94 coolant leak and more

[1slow94]

Ok i noticed today that my explorer was leaking coolant but its not coming from the water pump or radiator both new and done right it is coming from the front of the motor that much i know could it be coming from anywhere else? 2. when im driving it there is this rattle coming from either the front or under the drivers side and it only happens when the motor is under a load it sounds like spark knock but not sure it is a metal rattle and its loud if i shift in to neutral when driving it stops but as soon as u put it in drive it starts back 3. the oil pressure gauge goes from low to high then stays low unless you rev the engine it goes up then back down but now it is reading normal what could the issue with that be? it doesnt knock or run funny it runs great for a 94 with 200,000 miles on it and it is 2wd with a auto trans and a 4.0 v6

 

[Anime]

The coolant leak could be a number of things, either loose water pump bolts or a bad gasket, the engine block freeze plugs, block drain plug, perhaps even a cracked head or head gasket that allows a slight leak to the outside. Don't forget hoses and clamps as well. I had a leak that just came from the lower hose because the regular screw-type clamps don't maintain constant clamping force around the hose at all temps. Snug the clamps down and/or get constant tension clamps and problem solved. I've also found the new Prestone and similar coolants eat away at the water pump gasket, switching to G-05 coolant (Zerex) like in the new Fords has seemed to fix it.

The rattle might just be the catalytic converter heat shields. Look under the passenger side with the engine cold and see if they wobble or rattle. Fix is either remove them or re-attach with big hose clamps if that's easier. You can also string multiple smaller hose clamps together to make longer ones if you can't find the big ones, but Lowe's/Home Depot and hardware stores usually have really large ones in the plumbing dept.

If it's more of an in-engine rattle it might be either the famous 4.0L rocker issue (worn rocker arms) or a bad lifter. Only fix for that is taking the top end apart and putting in new rockers and/or the bad lifter. Mine did have some serious knock under load from dirty fuel injectors though, so some fuel injector cleaner and using brand name top tier gas (Shell, Chevron, etc.) with detergents can sometimes fix it over a period of days/weeks.