freeze plugs in 304

3 freeze plugs in my 1974 CJ5 have pushed out would it be better to put brass ones back in or just buy the rubber ones that you can tightrn up?

 

****Ignorance alert****

Can someone explain to me what freeze plugs are?

 

These are also known as "soft plugs" If the water freezes in your engine, it expands and will break the block. Freeze plugs give a place for that frozen water to expand to...a door for the expansion to get out..


AND....they both work well. The rubber ones will work...and you will be MUCH easier to install with the engine in the Jeep. Try and get the hole as clean as you can and as dry as you can (same with the plug) and install it. Don't use any sealant of your going with the rubber type plug.

 

I never knew expandable rubber plugs could be used this way. Anyone have a link to where one could find such things? I have a leaky plug in my 304.

Thanks,
Chilly

 

Since I don't have the TSM in front of me, could someone provide a picture illustrating where these are located?

 

The freeze plugs were designed to drain the casting sand from the block when it is cast. They do work well to pop out when the block freezes and not crack the block. I replaced mine with the brass ones but the rubber ones work just as good. Any parts store should have them. just remove the old one & give them the size you need. The rubber ones are easyer to install if the eng. is still in the Jeep.

 

Like this.

http://cgi.ebay.com/#02601.-1/4-"-r...ItemQQimsxZ20081129?IMSfp=TL081129105002r2993

 

The rubber ones are ok, but once in a while I find them along the road. Obviously not a permanent fix.
I have seen a mechanic replace the metal plugs while the engine is in the chassis. There is a special tool for this job.

 

I have this tool, and use it. The rubber plugs ARE referred to as a temp fix...I would have to disagree with that though... the catch it getting the right size and installing it correctly. I have seen many people think that they are helping it seal by putting a little sealant around it...This acts as a lube and will not let it grip the walls like it should. These things (when done right) will not fall out, they are in there very tight. Over time, the rubber will harden or rot....But I have seen these goofy things hang in there for decades (literally).
Now, I will say that I prefer brass in my engines...but I can tell you that a rubber plug will last you quite a while.

 

This is a complete myth!!!
Freeze plugs are the cleans outs and supports for the sand core that cast the water jackets in the block, that is all they are for, nothing more. If your block freezes they will not pop out and will bust the block!!!!!
I cannot count how many times I have heard this description of freeze plugs before and it is an old wives tale.

 

Well...I will give you the FACT that soft plug hole were made to pour the sand out of the engine block...but to refer to a freeze plug, soft plug, expansion plug, coming out when a block freezes as a "complete myth" is pushing it a bit far. It is true that they do not always work. Here is the thing though...and we all know this...When water expands...it will come out of an opening (the plugs). Whether or not it will do anything to help keep the block from cracking......big maybe on that one. I can tell you this though. They WILL pop out a large percent of the time. Even had it happen to me once when I was a kid (also see not ready for cold weather). I worked for CAT for a while as a field mechanic (miserable job)...We would find freeze plugs pushed out from a freeze and the owner not having enough anti-freeze. Would the block always be broken? No...but there were times that it was. Did the plugs save the block by allowing the water to expand a little more? I don't know, but it absolutly pushed out the plugs on many occasions.
If I were to take a guess...I would say it might be a "timing thing"...Like this. If you put a jar of water in the freezer with no lid on it...when the water starts to expand, it will come out the top before the jar breaks. If you were to pull the jar out before it cracked, but had the water coming out the top...In this case, a soft plug may have worked. We all know that left in the freezer...even without a top...the jar will break pretty soon. Same with an engine.
Now...I suppose that there are a lot of cases where the plugs stayed in place and the block cracked....But in my own personal experience...at least one of the plugs was pushed out.

 

I didn't mean that it doesn't happen but they are in no way designed for that fact. They are simply there to support the sand core and to allow clean out. If they happen to save a few blocks along the way, great, but they are not there for that purpose and never were. I have seen lots of blocks over the years busted and guys always say the freeze plugs didn't work, I have to remind them yea they did work, for exactly what they were intended, clean out.
Years ago they were even tapped and had screw in plugs, that was eliminated due to cost. I just don't want guys depending on these things cause they rarely save the block.

 

Wouldn't it be prudent to just use the appropriate amount of antifreeze? Is there some reason that using water as a coolant long term is a viable option? Once again the ignorance disclaimer is in effect. Thanks for the education guys.

 

Yes....
Some guys stuff will freeze just do to lack of maintenance. Like, they will add water and not antifreeze so much that it will dilute it...
But....water does cool better than anti-freeze. Like straight water, or straight water with "water wetter". But most of the time this is not done in daily driver type of cars. So...yes...just use the right amount of antifreeze for your climate.

 

Thanks for the help I went ahead and installed 3 rubber plugs. It turns out that the water had not froze in the block all 3 of the plugs had small corrision holes in them and the po had filled the block with stop leak and i had got it stired up enough this summer that when I drained it and went to refill it the holes were open.