The Stovebolt Site Forums The Shop Area Engine Shop do freeze plugs work

will freeze plugs keep a 350 block from freezing? Asking for my son, who had some antifreeze in but not enough to protect for a 10 degree morning. He said it appeared not to be frozen solid, but slushy and the front freeze plugs was draining a small dribble. Also some fluid around thermostat connection. He has not atempted to start engine.

Any recommendations?

They are not freeze plugs...but core plugs used to get rid of sand from casting....hope the block is ok.....

the soft plug is rotten, replace it - new gasket on stat housing, proper coolant mix in, and yer good to go, 10 isn't cold enought to crack a block if there's any antifreeze in it at all

Bill

Son said there was some antifreeze in it, enough to be slushy. He didn't start it. One of my hot rod buddies advised to have it towed to a garage and let it warm up and have them inspect it tomorrow.
Son is 20 and learning the hard way. I asked him back in the fall if he checked his antifreeze? He said yep in a disgusted way. I asked him today what changed since then? He said "nothing I guess". Probably won't be the last time he doesn't listen, but, I hope he starts to learn that I'm really trying to help.

Hopefully there is no real damage.

1958GMCnut,

I have always been under the impression those were 'freeze' plugs, or soft plugs, and that while they may allow the core to be shaken out of the casting, a primary function was to protect the block when things froze and no antifreeze was in the system.

Isn't this right?

Stuart

I know a few people who incorrectly assumed the plug would pop out and not crack the block.

I wouldn't worry about the block freezing at 10 degrees. However the radiator might fare so well.
I had a 60 F%$& 1/2 ton six that set out all day in 5/10 degree weather with clear water in it. I cranked it up and drove toward the house. After a few miles I noticed the heat gauge had run up to red line hot. I couldn't understand how it got hot when it was 5 degrees outside. When I got home I discovered the radiator had frozen up so water wasn't flowing to cool the engine.
Ain't it fun to ramble?

"Freeze" plugs are there to pop out and tell you've got a cracked block. Being able to take them out to clean the water jacket is the only good purpose they serve.

ttdodd has got that right - I'll add that the plugs might more properly also called block casting plugs.

Tim

Excellent article,Tim. Thanx.

The plugs make a good location to put in a block heater. Other than that, they will fall out after you have block damage to let you know that you have block damage.

I bought a 78 Monte with a 305 that froze. Each side of the block had a 12 inch crack across it but the core plugs stayed. There's no such thing as freeze/frost plugs,
Scott

A friend of mine bought a small block that had been 'rebuilt' by the PO.
Everything looked fine until he cranked it up. All was not well.
On investigation he removed the intake to find both cylinder walls cracked the full length of the block!
All the freeze plugs were new and still in situ.

Another reason to live in Coastal Louisiana. Having said that, if someone would invent a water proof truck and engine, the Hurricane season would not be a problem

Does anyone make a Hurricane Plug for the engine, or am I jut confusing that with a Hurricane Drink, which has PLENTY of antifreeze in it.

http://www.patobriens.com/patobriens2/havefun/hrricane.asp

http://www.patobriens.com/hurricane.html

I lived in Northern Minnesota for a period of time and alot of folks have "block heaters" to aid in starting engines in extreme cold. 20 to 30+ below zero. Up there it's the oil that decreases in viscosity and becoming like molasses in below zero temps making engines harder to start and wearing out batteries. Don't know if a block heater would prevent an engine block from freezing up and cracking or not. I wouldn't want to risk that chance. Instead I'd make sure that my anti-freeze is rated for the climate I live in. In fact I'd go ultra-conservative and buy the lowest rated anti-freeze just to make sure and if I am living in the frozen tundra, I'd probably install a block heater for extra peace of mind. And remember, there is raw air temperature and then there is that thing called wind chill!!

Another simple thing one can do to keep that engine block warm is to place a large wattage light bulb under the engine. Preferable in a garage and out of the wind. It can at least throw off some heat but you still need properly rated anti-freeze.

Anti Freeze is a must summer and winter for me.

My favorite type of heater in South Dakota is a lower radiator hose coolant heater ($15-25). It's easy to install and heats the coolant. Block heaters work well, but I would choose the radiator hose heater because of ease of install and it works just as well.

My tractor will start OK with a coolant heater, but in sub zero weather I have to also use a magnetic oil pan heater ($25-50) to get the oil warmed up so my oil filters won't bulge and leak. For the tractor I use both heaters for 1-2 hours before I start it.

My old ford tractor won't start unless I put a hubcap full of hot charcoals under the oil pan. But when the temp gets below 40 forget it.

Freeze plugs are a name thought up by someone many years ago. They are not meant to prevent freeze damage but rather are the holes in the casting that is necessary to remove the casting mold sand after the iron sets up. For many years they were called "soft plugs" until someone decided freeze plugs sounded more glamorous.

I think the term freeze plugs may have come about when someone had an engine to freeze up and when the water froze it expanded and pushed out a "weak" plug.
I personally have seen this happen on my granddads old truck. I suppose the plug was so weak and rusted that when the water froze it pushed it out.
Back in the "old days" I have seen my grandparents actually lay a heavy quilt over the front of the grilles to help keep out the cold. He said he couldn't afford but one quart of antifreeze and the quilt helped. I can still see him doing that in the mid 50"s.

Well, you learn something everyday on the Stovebolt. I will now refer to those critters as 'core shakeout hole plugs'...although, soft plug does seem easier. Merry Christmas to all.

Stuart