Hello all, i have decided to dive into the head gasket replacement myself. I didn't have much of a choice as it started waterfalling coolant out the rear passenger side of the engine. The below pictures are for reference of anyone else doing this project. I was surprised to see the cross hatches still in the cylinder walls. Also, I think the last shop didn't put the gaskets in the front and rear of the valley gasket, which led to some oil loss. Any Tips while I have everything out? Anyone with eagle eyes see any issues?

Engine has 210,000 Miles, was interesting to still have cross hatches visible in the cylinders



Amazing how clean this was compared to valve rockers

The paint had disintigrated off the top of the valley gasket, I also think the last shop did not put the rubber gaskets at the front and rear and that caused some of the sludge issues

Could not find a spanner wrench/pully holder kit, so i used an oil filter removal tool and a cresent wrench, Yes i did bank my knuckles on the alternator.

Looks about par ?

 

I'm also currently in the process of a top-end tear down on my '99 D1. I also removed the front cover to check the wear on the oil pump and replace the timing chain. You might also check for wear on your hydraulic lifters and valve stems. The repair manual should have tolerances in it and you can use calipers and feeler gauges to make sure everything is in spec. Look for uneven wear on all moving parts, might pull out the cam as well and look for excessive wear. Clean everything well before reassembly. Get off all the old gaskets and make sure you have smooth mating surfaces. Go have the heads resurfaced at a shop.

 

If still original, cam and lifters will likely need replacing. RPI Engineering has good write ups, including how to read the wear patterns on the cam and lifters, and how to judge engine condition by looking in the oil fill cap. Consider rocker arms and shafts too, if you have the time and money. These all can be done later with the heads installed if you don't want to do it now. If you change the cam you should also change the chain, even gears. Depends how much driving you plan to do I guess. Personally, my trucks are my hobby and I like renewing worn parts, even if it doesn't make complete economic sense. It is really awesome that all these parts are easy to get, and not too expensive (compared to a tank full of gas).

Valley end seals also seal the crankcase/PCV system (crankcase should be a bit negative pressure) so could throw off the air/fuel equation a bit. Hopefully you get some improvement when you get it all sealed up properly.