test shows positive for head / head gasket problem. Fix with sealant

[oz16us]

so today, my sport trac began to overheat... but i turned it to heat and the temperature quickly came down. I pulled up to the drive way and used the block tester on my coolant reserve and got a positive reading. I guess I have a head / head gasket issue. It guess I'm double wrong again... the red stuff in my radiator could be flakes of stop leak or even rust... either way, the crack in the head or head gasket must not be big as I had a hard time getting the block tester to show positive. This was the first time after 6 tries

Right now, I can't afford to get it fixed the right way, so I have no choice but to put some head gasket sealant like kseal. But I'm curious to know when it comes to faulty head gaskets, do they open up one day and seal up the next? I had a hard time replicating symptoms ....it doesn't consistently overheat

 

[JohnnyO]

When faced with a problem I always begin with the cheapest fix first.
In other words [$ block sealer < $ new head gasket], i.e. it's worth a shot.
I don't remember if Gen 1 Tracs have the tranny cooler built-in the radiator or if it's separate but it's possible the red stuff is tranny fluid if the cooler is built-in.
In which case you may be lucky and just need a new radiator.
But I could be wrong.