1990 200Q radiator blew up

[tom winter]

The bubbles that you mention plus the fact that the cooling system seems to
be subjected to abnormally high pressure makes me think your friend is going
to be pulling the head and doing some major surgery (valve job, water pump,
timing belt, new head gasket, etc, etc). I'm guessing that Keith has a good
idea here: Warped head or blown/bad head gasket. Pressure (as you guessed)
being dumped into the cooling system. Any coolant in the Oil? If so, don't
leave the car parked too long before starting repairs. Coolant can be
corrosive to the bottom end. You'll want to drain that s**t out soon.

Tom