[Mgs] clearing the drains in the heater system

[Paul Hunt]

The slit in the end of the tube is to prevent fumes getting drawn up from 
the engine compartment into the heater system and thence the cabin.  It was 
also fitted to 80s and 90s Metros, at least.  Whether the bulb on the end is 
to squeeze gunge out or not is a moot point on the MGB as it isn't that easy 
to get to.  And in any case you could open up the slit simply by pressing on 
the sides of a plain tube, the bulb perversely makes it *less* likely to 
eject gunge that way as it will hold a larger lump.

Look in the air intake, if you can see water lying there the drain is 
blocked.  If not then pour some water in and see if it runs out immediately. 
If not then it is partially blocked.  The drain is at the right-hand end, 
and bit of 1/4" or so dowel poked in should locate the depression which is 
the top of the tube.  Photos here 
http://www.mgb-stuff.org.uk/heatertext.htm#airb
Much easier to clear from above, unless getting a face and arm-full of 
rotting vegetation and insect life floats your boat.  Once you have the 
dowel through pour clean water in from the top until it runs clean from the 
bottom.

PaulH.

----- Original Message ----- 
> No that does not make sense !  The drain tube goes up to the intake so no
> exhaust fumes there. The bulb is probably there to allow a "squeeze".