My 12a has the typical coolant passage o-ring failure on the intake. So I removed the intake (after much suffering and swearing) and installed 20mm freeze plugs and a new intake gasket. Bolted everything back together, refilled the coolant. and started the car. After several minutes, coolant started leaking from the intake.

Obviously I screwed something up when installing the freeze plugs. I haven't taken it back apart yet to see what exactly went wrong, but I'm assuming that the plugs pushed back out under pressure.

I used Dorman 20mm plugs and a 3/8 ratchet extension to drive them into place. Everything seemed to go pretty smoothly. I coated the edges with a thin layer of RTV then seated them so the lip of the freeze plug was just below flush with the block. Did I maybe not drive them in far enough? Is there a better tool to use than a ratchet extension... maybe a bushing driver? Are the Dorman plugs not a good fit?

I'd like the next time I do this to be the last time, so any advice is appreciated.

 

Is this engine stock as far as accessories goes? Air pump, rats nest, etc..

 

Air pump and rats nest have been removed.

 

You can either use the factory o-rings in addition to the plugs to ensure no leaks or use some JB weld over the plugs.

 

1. Remove old plug
2. Sand the circumference of the hole to get it nice and smooth.
3. Apply RTV silicone to the new plug.
4. Tap plug in flush with applicable socket and hammer.
5. Finally countersink the plug about 1/16" below cast with a smaller socket.

Edit: Do not run engine for 24 hours. Also if you didn't use a socket and you just used a 3/8" extension on its own, it's quite possible that the plug went egg-shaped just slightly.

When you initially tap the plug in be sure that you are using a socket the fits nicely on the EDGE of the plug. This way you lower the risk of damaging the plug.

 

Thanks for the suggestions. Finally had a chance today to take the intake back off. One of the plugs was clearly leaking and after pulling the plug out, it did look like it was slightly out of round. (Although I guess that could have happened when I took it out)I tapped in a new one with a socket instead of just the extension and will wait until tomorrow before attempting to fill with coolant and start the engine. Last time I didn't wait which may have added to my leaking issues.

 

Wanted to follow up with an update. I wasn't able to test my freeze plugs last weekend because some idiot accidentally snapped off one of the intake bolts (the idiot was me). Anyway... got that taken care of after a trip to the hardware store. Next owner of my car will wonder why one of the intake bolts has a 13mm head, but at least the threads were the same.

It looks like my leaks are sealed. Thanks for the help! Two notes for anyone who hasn't done this before. 1) I think the 20mm freeze plugs I bought at NAPA were a better fit than the ones made by Dorman. The Dorman plugs seemed to be just a tick bigger and were more difficult to get to seat flush. The NAPA ones seemed to slide right in. 2) I picked up a small 2 1/2 lb. mini sledge hammer at Harbor Freight that made things easier. There isn't much room in the engine bay to swing a hammer with a long handle. Using a hammer with a short handle made a big difference.