freeze plug failure

GregS · Post by **GregS** » Sun Mar 19, 2006 7:38 pm

Well, Murphy struck again.

Today I started the jeep and let it run for about 10 minutes then backed it out of the garage and parked it. All at once anti-freeze gushed from under the engine. The passenger side rear freeze plug gave way.

When I rebuilt the engine the machine shop replaced all the plugs and the engine probably only has about 1 hour run time on it.

Any ideas on what could have caused it to give out? The engine was good and warm but was not over heated. Think it was just improperly installed?

The plug was a cupped shaped and appears to have been sealed with hard setting Permatex. Any suggestions on what I should seal the next plug I install?

Greg

Post by **wesk** » Sun Mar 19, 2006 9:14 pm

I don't think anything is wrong with the sealer that was used.

I think the problem was with the setting of the plug. They require a very firm blow dead center with a punch to expand them properly. The sealant will protect against a rough edge seeping a little coolant but will not hold a plug in if it is not firmly set or seated.

GregS · Post by **GregS** » Sun Mar 19, 2006 10:27 pm

Thanks Wes, I think I will remove the passenger side fender to give me more room to set the plug.

Could you advise which of the 4 types of plugs should be used.

The one that was in the block looked like this but is steel.

Post by **Ryan_Miller** » Mon Mar 20, 2006 7:02 pm

Greg,

That sounds like an easy fix compared to what it could have been. I would have laid a gold brick after seeing antifreeze gushing out on the ground!

GregS · Post by **GregS** » Mon Mar 20, 2006 7:29 pm

Well this is what I have found and learned. I need the plugs like the brass one above. The #@$%@ machine shop had installed the plug in backwards and I didn't know any different from looking at it from the outside as every engine I have worked on had plugs like plug "B" pictured above. Instead of installing the plugs with the dished side out and seating it correctly to make it expand, they have it reversed.

So, I am going to pull the other plug and correct the mistake. By removing the air cleaner, ignitor, generator, oil fill tube and right fender I think I can get to the plugs without having to pull the motor.

I found my original invoice from the shop and am going there on Sat. to call them out on it. This is from a shop that has always done excellent work for me. They have done machine work and such on about 10 different engines for me; this really disappoints me.

Oh it couldn't have been as simple as forgetting to tighten a radiator hose clamp. On the bright side, I am glad it happened in the driveway and out on the road.

Post by **wesk** » Tue Mar 21, 2006 12:06 am

Greg,
Don't forget the back side of the block. If that little shiney bugger hiding behind the flywheel was also installed backwards it won't take long for the cam to bump it loose and there goes the oil pressure.

I would deliver the jeep to the shop and have them make their screw up right. Let them do the labor on the engine removal!

GregS · Post by **GregS** » Tue Mar 21, 2006 8:18 am

Thanks Wes,

Thankfully I took pictures of the engine, for my scrap book, when it returned from the machine shop. I reviewed them last night and the soft plug for the cam is in correctly.

Post by **Ryan_Miller** » Tue Mar 21, 2006 7:37 pm

Greg,

That is good you took photos!

Let us know how things turn out.