How do you replace the water pump on a 1988 Plymouth Colt and what tools are needed?

Just basic wrenches and a long screwdriver are needed. Besides draining the coolant (remember to turn on the heater so the core drains here too) the timing belt tensioner has to be taken off the side of the engine. With the alt/wp belt still on, start to loosen the four little screws holding the wp pulley on the hub. Now remove this belt (alternator adjustment) and you can take off the pulley completely. Remove the two belt covers (upper, lower), loosen the tensioner adjustment and pivot bolts, use the screwdriver on the finger to push the tensioner off the belt against the spring and while holding it retighten the adjustment screw to hold the bearing out. This will let you slip the belt off the cam sprocket, and then let the tensioner out to the end of its travel. Now use the screwdriver pivoting on the side of the engine here to gently lever the spring end off the finger. Then the pivot and adjustment screws can be completely withdrawn, freeing the tensioner and exposing a covered pump bolt. Remove the pump bolts and the pump can now be pulled away from the block and the pipe, where it mates using an O-ring (your replacement pump will come with a new one of these a well a a gasket for the block). Carefully remove all traces of old gasket using a single-edge razor blade and some WD-40 or similar product to soften baked/stuck old gasket material. If using sealant on the new gasket (recommended, but messy) strip the mating surfaces with solvent first, if not, grease the new gasket instead. Recommend silicone sealant on the new O-ring too, but not absolutely necessary. With the gasket and O-ring in place, push the pump back on the pipe and up into position against the block, with bolts at ready to secure everything in place. Gradually tighten the bolts in crisscross fashion, and if you used sealant let it cure for a couple of hours and then tighten one more round. Put the tensioner back on the side of the engine with the two bolts' leaving them a bit loose yet, but do not try to get the spring on it first -- just put it back on as you took it off, with the spring end off and over the finger. Then, working the other way from when you disengaged the spring end, use the screwdriver to lever it gently back up and behind the tensioner finger where it should be. Then you can push the tensioner back out against the spring and tighten the adjustment bolt temporarily, enabling the loose timing belt to be slipped back on on its original position on the cam sprocket. Loosen the adjustment bolt now to let the tensioner reassert itself, and retighten the adjustment and pivot bolts. Put the lower cover back in place, which contains a timing mark (0 or T) to be matched to one on the crank pulley (just a notch) and rotate the engine using a ratchet on the center crank bolt and make sure this matches up with the cam marks (pointer on the cyl head and dot on the sprocket) ensuring the engine is still in time. If it got off a tooth loosen the tensioner bolts, push it out of the way and tighten bolt to hold again, and slip off belt and get things right -- then let tensioner back on belt, tighten, and recheck. Try to get it about the same tightness it was at the start, but not tighter. (Ideally the belt should be changed here). After everything is right rember to tighten the pivot bolt too, then replace upper cover, pump pulley and coolant and you should be ready to go. May run a bit warm until system fills completely through recovery system.