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I would remove the plug, clean the area in and around the freeze plug hole (use a solvent, wire brush, scotch pad) then if you still see a crack take some photos and post them. If it looks good then go rent a freeze plug install tool (any auto parts store) like the one in the video and install a new plug. Go slow and keep the plug square to the block as you install it. The sealer you used will work (Better than what I use). I just use black 3M weather strip adhesive.
I was going to suggest the 3M weather-strip adhesive but the yellow colored stuff (don't think there is a difference between the yellow or black stuff) and to weld the crack is going to be more trouble than its worth. As a last resort try some J-B weld on the inside and outside of the hole and contour file at the hole opening. It's either that or replace the block. This is a real MFer.
Thought I might try working from the top of the engine.
Set up a mirror to see the leaker.
Add coolant through the Temp Sensor hole.
Didn't leak at first, dammit. But after a half hour, got a bubble starting to show.
The case integrity where I thought the crack might be was cleaned off and looks alright.
And the inside edge where I thought the crack went across looks good too.
But the main point here, I feel anyway, is the plug is just too far driven in. It's a tough perspective we get looking up AND to the side when driving this plug in on our back. Hard to get started into it's hole and everything.
Going to try working from the top of the engine now.
I guess your best bet is to buy another freeze plug and start over. Basically you are going to fix it permanently, or just to get by for the summer. One or the other.
If after another plug is installed and you still get some weepage (that's a seep & a weep together) slather the rim of that plug with a good RTV that can handle heat, glycol, and 20 lb of pressure and call it good until next winter.
Last edited by HeadsU.P.; Apr 22, 2019 at 04:30 PM.
Rather than RTV for this use, I prefer Permatex #2 non-hardening in a tube ... tried & true before and since RTV ... same for water pump & water neck gaskets.
I agree with the Permatex #2; this will guarantee a good seal (as long as the bore and the plug are not damaged during installation). But it is also important to know that the primary sealing location on that freeze plug is the contact line, around the plug diameter, where it begins to roll over to the face of the plug. Yes, it can seal on the O.D. if sealer is applied to the bore (and it isn't wiped off by the plug during installation); but that line of contact is where the primary point of sealing is located. If the plug is driven in too far, that contact line will likely be inside the block so that it can't do its job. Your task is to drive the plug only so that the outer edge is flush with the surface of the block.
Last edited by 7T1vette; Apr 22, 2019 at 09:39 PM.
A quick glance at Permatex web site shows that Permatex Black is more for oily contact of sealing such as valve covers, timing covers, etc. You are trying to seal Glycol. No oil there at a freeze plug.
Permatex also makes a Water-pump & Thermostat Housing RTV gasket maker, part # 22071. The key word here is sealing coolant parts that contain glycol.
Last edited by HeadsU.P.; Apr 23, 2019 at 08:20 AM.
Permatex #2 is not a black RTV product; it is a sticky reddish brown goo that has been used for car engine gaskets to airplane components for many years.
Cleaned up the hole with acetone, got out the borescope, and here's what it saw.
Not cracked, but gouged bad from the drift when the plug was knocked out the first time. Pretty damn sure that's the leaker cause.
Anyone think I should de-bur it, maybe with a Dremmel sanding drum, before plug installation?
Where is your sealant? Shouldn't you have something smeared around the edge?
Oh yeah. Just positioning it up there to show what a pain it is to drive it in.
Going with this product.
The motor is raised about as far as it can, as currently configured, with the Radiator Fan Blades just starting to touch it's Shroud Extension and the Distributor is like a half inch away from the Windshield Wiper Motor housing. Plus there's probably enough stress on that left Exhaust Header plumbing that I want to put on it.
Potentially devastating.
