[Vwdiesel] head gasket done but temp gauge still creeping up.

[Will Taygan]

94 Jetta with 1.6TD (originally 8v)

HISTORY:

Massive overheat, lost most coolant, air just boiling out of overflow,
pulled head, full head job done at independent VW shop.

(Obvious crack in gasket from #1 cylinder to coolant passage.)

Cleaned bock with the white 3M rotary bristles and engine
degreaser/brake cleaner.

Block had significant pitting near the coolant passages where the fiber
part of the gasket touches, metal contact surfaces looked good.

Dinged head when transporting home, also stupidly had a gritty oily zip
tie sandwiched in-between head and block when starting to tighten down.

Used ARP Cosworth studs torqued to 85, broke and retorqued 3x: 40-80-85.

Timed to 1.01mm, runs great, sounds like marbles when cold-start is out,
almost all the marble sound gone when pushed in.

I've got a veg-kit with extra coolant lines running to the trunk, tried
to purge these as well as possible.

Routed head to top of radiator hose UNDER veg lines when first started.
ooops.  The vent to overflow sphere doesn't work when it has to flow
down.  Started to overheat, shut it off, cooled it down, routed head to
radiator hose at ON TOP of system, blew some bubbles out, after 5 miles
things seemed to be perfect.  That overflow hose really likes to be up
high to purge air.

THE PROBLEM NOW:
Car is acting like there's bubbles in the system, gets to normal
operating temp, goes up one tick - especially on uphills, goes back down
on downhill coasts.

When overheating (I'm running with the coolant cap off - thinking there
is air in the system - I've tried with cap on, and it's similar) the
coolant bubbles up out of the reservoir.  While driving this isn't so
much of a problem, but fiddling with the system when parked I can do it
every time.  Is this standard on getting hot?  I'm thinking it's a sign
of air in the system.

There's not really significant air coming from the overflow hose,
occasional foam (I took the restrictor out to see if that make it purge
better), it seems to be pushing quite a bit of fluid.

The OEM water pump, aftermarket radiator and OEM thermostat are a year
old.  It always got hot on hills, but not on flats or while idling.

I'm thinking of running a compression test (check the head gasket) and
swapping out the thermostat - could overheating have damaged the
thermostat?

I'm fearing that my gasket job, while making the car drivable, may have
to be repeated (and I'm doing this in the neighbors garage.....eeeek!)

Will in Alaska.