Perkins 6.354 Coolant Header Tank Question

[Alaska Californian 37]

I have two Perkins 6.354 engines with original Header tanks. On the front is a small circle that has become semi-permeable lol... I believe the circles are freeze plugs that have corroded, but ran out of time to drain the coolant and verify.

Can someone confirm that is or isn't what they are? I have to fly to where my boat is currently, and the more things I can pre-purchase the better.

 

[kapnd]

I think that’s a freeze plug, but Perkins does some wild stuff, so could be anything.
It’s obviously not aluminum, like the reservoir body, so it could be cause of corrosion.
Make haste to get it taken care of, that aluminum part may as well be gold if you need to replace it!

 

[STB]

It is a little hard to tell from that picture, but I think that is an NA001459 header tank. Replacements are available, I think made by Seakamp:
-- https://www.mrcool.us/na001459-perkins-aluminum-tank.html

On the ones I've seen, which have been newer, that exterior feature has either been entirely missing or a vestigial indented ring.

Based on that, I assume it was a plug.

Because I think those plugs must have been an early feature, I'm not sure you'll find a replacement. You may need to improvise or, depending upon the overall condition, replace the tank.

 

[kapnd]

If the tank is salvageable, that plug could possibly be knocked out, or drilled, and replaced with a SS freeze plug.
I’ve seen those with major JB weld patch jobs, even gasket faces rebuilt with it.

 

[Datenight]

How about a rubber plug? A quick check with Mr. Google gave many results. Here is one;

https://shop.advanceautoparts.com/c4/rubber-freeze-plug/-49997816

The rubber would also eliminate the two different metals.

Rob