Coolant leak at rear of block?

'88 Renix: I have a slow drip coming from the middle of the block at the very rear (slightly to driver's side). My manual shows diagrams of the plumbing for the 4 cylinder and v6, but I can't for the life of me find a good diagram of the old I6 system. I've tried to find the leak, but everything is so gunked up and it's in a very awkward area. It drips onto the downpipe, then the ground. What is in this location that could be leaking? Hope it's not a head gasket (high oil pressure too if that means anything...)

Thanks for any help

First thing to check is the frost plugs on the block and head.

There is one in the head, there are 2 in the back of the block behind the bellhousing, One of them is 2", the other is 2 9/16". The other three are along the side just under the intake manifold.

(5) 2" Plugs
(1) 2 9/64" Plug
(2) 1" Plugs

Tim_MN said:

First thing to check is the frost plugs on the block and head.

There is one in the head, there are 2 in the back of the block behind the bellhousing, One of them is 2", the other is 2 9/16". The other three are along the side just under the intake manifold.

(5) 2" Plugs
(1) 2 9/64" Plug
(2) 1" Plugs

Click to expand...

x2 on the freeze plugs. IIRC 1 of them in the back of the block is for coolant, the other for the camshaft/oil. You have to pull the engine or drop the transmission to replace it. A lot of work to replace like a $1 part.

Also is there a coolant temperature sensor on the top of the cylinder head back there? Not sure what years it was there, but check that also. It would be on the drivers side, top of the cylnder head next to the grounding strap. Much easier to fix if its that.

My guess would be the heads freeze plug has eroded through or rusted through if an original steel plug.

Freeze plug eh? You really have to pull the engine to get at it? If there's no other way to do it, maybe I'll just try some of that leak stopper crap and hope for the best...