Gt40 Head Leaking Coolant - Thermactor Hole?

[xkuntrycowboyx]

I need some help...
GT40 Head is leaking out of the hole pictured. It's at the back on the drivers side. It's leaking coolant as fast as I fill it with coolant. I've looked for cut-aways or diagrams for the GT40 heads and passages to find out whether or not this hole was at one time plugged and part of the water jacket? Or if it should be AIR only and my head is cracked internally? I've done a lot of research and found only comments about the larger freeze plug doing this.. please help me solve this problem. I've found threaded plugs to thread in. But would like to know why I'm suddenly leaking coolant when it never has before..??

Thanks for any help!
It's also been a long time since I've been around, please no bashing me...family, schooling, and career end up taking over..also, the mustang has been parked off and on for quite some time.

 

[xkuntrycowboyx]

I posted a thread in 5.0 Tech about this. I really need some help with it, but am now concerned a may have put it in a place it won't get much attention.

Please check it out in 5.0Tech if you know much about the GT40 Heads.

Thanks Guys!

 

[84Ttop]

@Noobz347 can you combine these threads?

 

[84Ttop]

Are you using Gt 40 or GT40p heads? The P heads as far as I remember don't have a thermactor port on the back of the head as they use an external EGR system?

 

[xkuntrycowboyx]

It may not be the therm actor hole. As stated, I'm unaware of what it is for. That is why I provided a picture with an arrow pointing to the hole in question.

(apparently I provided several pictures by accident - it did promt me that those other 3 did not upload. My apologies)

 

[84Ttop]

If the car has been this way for some time and not leaking from this whole and suddenly it is, I would imagine you have a problem. What temp is the coolant good down to? If the weather by you is anything like in Nj this winter we have seen several single digit days and I have two friends with cracked blocks already this winter. Just food for thought...

 

[7991LXnSHO]

Thermactor ports are a large (3/4"?) threaded hole with a 1/4" hole next to it. It is also nearer the top, outside corner. If it was an AIR hole leaking coolant, coolant would be going out the exhaust too.

 

[JD1964]

That would be an accessory mounting hole. If coolant is gushing out of it, my guess would be a cracked head.

 

[Noobz347]

@Noobz347 can you combine these threads?

done

 

[mikestang63]

pressurize the cooling system with the car off. See if you get water coming out of that hole- which is to mount the accesories. Those are 4 bar P heads that have an external EGR, so no thermactor ports. Good luck.

 

[xkuntrycowboyx]

Thank you guys, I didn't know if it was plugged from the factory, and somehow a plug had come out. My thoughts were to plug it and do a coolant system pressure test and see if I end up with coolant anywhere else... or in the oil.
It certainly could be cracked, but I didn't want to say that and lead anyone that direction. I wanted to actually find out what the holes were for first. Weather here in IN has been rough this winter, 0-Teens* weather consistently.. (-45*) windchill at times and it was parked outside. We should hit 30*'s end of this week and it's like a heat wave! When sweatshirts / no jacket is comfortable in 30* weather... you know it's been too cold!

 

[xkuntrycowboyx]

Update: I threaded a plug in that accessory hole today. Poured in more coolant... still pouring right back out.... A closer look showed it coming from the freeze plug, directly above the accessory hole. It was ever so slightly kicked out at the bottom. It was leaking down into the acc. hole and out of that, or so it appeared.
Now for changing the freeze plug without pulling the head!

Thanks for all of the input, ideas, information, and help.

 

[84Ttop]

If you pushed one plug out it would be in your best interest to look at the rest of them to see if they moved. Can't hurt to take a little time to do a careful inspection

 

[7991LXnSHO]

I know this is late, but here is a picture of the end of a head with a smog port.

 

[horse sence]

Be extra careful to get that plug in straight ,if it goes in crooked it will leak again or blow out .I would make a strap form a piece of steel about 1 1/2 inch wide and say 1/4 inch thick and use the two holes to thread bolts evenly in until it pushes the plug in place .The bolt pattern is the same in the front of the head as the back so you can get the measurements that way. I have done this before and it works great in a hard to get at spot.