First I have to explain why I removed the intake manifold on my Sierra. I've had a RX catch can installed for about 6 months now. I decided the other day I was going to try to clean up the hose installation for the catch can. I purchased some expandable braided sleeving and shrink fit tubing in an effort to make the hoses look a little more factory. While trying to remove the hose that goes from the catch can to the intake manifold I broke the plastic elbow off the comes out of the intake manifold. Needless to say I was extremely [censored] that I did this as I should know better then to pull on a hose like that. After doing some research at the dealer, this elbow that comes out of the intake manifold is not a replaceable item. It's basically part of the intake manifold. I thought about trying to repair the elbow but didn't like that idea. I wanted it done right and the only way I knew how to fix it was to replace the entire manifold. Cost me about $160 shipped for a new one.
Replacing the intake manifold didn't look too bad. Of course this theory got shot down as I started to remove the cover that goes over the intake manifold. This cover really doesn't service much purpose other then to provide holes for various plastic snap-in fittings that hold an electrical harness down. These connectors are barbed so they go in easily but don't come out with out a fight. The worst ones were behind the intake that are against the firewall. Once I finally got everything out of the way I could then remove the intake manifold along with this cover.
I have about 30,000 miles on my truck when I did this. The catch can has been on for the last 9,000 miles and recently added the RX clean side separator after find oil in my intake tube (http://www.gm-trucks.com/forums/topic/168584-oil-in-intake-tubeanyone-else-check-theirs/)
I tried to take the best pics I could of the intake valves but it's tricky to get good lighting. They all appeared to have the same amount of carbon build up on them. I didn't think there would be this much on them. Assuming the catch can prevents majority of the crankcase vapors from getting back into the motor, these deposits formed within the first 20,000 miles. I would be interested to see what these motors with no catch can looks like after 100,000 miles.
FYI this motor is direct injected.
Replacing the intake manifold didn't look too bad. Of course this theory got shot down as I started to remove the cover that goes over the intake manifold. This cover really doesn't service much purpose other then to provide holes for various plastic snap-in fittings that hold an electrical harness down. These connectors are barbed so they go in easily but don't come out with out a fight. The worst ones were behind the intake that are against the firewall. Once I finally got everything out of the way I could then remove the intake manifold along with this cover.
I have about 30,000 miles on my truck when I did this. The catch can has been on for the last 9,000 miles and recently added the RX clean side separator after find oil in my intake tube (http://www.gm-trucks.com/forums/topic/168584-oil-in-intake-tubeanyone-else-check-theirs/)
I tried to take the best pics I could of the intake valves but it's tricky to get good lighting. They all appeared to have the same amount of carbon build up on them. I didn't think there would be this much on them. Assuming the catch can prevents majority of the crankcase vapors from getting back into the motor, these deposits formed within the first 20,000 miles. I would be interested to see what these motors with no catch can looks like after 100,000 miles.
FYI this motor is direct injected.