replace it
Water can not leak from the rear main seal, only oil. Most likely there is a leaking freeze plug near the rear main seal dripping water onto it.
There are 6 altogether. 4 on the sides and 2 in the rear. They are hard to install and keep from leaking so I suggest you take it to a garage.
rear freeze plugs
The 2006 Chevy Trailblazer passenger side rear freeze plug is located near the back of the engine block. The freeze plug will be near the bottom of the engine block.
On the lincoln 4.6 lt engine yes you have two freeze plugs in the area of the starter, one exactly above the starter and another above but on the rear side of the block.
There are freeze plugs on the front, rear, and flywheel side.
Do you actually mean the back(rear)of the motor or the rear side? Dont maen to pry but are you SURE its a freeze plug? These motors had a real problem with the rear(usually the pass side) intake leaking coolant. Anyway if you mean the actual rear of the block you have to remove the trans. If its a freeze plug on the head depending on the room behind the head to the firewall,I think I would pull the head. Freeze plugs pry out(something like a screwdriver through the middle and pry) and are driven in. Parts place do have freeze plugs with a nut that you can toghten instead of driving a plug in.Ive never used one may be easier.
You will either have to remove the transmission are pull the engine out. It is what ever you think will be the easest for you. Then just knock the plug out, clean the hole with sand paper and drive the new one back in with a hammer and a socket that will fit in the freeze plug. Then put it all back together. There are 2 plugs in the back of the engine, replace both of them. You will see 1 plug in the center of the back of the block that is not a freeze plug, it is a cam plug do not bother that unless it is leaking engine OIL. Leave it alone.
Worst case would be a freeze plug but most likely it is a heater hose or connector where it goes through the firewall. Good luck.
Usually lower rear freeze plug on passenger side Usually lower rear freeze plug on passenger side
The hardest part of the job is GETTING TO the freeze plug. Depending on which one is leaking, sometimes you need to pull quite a bit of stuff just to get to the freeze plug. You need to be able to examine it and have clear access to the freeze plug and if it's one of the rear plugs (under the flywheel), you're only option is to pull the engine and/or transmission. Once you can get to it, just drive a screwdriver or other sharp object through the freeze plug and pry it out. Clean the block around the freeze plug then install one of the aftermarket types, preferably one that allows you to tighten a bolt to install it. You'll have trouble getting an original type freeze plug to seal if you don't have the engine block sitting on a workbench. Any time you have an engine machined, always replace the freeze plugs.
Its 35 mm