'89 525i Overheating

[Savra]

I currently have a 1989 525i that's exhibiting an overheating issue. Temp will run to red-hot after about 10 minutes of running. Has not had a thermostat installed in the 8 months I've owned it and it hasn't been an issue before now, the head gasket was done on the day I bought it. The head bolts were retensioned, although they didn't have new head bolts. When the cap is off the rad reservoir, it alternately rejects water and noisily sucks it, bringing up air as it goes through. One of the top rad hoses (the uppermost far left) shudders when the rad is force flushed with a hose but no block is apparent. There's no water in the oil or oil in the water, and we just replaced the water pump within 24 hours and it still hasn't fixed it. The old water pump had a weephole blown in it, hence prime suspect. Thermo not attached as wiring seems to be screwed, and would overheat immediately when it was in 8 months ago. Any help appreciated, we're pretty much at our wits end - everything says head but I don't want to have to go to that extent when it doesn't seem to exhibit the telltale signs (no mix of oil/water, no fluid around head, no steam or noise from engine).
Any ideas welcome! :idea:

[Dj Buttchug]

it sounds like the engine is pressurizing the coolant system so the head gasket is toast. Whoever did the job must have made a mistake somewhere.

[slammin.e28]

The head bolts were retensioned, although they didn't have new head bolts.

M20 should have used new headbolts. Didn't read past there.

Bollocks, you're going to be redoing the HG.