Blew rear freeze plug on 408

[mopardude318]

I used red loctite on my freeze plugs

 

[rustycowll69]

you know no one asked if the soft plugs were the deep kind or the shallow kind. I would opt for the deep ones because they offer more gripping power and less likely to go in cocked.

 

[512Stroker]

I took my Swinger for a quick drive yesterday and got on it for the first time since building the car .
It hit 7k pretty quick then I could smell coolant . Luckily I was 1/4 mile from home . I popped a heater hose off on an earlier test drive but attributed that to the idiot that assembled the car not tightening the hose clamp ... LOL
Either the freeze plug wasnt seated tightly or I have a head gasket problem .

Clean up all the related surfaces and install a new brass plug with some No 2 Permatex let it set over night and then pressure test the system, you will find out quick if you have a head gasket problem.
Make sure you radiator cap is proper and functioning.
Any coolant in the oil? Or oil in the coolant?

 

[mbaird]

No coolant in the oil...
No coolant in the radiator either so its tuff to tell if its contaminated with oil ...lol

 

[mbaird]

you know no one asked if the soft plugs were the deep kind or the shallow kind. I would opt for the deep ones because they offer more gripping power and less likely to go in cocked.

I use deep brass ones.

 

[512Stroker]

No coolant in the oil...
No coolant in the radiator either so its tuff to tell if its contaminated with oil ...lol

Sometimes it will leave some crap on the inside of the cap or in the recovery tank.

 

[mbaird]

None that I can see.

 

[Dartswinger70]

I've never seen freeze plugs pop out. If one did I think an installation issue. OR a messed up sealing surface in the block etc. Usually in service, they rust out if steel. I am currently installing tall brass core plugs with Permatex 2. I would pressure test, get under it, pull the lower inspection cover and look up behind flywheel basically be sure it's a core plug. If you can't figure what it is, pull the engine do the head gasket and rear core plugs in one job. Really not that bad pulling the engine, it's psychological. Easier than laying over fenders and doing heads. In our mind we think pulling engine is alot, but it isnt if you have to get at the rear core plugs...

 

[512Stroker]

None that I can see.

I dont think you have a head gasket issue.
I would proceed with the plug replacement, refill the system and pressure test the cooling system.

 

[12many]

What about these Mr Gasket screw in style? They even make these anymore?? (And no, I’m not talking about those in a pinch rubber expanding butt plugs that pop out on you) Or how about the old strap trick? Easy on the big blocks, not sure if there’s enough flat material to drill into on a small block. I’ve read of riveting them somehow but not sure how easy that would be....

 

[MOPAROFFICIAL]

I took my Swinger for a quick drive yesterday and got on it for the first time since building the car .
It hit 7k pretty quick then I could smell coolant . Luckily I was 1/4 mile from home . I popped a heater hose off on an earlier test drive but attributed that to the idiot that assembled the car not tightening the hose clamp ... LOL
Either the freeze plug wasnt seated tightly or I have a head gasket problem .

You're not going to push a freeze plug out because of pressure building in the system unless the freeze plug was improperly installed and of story that's it.
First and foremost make sure it's in pressed in enough, especially if you're the type to use rvt..because if it's not set in right with enough inference..the rtv will actually help it pop out.

Been there, done that. My buddy. who is a pretty bright dude...helped pop plugs into my block and didnt set the rear enough...blew out on the first hard shift all over , clutch,pp.
Live and learn..and some things you only do yourself.

 

[brian6pac]

You're not going to push a freeze plug out because of pressure building in the system unless the freeze plug was improperly installed and of story that's it.
First and foremost make sure it's in pressed in enough, especially if you're the type to use rvt..because if it's not set in right with enough inference..the rtv will actually help it pop out.

Been there, done that. My buddy. who is a pretty bright dude...helped pop plugs into my block and didnt set the rear enough...blew out on the first hard shift all over , clutch,pp.
Live and learn..and some things you only do yourself.

The one I blew out on the 383 was in a 71 Chrysler Newport and it was in 1976 so it was factory installed and only 5 years old. I don't think it was installed incorrectly, It came out at WOT wound tight so it was a head gasket leak that pressurized the cooling system. It was my mom's car and my dad kicked my *** every day till I finished replacing both head gaskets.