Coolant leak, rear of engine. Where is it coming from?

Let me give a little background here just incase any of the information is relevant:

I did a routine coolant change on my '92 N/A in november (i think) by pulling the lower radiator hose. put it back on and filled up the radiator. went for a drive and turns out that i now have a waterfall of coolant coming out from where the lower rad hose attaches to the rad. hurried home and deduced that it was an original lower hose and needed replacing. all said, 4 gallons of coolant and a new hose, and the leak seemed to go away. Although I don't drive it hardly at all. well, anyway just a couple of weeks ago before the holidays (about a month or so later) i moved it to a different spot in the apartment complex, all of 100 feet or so. I turn the truck off and now the drip is back! (but slower, like a drop per second) then magically 3 hours later, it stops??? i figured that the lower rad hose clamp is a bit lose so i tighten it and it hasn't leaked from there since. I have not moved the truck since then.
this afternoon, it is warmer here than it has been in a few days and now coolant is leaking but from a different spot!! the problem is, i can't tell where it is coming from. keep in mind that i have not started the truck.
The leak seems to be coming from the area around the back of the oil pan near what i think is the rear main seal, on the passenger side near a black cylinder that looks like the starter. hose is dry, water pump and thermostat are much farther forward on the engine so i don't think that is it. can anyone help?
I've attached some pictures so that hopefully someone who knows what they are looking at can tell me. you can see coolant on some of the bolts.

http://i133.photobucket.com/albums/q...o/IMG_0526.jpg
http://i133.photobucket.com/albums/q...o/IMG_0524.jpg
http://i133.photobucket.com/albums/q...o/IMG_0523.jpg

13 views and no one?
I am desperate!

I can take more pictures of the area if they are not clear.

OK here we go.
Hang on to yer Butt :)

Fresh antifreeze can go though where dirty old stuff can't

A fresh new hose will settle in after a warm up and the clamp will need a tweek or two.

Now up on top there are a few places in the rear of the engine that can leak.
There is a plate on each head right behind the intake manifold that covers the outlets that are not used (same ones that are used up front for the crossover.

These have a gasket and can leak down into the valley, then run out the weep hole and onto the ground.

On some models there is a temp switch that screws into one of the rear cover plates I spoke of and also some trucks have a temp switch in the rear outside of the RH head..

Other than these places it should not be leaking.

The little plates on top use a gasket but you can use just Hi temp RTV in a pinch.
I prefer to use the gaskets with RTV on them too.

Its not impossible to have a head gasket start seeping out the back either.

If this is the case then things are far more serious.

If there is not any leaking into the engine or compression leaks, a can of Bars Leaks might do the trick.

Be sure that you dont have a soft plug on the side above the starter leaking.

These sort of leaks can wander down and drip off farther back.

A bad soft plug can so just what you complained about.

The plug on the rear above the starter can be replaced with a rubber expander type.

What happens is the plugs rot out from the inside at the lower edge and with the fresh antifreeze can start leaking.

If it is a plug, dont be tempted to use a stop leak, remove the plug and replace it.

The rubber expander ones will do the trick for a long time.

The best way to do it is to drain the coolant back out, then get access to the plug.
Poke a punch through the plug and catch the coolant.

Now using a large punch and a hammer, drive on the top inner side of the plug (in the cup itself) to drive it into the block or at least turn it on edge.

Pry it out of the block.

Now clean and dry the hole, making sure to remove all the rust and crud.

Dry the hole well and then insert the rubber expander plug, then tighten the nut to expand it.
\
Replace whatever you tore off and refill with the coolant.

Good to go.

Now, a word to the wise, if you find a bad soft plug, then likely the rest of them are rotted out too, or nearly so.

If you can get enough room to work, installing new metal plugs is a good idea.

Same prep, just smear the plugs and hole with permatex #2 and drive the plugs in till the lip is flush with the blocks lip.

Good luck and let us know what you find.

Missy

Missy,

Thank you for the response!

I have a couple questions/comments:

Can you give me a little bit of a description of these "plates" you speak of so that I can identify them a bit easier?

I am assuming when you refer to "soft plugs" you are using that term interchangeably with the term "freeze plugs" that serve the same function?

Quote:

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Originally Posted by Robyn

If it is a plug, dont be tempted to use a stop leak

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NEVER lol

Alex

OK

The "Plates"

Look at the front of the heads where the water crossover bolts on.
The crossover bolts over two water ports, one in each head.
There are two of the same ports on the back of the heads right behind the intake manifold.

The "Plates" are fastened onto the heads with two bolts each and cover the water ports.

Yessssssss

"Freeze Plug" "Soft plug" "Core Plug" all the same animal.

Goes in the 6 holes in the side of the block (3 on each side)

Missy

Sounds good.
I'll have to take a look tomorrow. It is really hard to see behind the intake manifold but crawling into the engine bay and trying to look back there, i could see a little bit of what looks like moisture in (what i think) is the valley area. Although this truck has so much crud and leaking oil build up, so who knows? If i would have known i was going to inherit all of these proximate problems that I can't just leave until spring I would have taken a closer look at the truck before handing over the cash (and my sanity).
Live and learn i guess :(

Just one more thing if it isn't too much trouble,

Can you tell me how to get to the passenger side soft plugs? It's not in either of the 2 manuals I have.