ecs and oil line adapter

how many GMC engineers does it take to screw in a light bulb??

I got two questions....I changed out my leaking oil cooler lines, but couldnt get the 'adapter' on the engine to drop down to change its gaskets...does it need to be unscrewed or something?
Second, i want to do my timing, the manual says to unplug the engine control switch...but it doesnt say where this switch is. As well, my timing marks have no numbers on them, just 3 teeth. which is the right one?

pull the right motor mount cross bolt, jack up that side a couple of inches, using an extention use a 13mm socket to rmeove both bolts... Install in reverse

What year? I can tell you on 91-93, did two of my own.

I went and found my old posting for the adapter o-ring and gasket replacement on 90-94. Should be on first page now under 90 s15 jimmy o-ring replacement, oil filter lines. I'll check back to see if it helped you.

Thanks guys, my truck is a 91 4X4. I had no trouble (well, a little) unbolting the oil cooler lines from the adapter, thats not the problem. The 'adapter' is what I want to pull out, so i can change the oring and gasket. I took out the two bolts, but the adapter wont drop out. I even grabbed it with a vice grip and tugged on it, it woulndt budge. maybe its got a vapor lock or something holding it in place. it is leaking a lot, but im still not willing to shell out $75/hr to the dealership to have them do it. thanks!

with lines on for use as a handle) wiggle it back and forth (use the old lines) until it rocks free. But really, if it wasn't leaking at that gasket you don't need to change it.

2x2 wood and hammer to break it lose, tapping it back and forth. Big O-ring and a gasket in there. Will break lose though. Fits about a inch up inside the block. Hope that helps Check the O-ring posting out too.