Suppose you replace a head gasket and the engine  is putting air bubbles in the coolant.  None in the Oil .  yet..

 Is retorgueing the head bolts got any chance of fixing that?

 or should I run Block seal in the coolant.

Whats your vote?   SC

Tiny bubbles in the wine,
Make me happy, make me feel fine,
Tiny bubbles make me warm all over
With a feeling that I'm gonna Love you 'til the end of time.

Its a toyota Van, 85 vintage.

S.C.   You would need some help with this . You could do a "leak down" test. This is a test where you check one cly. at a time under pressue from a in- house compressor.(engine not running of course)
   This would show you a couple of things, worn rings, leaky valves or in your case a leaky head gasket. Air leaking from the combustion chamber back into the cooling from a bad head gasket would try to pressurize the system.  Bubbles, gurgling sounds etc.
    I don't know about Toyotas, but Hondas do not like anti-freez running through places where its not suppose to for any lenght of time.  Combustion gases , anti-freez and Aluminum makes for bad bed fellows.  ACID. I looked at a Accord engine one time after about 3000 miles of a leaking head gasket.  The head, a few pistons were eaten up. The block wasn't anything to brag about. Pitted cly. bores.
    We use this test on early VW Diesels to run down leaks. worked for us.
    Better yet. Take the "critter" to a desent Toyota Dude and say FIX. :lol:

Don't loosen the head, just re-torque to factory specs and in sequence. I hope its not to late ,but  it sounds like it has already Blown out.  Does this engine have the "stretch" type head bolts ( bolts you torque up 1 Time and buy new ones when you have the head off for some reason) If you do have stretch bolts and try to re-torque ,you are taking a big chance that they might break off in the block. I don't know beans about Toyota, but I would find out before I got into big time trouble.

I think I would torque to specs. from where they are now.