anti-freeze / coolant

Was just check out my truck this morning and notice wet spot under the truck, investigated and found anti freeze / coolant slow drip looks like it coming from the head gasket on the back drivers side. This motor was replaces 2 yrs ago with an amg unit. Any suggestions ? It Hasn't leaked anything before. Should I pull the head and replace, or throw some stop leak in. I topped up the coolant for now and going to watch carfuly. I just finished installing the lift pump relay from Kennedy yesterday, working fine. Was hopeing for a few Kl of worry free driving , Damn it all.

Well, got some good new, seems that when I loosed the glow controller, which was mounted on a stud that holds down a plate , it too loosened off and I didn't notice it at the time, so I removed and retighteded it moved the controler to diffrent stud and it stopped. ( sometimes we are lucky ). Always chech the simple things first DUH !!!! To antone who is installing the Kennedy lift pump control : Note if your block is same as mine there is no room at the back of the block to turn in the brass 'T' fitting in without interferance of the left head. I found out this after an Hr. of buggering around, so I remover a plug in the valley below the intack and ahead of the fuel filter, and with some cursing got the new sender in place, after this was snap routiing wires. I was running my lift pump ' HOT' through a switch to make it work and to see if this was my problem before I orderd the kit. The Oil switch was not even a year old. Hope to not have any more problems for awhile now. want new set of pipes and get that CAT gone.