Originally Posted by MikeLSXSHAMU

This engine is getting pulled soon anyway, is it worth taking out the stock freeze plugs and welding in Aluminum plugs?

Originally Posted by Blown06

There is 100% no reason no to do it. Matter of fact, I'll paypal bux to a person who can tell me a legitimate reason not to do it while the motor is out of the truck and torn down for a build.

OP, if you can't find anyone in your neck of the woods who can do it, let me know.

Originally Posted by 1FastBrick

In a race only setup I see your point.

In a daily driver, I disagree. There designed to pop out if things freeze in cold weather. Since they no longer have them on the block on these engines, I would not weld up the head plugs. When it freezes in the engine, it has to go somewhere. If it has no place to go, it will likely crack something.


Same thing can occur if you over overheat and over pressurise the cooling system. Especially if you don't maintain the cooling system and there is corrosion in there.

Your better of cleaning the area, applying glue or sealant and popping another plug in there.

I personally use sleeve a retaining compound on any plug that has to be replaced.

Originally Posted by vettelovralexand

I have been running these PRC stage 1 heads for about 1000 miles now and havent seen any issues until today. I rolled into the throttle and at 4k rpm i got a message saying the engine was hot and it was killing the A/C. Sure enough it was running pretty warm and the hand was moving fast. I coasted down into a fire station and as i pulled in it was still getting warmer and so I killed it. Pop the hood...coolant everywhere on the passenger side. No hoses gone or popped so it took a second of looking over the water loop before i noticed the hole on the front of the head where the freeze plug goes. Had my wife get me, we bought a few gallons of coolant and a .74 cent dorman plug. Punched it in at the fire station and filled it up with coolant again. Let it get up to temp and made sure it was full before i capped it and drove home.

Anyone else ever have this happen?

Originally Posted by 1FastBrick

In a daily driver, I disagree. There designed to pop out if things freeze in cold weather.

Originally Posted by MikeGyver

I thought that "freeze plug" is a misnomer, and they're actually core plugs, just plugs for the holes that are needed for cleaning out casting sand.

On a side note that might apply, I learned that when a water pipe bursts from freezing, it's not from the direct force of the ice expansion. The damage is actually from water pressure coming from ice expanding on either side of the water.

So how could a "freeze plug" be strategically located to prevent freeze damage if what I said above is true?

Originally Posted by strutaeng

Yup, that's what I understand as well. But they often do pop out if engine water freezes and I'm guessing that why folks call them freeze plugs. Back in 1993 we moved from SoCal to Texas in the summer. Our 1972 C20 with a Buick 401 we drove here had 100% water in the coolant system. The first freeze in November the engine froze over. Luckily, one of the core plugs popped out.

Aren't these plugs on LS threaded on? What happens on those if they freeze? The block blows? Don't the heads have some press fit plugs?

Originally Posted by MikeGyver

I thought that "freeze plug" is a misnomer, and they're actually core plugs, just plugs for the holes that are needed for cleaning out casting sand.

On a side note that might apply, I learned that when a water pipe bursts from freezing, it's not from the direct force of the ice expansion. The damage is actually from water pressure coming from ice expanding on either side of the water.

So how could a "freeze plug" be strategically located to prevent freeze damage if what I said above is true?