Question about cylinder head

[Hartsell61]

I have a question. I ordered new cylinder heads for myv2003 4.0l explorer. My question is the driver side that came has a triangular bolt pattern with a hole in the center of it just behind the intake holes While the stock one had the the bolt pattern but there was no hole in the cast anyone know anything anything about this?

 

[EBfan]

There is a hole in the cast your original is filled with a core plug - I believe you guys call them freeze plugs or possibly expansion plugs ?? They were put in place as the sand casting of the head requires the holes that are created for the coolant to end in another hole to make a nice smooth casting (i believe) these are then later filled with the brass plugs to stop the coolant (and water) just leaking out of the engine.. The freeze plug label is a bit of a misnomer as they supposedly would tackle the frozen water inside head (and block) scenario of it causing the head and/or block to crack when frozen heated etc - Unfortunately i don't think it happens that way ..Someone will be along with a better explanation for you i'm sure but they are a simple brass plug that taps gently into place - They are pretty cheap so new ones are a good idea ..

Edit to add there are two casts one of course is for the thermostat on the front the other is on the rear and has the core (freeze) plug in it as can be seen in this thread http://www.explorerforum.com/forums/showthread.php?t=296492

 

[Hartsell61]

I get what you are saying. I looked at the head gasket and the gasket for that head does not have an opening on that jacket between the head and block where the one on the other where the thermostat sits does. What I am wondering now is if a plug in that hole is even necessary? Does anyone know where I could get that plug and the specs of it in the case I do need it?

 

[EBfan]

Yes the plug is needed as i said it's a plug to stop all of the coolant spilling out of your engine (a left over from the sand casting to enable a smooth casting of the coolant ducts inside the heads and engine block - There should be more under the exhaust manifold on the engine block i believe - They are incredibly cheap so there's really no reason not to do it and because if you don't all the coolant will flood out more reason to do it - I'll respond in a minute and see if i can find the correct one for your vehicle

 

[EBfan]

Not sure if you have the sport trac or not but either way i'm pretty sure they are the same core plugs - You may have to measure your original just to make sure you get the correct one in there and it does have to be accurate so calipers is probably the best way to go in the new head hole https://www.rockauto.com/catalog/moreinfo.php?pk=1261362&cc=1385355&jnid=574&jpid=3 - I hope it's ok to post that link in here