Timing chain for a 2008 Silverado

[John Bush]

When should a timing chain be replaced?

The truck is at 138,000 miles.

[Jsdirt]

Which engine? If it's the 5.3, you're going to be replacing the engine long before the chain wears out. You're right at the mileage for cam bearing failure, and/or lifter failure.

 

The 4.8 seems to be pretty good, and the 6.0, & 6.2 are hit or miss, but better than the 5.3.

Edited August 16, 2019 by Jsdirt

[CamGTP]

If you asked me, never.

 

I've seen brand new timing chains with the same amount of slack as the old chain.

[Jsdirt]

6 minutes ago, CamGTP said:

If you asked me, never.

 

I've seen brand new timing chains with the same amount of slack as the old chain.

The guides fail before the chains these days. Ford is famous for that one across their engine platforms. Plenty of these trucks have jumped time and smashed valves due to worn guides, too. 

 

More often, the cam will bind in screwed up cam bearings, and shear the roll pin in the cam gear, also resulting in smashed valves. 

 

GM really did us a solid building these ones ... (*NOT*).