Intake manifold gasket replacement

[MountainManJoe]

I had a slow coolant leak, which eventually turned into a heavy coolant leak, until I had Niagara Falls underneath. First I ruled out the radiator, hoses, heaters etc. It was coming from the front driver side corner (cylinder #1), drenching my front axle, but also flowing backwards along the valve cover and down the back of the engine. I started at the top and started removing stuff until I could see exactly where it was coming from. After removing the upper intake plenum, I determined it was likely the intake manifold, and very unlikely to be the cylinder head.

So I purchased a Felpro gasket kit for $100. The kit includes a metal manifold gasket with rubber seals, and also seals for the upper intake (plenum), throttle body, valve covers and grommets, distributor, a bunch of o-rings and a tube of RTV. I followed the procedure in my Hanes manual, but it wasn't necessary, as it's pretty straightforward. You have a remove quite a bit of stuff to access the manifold... fan shroud, serp belt, intake, throttle, coolant hoses, sensor wires, alternator + bracket, AC + power steering pump (just moved out of the way). Dog house, distributor, ignition coil, fuel injection spider, etc... No steps were particularly difficult, and I didn't need any special tools, but it just takes a long time to disassemble, clean everything, and then reassemble. I spent a lot of time removing the thick accumulated grime. (I discovered that the valve covers actually have "Vortec" stamped into them LOL). The manifold has all kinds of little nooks and crannies for it to get into. I curse Gm for many things, but they did a good job making each sensor connector different.

The distributor was stupid easy. Just make sure you position the crankshaft at top dead center (TDC) (procedure may vary according to your engine model). To do so, put a large socket + breaker bar/ratchet on the vibration damper and turn clockwise. There are two grooves on the rim. Turn until the second mark lines up with the timing notch on the front of the block. Check to make sure the distributor rotor points to the #1 contact. The #1 position should have an arrow with a "9". If it is 180 degrees out, turn the crankshaft another full turn. Now you can disassemble without worries or marking anything. When reassembling, the housing only goes on one way, and then just make sure when dropping in the rotor that it lines up with the "9". My housing and plug wires were all labelled with cylinder numbers.

The gasket failed @ 160,000 miles (260,000 km). I'm unsure if it was original.

And now, what everyone's been waiting for, the pics...

[MountainManJoe]

And some close-ups of the manifold surface. (click to enlarge)

[LiftedAWDAstro]

That's a job I hope to not have to do. At least it's documented here pretty well!