Before I pull this 5.3 engine I decided to diagnose the problem in case I could save the motor. I did a compression test and got about 145 to 165 lbs of pressure on 3 rotations using the starter. I was able to get 200/210 on 5+ turns of the engine on all cylinders. There is a moderately loud tap on the pass side either 2 or 4 and I assume it's a lifter. Number 3 cylinder plug was caked in oil/carbon and was shocked it was firing. I replaced the plug. I pulled the valve covers and found the inside extraordinary clean. Turns out it has the Castech heads. I just bought the vehicle at a heavy discount. 2005 avalanche 210K.

Three questions

So would an engine with compression numbers like this have bad rings? I have to assume the cylinder with the fouled plug would be the oil consumer. The ticking is loud but on the other side of the engine.

This engine makes enough smoke to lead 200 fighters into battle. Can coolant produce this much smoke? I checked the oil and was 1.5 qts low so I filled it up and it got worse.

I will probably see the issues once I pull the heads. I'll be able to inspect the cylinders and lifters. Experience is the best teacher so is there anything specific I should look for? I have another running 03 5.3 motor with 330k miles (leaking rear seal). I would like to be at or under 1k on repair but parts are hi.

Thanks
Brian

 

I'd do a proper leak down test with all plugs removed. Add an oz. or so of motor oil to each cylinder with a small funnel. Then do the leak-down test. All cylinders should be within 15 percent of the lowest reading. If not the cylinders/rings are worn out out, a piston is damaged or you have valve-train problems. Are you having to add coolant to the vehicle? If so, its likely a head-gasket leak.I. it burn lots of oil then the same. The motor will need re-manufacturing.to obtain optimal performance without all of these issues.