I used the Steel Seal on my DOHC W/ bad HG's.
It helped, but by no means fixed it.
I never had it raise the temp gauge after I put it in, but the bubbles were still coming out. It was a quick easy way to get a couple more months out of the engine until I could afford to do the gaskets.
Here's the bad part. After I pulled the engine to the job right, I found a ton of gunk clogging up the coolant passages.
The Steel Seal website says it won't clog passages or adversely affect the engine. I call BS. What I found when I pulled my heads of was very bad.
There's no way I would use this stuff again.
The coolant passage where the leak was, was totally filled with the solids that the Steel Seal turns into.
I can't even explain how bad it was.
Sorry I didn't get to you with the info before you dumped that junk in.