Let's talk about freezeplugs
 

Okay guys, my memory is fading and I need a refresher from some of you. I've got three questions on this subject.

1) What size of freeze plugs are you supposed to buy to block the coolant passages in the intake manifold? I thought that 20mm was the correct size.

2) People always say that they are using quarters to block the passages instead of freeze plugs. A quarter measures 24mm. How can a quarter and a 20mm freeze plug both work when they are not even close in size? Are we sure that 24mm isn't the correct size?

3) Should I be cramming these things into the manifold or into the passages on the engine? I've always put them in the manifold before, but now that I think about it that's kind of dumb. If I put them in the coolant passages in the engine then I could remove the manifold without any coolant mess at all. Is it okay for me to pound these freeze plugs into the coolant passages on the 12A?

Commence discussion. :D

Jamie

Freeze plugs friction fit in the hole, quarters cover it. Put the plugs in the housings, then one doesn't need to drain the coolant down to remove the intake mani.

Ok, so if I'm actually going to hammer them into the engine then 20mm is what I want. Right? Is a socket extension, a deep well socket, and a hammer a bad way to go about installing them? That's what I was planning on using...

^^

And just to add on, I did the silicone/quarters and it lasted a while. I think when I
was removing and replacing the manifold a few times it broke the seal on one and
had a slow leak.

Word of advice, with freeze plugs or quarters, reuse the O-Rings! That is what
saved me from a slow drip.

you just need a 10-inch 3/8 drive socket extension. the end of the extension that attaches to the wrench fits perfectly in the plug. just hammer it in. gently

edit: this is what i used
https://www.rx7club.com/1st-gen-archive-71/cooling-intake-how-install-freeze-plugs-532565/

I use J-B Weld to seal mine. A thin film between the plug and housing, then a bead around the edge after seating. Round end of a socket extension or the right sized socket and extension works fine. Be careful seating them. They need to be inline with the face and it's esy to drive them too, then they just fall into the passageway and stay for life.

^This is exactly how I did it on the 12A.

If you can find them, there is a 20mm diameter by 12mm deep freeze plug that the local Napa here used to stock that worked awesome.

1.2 mm deep, can't see them being 12 mm. Part # is 101-505 0r 505-101. Made by Dorman.

Use Permatex #2 sealant on the freeze plugs. Install them into the engine, not the intake. And yes, use the supplied O-Rings With the new intake gasket for added security incase the freeze plug doesn't take. Make sure the coolant level is below the coolant holes so you can thoroughly dry the bore before intalling the plugs w/ sealant.

nope, I did mean 12mm. Driven in until the edge is just below the gasket surface, leaves a very nice valley to fill with devcon/jb weld/your putty of choice. No o-rings are required to prevent the "slow leaks" some people experience.

In all reality, it is a matter of skinning cats...

I used coins in my 12a and jbweld.

I installed 20mm freeze plugs from Mazdatrix in several engines. The ones installed with a little bit of RTV didn't leak, and it acts like a low speed lubricant making installation a little easier. On the ones installed dry, they tend to have a very slow leak so you still have to use stock o-rings. I use o-rings on the others just for safety.

+1

I used high temp RTV to seal mine up and its working fine, no leaks.

I didn't use any kind of sealant. No issues. Can't recall if I reused the O rings or not, but I've had the manifold off a few times since and never a trace of coolant. Maybe I just got lucky? :)











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