Cold Engine Noise

[Airman68]

I have a 2008 Yukon XL with a 5.3L. It currently has 210k miles. I have had it since 190k and have the afm disabled. In the morning when the engine is cold, it almost sounds like a really quiet diesel engine. Just a slight lifter noise? I cant say when it started. Heck it's probably been doing it for a while. Once the engine warms up, it's almost non-existent. Just curious what everybody thinks. This along with the common oil leak issues is getting me to consider looking for a newer rig. I'm just curious how serious this is.

 

[Geotrash]

I have a 2008 Yukon XL with a 5.3L. It currently has 210k miles. I have had it since 190k and have the afm disabled. In the morning when the engine is cold, it almost sounds like a really quiet diesel engine. Just a slight lifter noise? I cant say when it started. Heck it's probably been doing it for a while. Once the engine warms up, it's almost non-existent. Just curious what everybody thinks. This along with the common oil leak issues is getting me to consider looking for a newer rig. I'm just curious how serious this is.

Piston slap when cold is common on these. Both of my 6.2's do it. If you can post a video here (upload to YouTube and post the link), we can help you determine what it is.

 

[Airman68]

Ok, thanks. I've had trouble in the past trying to post stuff, but I'll try again. I'll get some video this weekend during the day. Too dark before work. Still trying to adjust to this time change. It's getting the best of me this year.

 

[ReaperHWK]

Could also be a small exhaust leak. I have one on my f150 and you only hear it at cold startup and it goes away after the metal expands and fills the gap. Thinking it’s my manifolds.

 

[strutaeng]

Piston slap or manifolds as was mentioned. Check your manifold bolts as they are known to break. At your mileage, you may even consider getting the manifold bolts replaced as preventative maintenance.

I don't think you would do anything about piston slap TBH. My 5.3 does it consistently, but not my 6.0s. It's probably due to very small tolenaces of the piston/cylinder bores.

 

[Marky Dissod]

I've got this odd cold start problem, where the initial RpMs could easily exceed 2000 for the first five to ten seconds,
which would make the cold piston slap worse.
Not so much a fix, as a workaround:
I floor it just before cranking for 3 or 4 seconds. Flooring it during cranking is clear flood mode.
This gives the motor oil a head start.
Sometimes my RpMs are still a bit too high, but the piston slap is nearly nonexistent this way.

 

[Airman68]

Could also be a small exhaust leak. I have one on my f150 and you only hear it at cold startup and it goes away after the metal expands and fills the gap. Thinking it’s my manifolds.

I am familiar with the exhaust sound, this is not it. I replaced my driver side manifold already. The other one has a broken bolt, but it is not making noise yet. The piston slap theory makes sense.

 

[Joseph Garcia]

I am familiar with the exhaust sound, this is not it. I replaced my driver side manifold already. The other one has a broken bolt, but it is not making noise yet. The piston slap theory makes sense.

How old is your oil? In my previous Yukon (RIP), when the oil approached 3000 miles (my oil change interval), it would tap a bit on cold startup. As soon as I replaced the oil, it was gone for the next 2500+ miles.

 

[Airman68]

Interesting. It is just under 3000 now, due to be changed. I'll have to see if that helps. I can say, my oil pressure is really good. 30-40 at idle.