is pull the oil filter and cut it open and look for debris.
Anyone have much experience with this engine?
 
Is that a diesel ?
Nice looking rig. My friend Bob has one. His is an inline 6 cylinder. I think its a six. His was throwing a code about misfire. After several mechanics, He did some deep searching and found some guy that was very familiar with working on them. He said if You get a code for a misfire, check the battery. His battery was less than two years old. It passed the draw down test. He told the guys at the parts store, put a new one in, if it dont fix the problem, I’ll buy the new one and keep the old one. Ok, stuck in the new battery and it has run real well ever since.
Another problem, could not get it out of park. He was at the post office and called Me. Told Him sounds like the solenoid or whatever it is that control the function between the brake pedal and the shifter was not properly functioning. Might be a bad ground. I did not know what else to tell Him so I told him to put his code reader on it, see if anything come up. He did, nothing for codes but then He mashes the braking pedal, pulls it right into gear. He calls me back and tells Me. I told him it is a bad ground for sure. The code reader patched a grounding circuit.
He took it to a shop, they tore apart the council and found a bad ground connection. I think it was in the council. Might have been under the dash.
 
Ive worked on a few of those. They are known for timing chain issues. Usually if the chains stretched it will set timing codes. If its making noise and actual to desired VVT is correct on all 4 cams then it more than likely needs an engine. If the actual VVT is off from desired then its possibly just a chain issue. The timing covers are fun to remove on those.
 
I don’t know that engine, but I do know every single time GM has done VVT with cylinder shut down- it wears out the engines faster. Just VVT by itself is a good thing usually.
If you find out it is a combo one, get the cylinder kill turned off.
 
I once thought a 5.7, 350 V8 in a 1990 Chevy had a lifter problem. Back off the lifter slightly, tick would go away momentarily then come right back. Tighten it slightly, same thing. New cam, sprocket/chain, lifters, push rods and rockers. Fired it up, same problem. Dropped the pan and no.7 and 8 rod caps. Sure enough, spun and bad bearings.
If I would have first off pulled a plug wire at a time, I would have known it was a rod, but, it just sounded too much like a bad lifter.
By screwing on the rocker adjuster nuts, it was momentarily dropping the compression until the lifter gained back again.
 
Send that oil for analysis .
On the filter: Is that magnetic?

How bad is cost and labor on just doing bearings? Anything with a knock I have learned to just rip it open unless that cost is high. Because bearings are usually what gets wiped out first and are low cost & primary wear item- do them and inspect for anything slightly damaged before it becomes majorly damaged.

My glowplug ruined my piston. If I kept going it might have damaged head, valve, turbo, cylinder wall. Just don’t get into analysis paralysis like I did. Haha
 
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