New Freeze (Expansion) Plug Type

I didn't even know these existed until a couple weeks ago but I figure since I have the heads off and at least one looks like its been starting to corrode, I'll replace the ones I have access to.

Learned about an hour ago when creating my gasket cart that they come in brass and steel varieties. Naturally I googled what the benefit of one over the other is and which is better. Took me to some older truck forums that almost unanimously said brass were better.

However it occurred to me that they all probably were used to iron blocks, whereas we have aluminum. And knowing the bit that I do about galvanic corrosion, aluminum hates everything, but hates copper (brass) more than steel. Thus, I should go with steel plugs. Sound right?

 

The 1995-2004 Tacoma uses iron blocks for both the 4- and 6-cylinders, as do the 2005-2021 4-cylinders. Only the 2005-2021 V6 has an aluminum block.

Jeff

 

Oh, really? Oops

 

Ok well the head and valve covers are aluminum, I just tested with a magnet. So back to the original post..

 

I’d still go brass no matter what. Soft enough to get out if you need & the Brass properties lend them to do what there made to do. Expand & pop when frozen.

 

Yeah, there's plenty of aluminum on the engine for sure (and the newer aluminum blocks don't actually have expansion plugs on them). I was just thinking you were mainly looking to replace them in the block. Each head has four 30 mm plugs I believe.

I've never used anything other than steel plugs, whether I am installing them in iron, steel, or aluminum. Ditto for what Toyota uses across the board. I think most people's complaints with steel plugs are when they use super cheap uncoated and/or non-stainless plugs that rust out. I've never had that happen with a Toyota plug, so I just keep using Toyota plugs.

Jeff

 

Doesn't properly maintained coolant prevent (or minimize) galvanic corrosion?

 

Ya, it helps. Ideally you would never mix metals and it wouldn't even matter, but coolant isn't perfect and I tend to run only 30-40%

 

I'm just gonna get steel since they're local for $0.76 a pop

 

Apparently it was a lie. These are apparently not a popular part. Nobody carries the right size. Even rockauto has the wrong sizes listed.

Should I pop out the old ones and apply a sealant and reuse, or just leave it all be?

 

Why not just grab them from Toyota?

Jeff