Mud dauber or I messed up.

[MrPM]

Hello everybody,

I had coolant stains on the right side of the engine and assumed a blown head gasket.
This did not turn out to be the case as I found a pinhole in one of the freeze plugs. The picture shows it already bigger than it was as I poked through it while cleaning it with a pick.
Seems like this was already like this for a while as a ‘rusty bulge’ developped on the head.
The gasket and everything else looks “brand new”. My suspicion is that during an overhaul (indicated on engine) everything was serviced except that one freeze plugs.

It is while taking care of this that I noticed three holes in the head that were plugged with (what I assumec) mud dauber dirt….
Without second thought I cleared the holes. However when I moved to the second head, the same holes are plugged!!
I do not see anything about these holes in the manual I have. There are no matching holes in the headgasket either. My question is now:”Did i mess up the head? Can/should I replug these holes? How? Do I leave them open and have the gasket work it’s magic?
Thanks in advance for the help.

 

[tommys2patrick]

from my experience, I would replace all freeze plugs everwhere on the engine and the intake manifold. regarding the mud dauber nest, nope, not unless the engine had been disassembled for years outside. check the block for matching holes same as the holes plugged on the head. it is possible the wrong head gasket was installed. gaskets do not seal holes, they only seal between matching solid metal areas of the head and block. the water channels in the block and heads need to be thoroughly flushed and clean before reassembly . the freeze plug people sometimes miss is on the rear of the block and can't be easily seen. you access this area by removing the toe kick panel above the transmission. Lastly, something does not seem right with this situation. again from my experience, pinholes don't form in freeze plugs unless the coolant is not moving well behind them or in the case of the coolant intake manifold, is pooling over long periods on top of them. also was coolant in the block or was it just tap water. a lot of folks in the warmer climates run tap water for a coolant. not a good idea. coolant has superior heat transfer properties, is a lubricant and will keep interior corrosion to a minimum. it may be labeled as anti freeze in the store but thats only one of its jobs. yes you can use tap water. works fine in an emergency. so does pee if you have enough. also the mud daubers plug is just corrosion build up from poor circulation. the radiator, thermostat and water pump should probably be looked at as well. Please don't take my comments in the wrong way. I would rather you had an operating vehicle and wish you well in your work.

 

[MrPM]

Thanks for the feedback Tommys2patrick.

The truck had good coolant in it.
I already got the parts numbers found on this site for all the freeze plug. I’ll definitly check pump and passages!
It makes sense that crud would end up in a ‘dead end’ coolant passage.
I opened the new gasket and it is exactly the same as the one I took out. On it there are 10 holes on the exhaust side. On the block there are 10 holes (stud = hole) on the exhaust side. On the head there are 13 holes on the exhaust side. (Of which 3 plugged solid). Could it be that the heads don’t match the block?
The engine is a LDT-465-1D, 1980 continental.

It was put together like this at one point, but I am hesitant to put it back together like that. As you said, a gasket should not ‘close off a hole’.

Anybody on the forum by any chance has a cilinder head ‘exposed’ to count the holes on the exhaust side?

 

[tommys2patrick]

very interesting. looks like no matching hole on the block side.