I have a new to me 2005 Surburban 5.3 with 310,000 miles on it. It had low oil pressure (18 psi at cold idle), so I dropped the oil pan to replace the oil pickup o-ring. Then I thought "18 psi is really low", it might be a good idea to do the oil pump (high volume) while the pan is off. The water pump is making noise anyway." So, tonight I pulled off the crankshaft pulley, removed the timing cover and took off the oil pump. The timing chain has some slack and its staring me right in the face. If its still in good shape, I'll leave it alone. If its about used up, I should toss one in there while I have the cover off. What's the wear limit on the Vortec 5.3 chains?

Thanks!

 

While the cover is off, change the chain and gears anyway since there is play in it.

 

That was my thought as well. Thanks!