I recently bought a 2012 Colorado, Automatic, 3.7L I5 with only 37.8k miles on it. Same as all used vehicles that I buy, I did the following almost immediately:
-Spark plugs
-Belt and Tensioner
-Air Filter
-Cleaned MAF and TB
When changing my plugs, the rear-most plug (Near the firewall) was fairly coated in oil on the plug threads. My guess (I hope) is this is just oil seeping around the valve cover gasket.
Also, and this is the most concerning for me - I am getting a VVT/Timing Chain rattle on cold starts. It only rattles until oil pressure builds up, then it goes away.
I am also getting what I believe is valve squeal for about 2-3 minutes after cold starts, which isn't a good sound. It's a slight squeaking that increases with throttle that didn't go away when I changed the belt/tensioner.
It's at 42.5k miles now - Hoping that it doesn't need a new head. Any insights would be great.
-Spark plugs
-Belt and Tensioner
-Air Filter
-Cleaned MAF and TB
When changing my plugs, the rear-most plug (Near the firewall) was fairly coated in oil on the plug threads. My guess (I hope) is this is just oil seeping around the valve cover gasket.
Also, and this is the most concerning for me - I am getting a VVT/Timing Chain rattle on cold starts. It only rattles until oil pressure builds up, then it goes away.
I am also getting what I believe is valve squeal for about 2-3 minutes after cold starts, which isn't a good sound. It's a slight squeaking that increases with throttle that didn't go away when I changed the belt/tensioner.
It's at 42.5k miles now - Hoping that it doesn't need a new head. Any insights would be great.
