Freeze Plug on Perkins

[JTHAW]

great replies all...I bought 2 rubber plugs today...1 as a spare back up...because its a bit tight to tap in a metal one, cable linkage in the way, I'll install these expandable ones...

[Boatyarddog]

Originally Posted by a64pilot

They are really casting plugs, allow the air to escape I believe when the block is cast, they are not there to prevent damage in a freeze, just got that name somehow.
The rubber one shouldn't be considered permanent, it may take ten years, but eventually that rubber will deteriorate, other than that, I know of no downside, I have used one in the past.

You've not seen what happens when you freeze an engine block without freeze plugs? It splits open.
It's why they are called "freeze" plugs. To allows for expansion of under protected coolant passages.


Sent from SV Cloud Duster

[Steven UK]

Just shooting my mouth off again, in a previous life as a Massey Ferguson mechanic we would change the plugs out by hitting one side with a hammer and refitting with socket and hammer with a hard setting goo. Anything none hard setting acts as a lubricant in structural joints and can cause the plugs to push out under pressure. In a later life as a Engineer for MF I learned that the real purpose of the holes is to support the 'core' of the casting ( the core creates the holes in the block for the cooling passages and is a resin impregnated sand that is vibrated out once the casting solidifies). But they also work well as safety valves if it does freeze. No real point to this post just adding / agreeing with what's going on... I like the rubber bung idea as an emergency fix I'll look out for some.

[JTHAW]

for future readers...the rubber expansion plug bought at napa was easy and excellent...works fine, with a spare onboard I would think it will last many hundreds of hours running, perhaps a 1000 hours
many thanks to A64 and Nicholson..easy fix
now to fix the glow plug fuel seep...

[rwidman]

Originally Posted by Boatyarddog

You've not seen what happens when you freeze an engine block without freeze plugs? It splits open.
It's why they are called "freeze" plugs. To allows for expansion of under protected coolant passages.


Sent from SV Cloud Duster

They are not intentionally placed there to take care of freezing, the holes are part of the casting process. The plugs are to fill the holes, nothing more.

Yes, they are sometimes called freeze plugs but that's not what they are.

[Arthur Garfield]

Yes-Nicholson58 and rwidman are %100 correct though these casting remnants do function as "freeze out plugs" also.I always replace with the rubber nut plugs when any go south.Often I'll replace other plugs at same time because if one goes the others are not far behind.Generally,I'll dry hole then light sanding/cleaning with 2-300 wet dry paper then skim coat steel and rubber plug with high temp silicone gasket sealer then tighten but not over tight-It's a feely thing here.

[rwidman]

I would view the rubber expanding plugs as "temporary" and replace them with steel as soon as it's convenient. Rubber will deteriorate with heat and time (think tires).