Topic: Freeze Plugs???
in Forum: C3 Engines
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Former Member
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Chicago, IL - USA
Joined: 11/30/2007
Posts: 37
Vette(s): 1976 L48 T-top, Automatic, ps,pb,a/c, Everything stock. Good car in great shape.
Hi again all...I'm sorry that I have been offline for a while. I got married, bought a house and my business is expanding to California, so I've been real busy.
Has anyone ever heard of "Freeze Plugs" and if so, do all vettes have them and how can I tell if mine has/had them? Over the winter, my car was in a new garage that was not heated and was probably exposed to below freezing temperatures for the first time in a long time. Needless to say, it dropped a lot of oil/something and a guy told me that I probably had freeze plugs that cracked/broke and that's why all the oil/liquid on the floor...??? Can anyone confirm if this is a possibility???
Thanks!
Monte
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The freeze plugs on on the sides of the engine block, hopefully someone might be able to post or give exact locations they look like a circle indent about 1.5 inches around. I beleive there is 4 on the sides and 2 in the rear, they are soft metal and designed to push out if the water in the block freeezes. but if you had sufficent antifreeze you should have been ok rraider1 2009-04-10 09:19:48
Former Member
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Chicago, IL - USA
Joined: 11/30/2007
Posts: 37
Vette(s): 1976 L48 T-top, Automatic, ps,pb,a/c, Everything stock. Good car in great shape.
I'm pretty sure I had sufficent antifreeze...
What does the fluid look like? the possibilites would be Antifreeze green or yellow, Transmission fluid red, oil black and power sterring fluid could be red or clear looks like oil but thinner
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Actually the term freeze plug is a misnomer. They are casting plugs, and have nothing to do with protecting the engine from freezing. They are located on the side of the block just below where the heads contact the block. There is a total of four. Two per side. The front two are behind the motor mounting brackets. They are also called expansion plugs.
corvette440hp
To replace a freeze plug: First off, this is a dirty greasy job if done with the engine in the vehicle. But basically all you need to do is jack up the car,(use jack stands),high enough so you can move around under it. You may have to remove exhaust components depending on which freeze plug you have to replace. These things are made of soft aluminum or brass. Just take a sharp drift and hammer it into the middle of the plug then pry it out. Make sure you have drained the coolant first! Clean the hole with a piece of sand paper to remove any corrosion and then grease up a new one and tap it in till it seats.It is basically an easy but greasy, slimy and potentially knuckle-busting job. helps. You will have to support the engine when working on the front plugs.
corvette440hp 2009-04-10 09:43:01
corvette440hp
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Mounds View, MN - USA
Joined: 5/24/2007
Posts: 1031
Vette(s): 70 LT1 coupe, 69 350 HP coupe, 69 390HP 427 coupe, 71 LS5 convert, 85 coupe, 93 coupe
Besides the four on the sides, there are two inside the bellhousing, and two on the front of the block. If you are leaking coolant, also check for any cracks in the block or heads.
But the first thing is to determine what is leaking. Soak up a bit of it on a clean white paper towel, and take to a knowledgeable mechanic for a definitive answer. There is no point in worrying too soon. Automatic transmissions often leak a bit when they sit for a few months, and then stop when you drive them. So it might not be a problem at all.
Good Luck
Larry
But the first thing is to determine what is leaking. Soak up a bit of it on a clean white paper towel, and take to a knowledgeable mechanic for a definitive answer. There is no point in worrying too soon. Automatic transmissions often leak a bit when they sit for a few months, and then stop when you drive them. So it might not be a problem at all.
Good Luck
Larry
Larry is 100% correct about the other four plugs. The two up front near the corners just under the heads. The two rear are in the upper area where the flexplate/flywheel is. Larry, thanks for pointing out the other four plugs
corvette440hp 2009-04-10 10:27:42
corvette440hp
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Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
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If the car has plenty of anti-freeze, I doubt the freeze plugs are a problem. I would be more inclined to suspect a coolant hose leak, or something else. 
Joel Adams
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Hey Monte! I wouldn't worry about the freeze plugs.
Every year I have winter storage guys pull their cars out of my barn surprised to see various stains on the floor. Oil, AT fluid, and the occasional anti freeze puddle. Even the nicest cars. Usually just minor oil seepage, and the anti freeze puddles we usually trace back to a heater hose clamp.
There is one point on the motor that leaks anti freeze quite often, tho, and that's the intake manifold at the front or rear water passage. Usually very minor leak. I had it happen on my 78SA and I sometimes see a drip on my white79 after a ride after it cools down. Fixed the 78, one of these days I'll do the 79.
Had a puddle under the black79 this winter. Vacuum heater hose shutoff valve was leaking. New heater hoses and valve solved it. Found an exact NOS valve, too! Can't seem to pinpoint the leak in the old valve, even under 100 lbs air pressure, but that's where the fluid was coming from.
in Forum: C3 Engines
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