Freeze plug?????

[OUbesto]

My c10 has been leaking a fair amount of coolant but not while it is running or within a reasonable amount of time after engine is turned off. However, its not until the next morning that about a 1/2 cup of coolant is laying on the garage floor. So I jacked up the front end and the only place I could see a possible coolant leak was coming from the freeze plug(?) located (circled in red in pic) just above the starter on the passenger side of the engine block. I recently purchased truck so I don't have any history but it appears to be a fairly new plug. I hooked up a socket and tightened it a number of cranks and it seemed to stop leaking from its perimeter. I wasn't sure how tight to crank it. I had to leave the truck last night which is about 50 miles where I store it so I'm not sure if leak has stopped. Any thoughts if I'm on the right track here? Any suggestions? Is this plug the correct solution, or, is there a better or more effective option to consider?

[swamp rat]

That is not a freeze plug but it should be! i think that's an expansion plug, meaning a rubber donut surrounded by a couple washers and a bolt nut thru the center to make the rubber expand, I'd get it out asap and drive in a real freeze plug with proper sealant before it blows out under pressure, your asking for trouble by running it.

[OUbesto]

Thanks Swamp Rat. I have never seen a plug like this so I was thinking it was some new invention. Will definetly replace ASAP. I have never replaced freeze plug before. Any advice? Buy replacement freeze plug from auto parts store, Chev dealer, other? What kind of sealant best to use?

[Shady Rascal]

1 5/8" freeze plug from any auto parts store. They will all be selling Dorman brand plugs. Put a small smear of Permatex#2 around the edges and bang it in with a socket.

[OUbesto]

Thanks Shady R

[46stude]

Why would they use that? Freeze plugs are dirt cheap. I hope it's not hiding an unexpected problem....

[Shady Rascal]

A lot of people can't manage to hammer in a freeze plug straight if you held a gun to their head so they go the ghetto route, or they're just not aware of how easy it is to do correctly. I've seen the expanding plug deal done a lot of times over the years for lack of a 1.50 freeze plug and ten seconds with a hammer.

And, I've never seen one not leak in short order either. Half the time they wind up popping out under pressure.

[Gmc.guy]

Up here it's an extra block heater plug. Haha. Seen 4 on a small block once

[cypressbog]

Don't buy the cheap ones. Get a brass one.

[mike16]

Originally Posted by swamp rat

That is not a freeze plug but it should be! i think that's an expansion plug, meaning a rubber donut surrounded by a couple washers and a bolt nut thru the center to make the rubber expand, I'd get it out asap and drive in a real freeze plug with proper sealant before it blows out under pressure, your asking for trouble by running it.

x2. its a common fix but risky. They are easy enough to remove and replace.

if worse comes to worse. replace it with a block heater

[mike16]

Originally Posted by 46stude

Why would they use that? Freeze plugs are dirt cheap. I hope it's not hiding an unexpected problem....

its not a question of the price of the freez plugs, it about the ability to istall a freeze plug. Lucky its not the one behind the motor mount or ....behind the flywheel.

the bad news is that if one is going bad.....all the rest are too. including ones behind the motormount and the flywheel.

might as well do them all and a clutch job too.

[El Dorado Jim]

Originally Posted by cypressbog

Don't buy the cheap ones. Get a brass one.

x2 brass wont rust out, the rubber plug is there for a temporary repair only, you are lucky it is one that is easy to get to and not behind the motor mount

[cdowns]

i's spend the extra time to completely check all the other freeze plugs to make sure they are all ok and not on the vergr of failure in the near future

[davepl]

A previous owner probably had one fail (I have that happen once on a 350 when I was 12 hours from home) and the expansion style is much easier to install on the roadside or in a parking lot, that sort of thing.

Particularly if you don't have the space to get a big socket and hammer in there where the engine happens to be sitting.

[GRX]

Be careful over tightening those. Have seen them pop out that way. I would almost bet the PO just drove the failed plug into the block instead of removing it. And I would not sweat getting a brass one. Steel will be fine for decades in a properly maintained cooling system running modern anti-freeze.

[OUbesto]

Thx, all really good comments. Will try to attack the replacement tomorrow.