Loud *clank* sound from engine - 2007 Tahoe 5.3L

[techbiker]

Ryan- Have you been under the engine when the sound happened? Do this at your own risk, but if the sound is loudest at the oil pan then you can be fairly sure it's a problem in your bottom end.

Best to rule out rod knock now before you rack up any more mileage. The longer you run the motor with internal problems, the more damage you will typically cause.

 

[iamdub]

In that video, I'm not seeing anything on the accessory drive jump or move when the sound is made.

When did this start? Was it after any particular event that you can recall? Only does it at idle?

 

[hound_dog]

Thank you techbiker for the warning, I'm minimizing use.

I did remove the AC compressor belt today (had to do it during lunch). The outside temp was about 65 so much warmer than it has been for the first start up of the day.
I started it up and there was NO clank sound for the 5 minutes that I ran it.
I'm going to let it sit and start it up before 8am when it is at the coldest. We'll see what happens.

 

[hound_dog]

In that video, I'm not seeing anything on the accessory drive jump or move when the sound is made.

When did this start? Was it after any particular event that you can recall? Only does it at idle?

The clank started the day I posted (Friday Dec 29). The engine has had a somewhat rough idle for a couple months. I attributed it to a broken engine mount (driver side) which was replaced on 12/5/17. Also at that time an oil leak was fixed by replacing the Oil Pressure Sending unit AND the Engine Cylinder Deactivation Solenoid. The oil leak was solved by that work.

 

[HiHoeSilver]

Thank you techbiker for the warning, I'm minimizing use.

I did remove the AC compressor belt today (had to do it during lunch). The outside temp was about 65 so much warmer than it has been for the first start up of the day.
I started it up and there was NO clank sound for the 5 minutes that I ran it.
I'm going to let it sit and start it up before 8am when it is at the coldest. We'll see what happens.

Maybe it's just the damn compressor?!

 

[hound_dog]

Yes, I'm hoping that's it.
But I want a repeatable test (it only happens when cold) before I celebrate and get that fixed.

 

[hound_dog]

Alright so I started the engine with the AC belt removed. The temperature was a bit over 50 degrees. After 2 minutes, it clank'd. Well crap.
So I put the belt back on and called the shop for an appointment to look at it. I'll update the thread when I know more.

 

[kbuskill]

Just out of curiosity... did you have both belts removed or just the A/C belt?

 

[hound_dog]

Just the AC belt. I of course needed to loosen the serpentine belt to get the AC belt off.

 

[Dillon2222]

while watching the video at about the time the cluck sound is made, you can see the water pump pulley stop for a brief moment. might want to look into your water pump being replaced if it is still the factory one. just letting you know what i saw during the video. let me know if replacing the water pump works for ya