On Wed, 12 Aug 2009 12:43:57 +0100, Stephen
wrote:

We have got a Panasonic combined oven/grill/microwave so I don't think
it's necessarily cheaper to throw it away rather than get it repaired.
The other day we saw some steam coming from under the door. I looked
and I am sure it came from under the door rather than a vent under the
oven. So my worry is, if steam can get out, can microwaves?

No, a microwave oven uses a rather cunning trick to make it sealed to
microwaves without requiring a precision fitted door with contact
seals.

It is called a "choke seal" which is a non-contact seal and very
tolerant of misalignment, gaps, and even dirt.. It depends on the
relationship between the dimensions of the oven surround and the oven
frequency (of 2.45GHz ).

The door's "microwave seal" should last forever if the door and the
adjacent oven edge surface are not mechanically damaged and the door
hinges and latch don't grossly shift position. A visual inspection is
all you need to do.