Well since I was doing the t-stat and requisite coolant today, I figured it'd be a good time to clean the intake, and change out the spark plugs. My oil life indicator was around 25%.
Started with doing the intake cleaning. I disconnected one of the hoses attached to the intake manifold that runs to the solenoid on the intake manifold. I sprayed GM Cleenz into the hose as fast as I could spray it out of the can. I would then reattach the hose, rev the engine a bit to make sure the engine sucked it all through, and repeated a few times. I let it sit for a while to let it sit and dissolve a bit.
Then started up the car, and sprayed some GM Cleenz through out one more time, then let it idle for a bit, and rev it a little to make sure I cleared it all through. I figured at this point, I've sprayed away any dirty stuff, and sucked through any remaining solvent.
I then started draining the oil since it was hot, and I wanted the block to cool more before dumping the coolant. And the oil could drain while I completed the intake cleaning. I Put on a Fumoto oil valve a while back so it's a breeze now. I put a clear hose on it, and into an old oil jug from the last oil change. I used some compressed air to clean off the plastic cover and sound dampening cover just to keep from getting dust/debris into the oil filler hole. And I was doing the spark plugs anyways, so the entire top of the engine got cleaned off.
I then disconnected the rubber coupler between the cold side intercooler pipe, and the throttle body, and cleaned it out. Surprisingly there was what looked like condensation had been in there at some point, and that there was a brownish powder residue left over from the evaporation of the condensation. Not rust though as it was not magnetic at all. No oil to be found in the tube. I wiped out the inside of the throttle body area with a rag sprayed with some GM Cleenz, some light carbon deposits were seen.
Then reassembled the intake, but then started the spark plugs. Disassembled the top . . . pretty straight forward. Blew compressed air into the tops of the heads before removing the spark plugs. Did one spark plug at a time. Torqued to 20 ft lbs with a dab of 5w-30 on the threads.
I then disassembled the wiper blades. Just a tip, I used the smallest 3 jaw puller set that I had. Worked like a charm compared to the horror stories I've read about how hard the are to get off. Mine had some grease between the threaded stud from the motor and the wiper arm. But during reassembly, I put some extra anti-seize.
I then drained the radiator from the petcock. Then disconnected all the electrical connections at the back of the engine block near the t-stat. The hoses were far more difficult. There are 2 hoses coming off the t-stat housing. I was only able to remove the smaller one due to the orientation of the spring clamp on the larger tube. Luckily I had a stubby 10mm wrench that I could get onto the back side t-stat housing bolt. Trying to get a socket onto it pretty chewed up the back of my right hand. The front bolt is no issue.
The old t-stat had no visible problems with the gaskets, but the centre brass? portion was severely discolored, and almost appeared to be corroded. The coolant was definitely not in its prime either. It was reddish/pink/brown and had deposits in it. The fresh dexcool was bright neon orange.
Put the heater core valves into the 2 tubes. The one above the engine block, and the one coming off the top of the radiator.
Reassembled everything. Filled up the expansion tank with distilled water. Ran it through the car with the expansion tank elevated, and with the hose in front of the block alternately clamped and not clamped. I found this was very effective at getting air out of pockets. For example before doing a procedure like this, the coolant temp would easily climb over 100* C. How high? I didn't care to find out. But after a few repetitions, the temps dropped to about 88-90* C.
I filled and dumped with distilled water twice. Then started mixing in some Prestone Dexcool. I'd pour about a quart in first, then a quart of distilled water. Run the car a bit, the level would drop, and repeat.
Haven't driven it much since. But over about a 30 minute drive, the coolant temps were a stable 88-91* C.
