Ok, so I replaced my cylinder head about a month ago along with a new header, and freeze plugs. Keeping my eye out for leaks I noticed today the freeze plug towards the firewall was leaking along with the very front one, middle two are still holding up. I do have a closed system w/ new radiator WP.,Thermostat ect. Hoses no leaks there . What could have happen for these Two plugs to suddenly start leaking? Could it be because my reservoir tank was too full? It was full almost to the top, and I know it has to be about half way to 1/4 full in order for pressure to build , but my dumb *** kept driving it thinking it would go down. Anybody have a clue? Thanks in advance. Sorry this is a 1990 4.0 aw4 242tc.

 

More than likely they were installed incorrectly. Did you use brass or steel?

 

(Brass plugs) were used. Just wondering if I can get to the very back one - and the front one, with out pulling the head ? Drove it again in traffic checked several times, and now I don't see any leaks. I did drain some coolant out of the tank just a small bit. Making too much pressure maybe? when I had that bottle too full it had no room to expand.?

 

That's possible. If the plug on the back of the head leaks, the only way to get it is to pull the head and replace it.

 

And if you do replace the plugs, this stuff.

 

This will be the third time pulling the headin the past couple months. You can see where it was leaking. The pic with the numbers are in the middle.
This pic was taken after I drained some coolant and drove it for awhile. I wiped it with a paper towel now I don't see any leaks. Hmmmm

 

Old timer engine builder showed me that aviation sealer years ago after I messed up some soft plugs.

If your still running the closed pressure bottle setup, That bottle or cap will let loose before a properly sealed soft plug leaks. Gotta use the sealer or its a crap shoot that the block and soft plug are perfectly round and seated.

 

Next time for sure I'm doing it today actually. Drove it again last night and no leaks that I can see. my reservoir bottle keeps filling up and won't go down somethings getting blocked some where! I don't get it.... Not over heating one bit . Should I keep draining it until it stays half way?

 

Freeze/core plugs go in dry. But they must be straight, not cocked even a little.

 

Copy that thanks for the help.
There's something with my cooling system I think..
Aux fan switch quit on me today.

 

So since I'm replaced my head the closed system take keeps filling up to the max line.
When I shut it off and let it sit after along drive it just stays full to the max line? What's going on here??
Not over heating at all under 200* most of the time unless I'm stuck in traffic the once it reaches 210* fan kicks on, then back down to 195*

I drained some more antifreeze this morning before starting to about half way full.

What would cause the tank to fill up like that and not drain back after a long sit over night?
Thanks again

 

Take off the tank cap when engine cold. Warm up the engine at fast idle, heater on full.

You will observe coolant circulating in bottle when thermostat is open. Run it at fast idle for at least 10 more minutes after thermostat opens.

This should eliminate any air pockets, which it sounds like you still have. Cap the bottle.

After a couple of driving sessions hot/cold, check coolant level. It needs to be 1/2 to 3/4 way up the bottle, but not brim full.

 

Got it I'll try that see what happens..
Reservoir is staying half way full I'll look in the am. To see where the level is.

Front- freeze plug is still leaking a bit not too bad though.

 

It will either rust shut or blow out.

 

All it did is just fill up maybe check the thermostat once it cools down. Takes forever to get up to 210* for the fan kick on.