My system does not need/use the HP500 "steam port" (see picture). I used a high temp silicone end caps (with hose clamps) to "cap" the port BUT one end cap inflated like a small water balloon...so I need something more robust.
I am going to pre-load the end caps with silicone sealant for now but I would like some first-hand knowledge and link to what others have successfully used.
Thanks,
Tom

Why wouldn't you cut them off and weld a flush patch in and polish? Like it was never there.

Thanks, I was hoping to retain them in case they became useful with future mods.

Have you tried coolant bypass caps ? They are used to cap off unused radiator ports on vehicles.
I’ll bet $20 they are tougher than what you used.

I’m not sure what size you need, but this brand get’s good reviews:
https://www.amazon.com/product-reviews/B083QJNNBY/ref=cm_cr_othr_mb_show_all_top?ie=UTF8&reviewerTyp e=all_reviews

copy/paste above link. I guess oso won’t hyperlink it. Lol.

That is what I'm talking about! Now that I have the name (Coolant Bypass Cap) many styles/sizes show up...Thanks!

Stay away from Dorman caps, which is at most part stores. Cheap schit that falls apart

I feel the same way and bypassed them when they came up in my search.

How's everything running? All good with the reversion issue?

Seems like new hi-risers and thermostat for oil cooler resolved my issues.
Ps-It's getting perfect weather for boating and SLs!

Glad she's all back together and working well!

And yes, 70's this week in Hampton Roads - yesterday was a top-down, take the long way to work, kind of day. Going to drag the boat to the ramp this afternoon to get the idle under load worked out, too.