| 415 GTS104 
thermostat - vented or not?
 A post on the V8BB asked whether the 
thermostat on an RV8 should have a vent. Tthe parts manual lists the thermostat 
as GTS104 and service repair section of the RV8 Repair Manual AKM7153ENG 
sets out the procedure for replacing the thermostat. The thermostat is mounted 
horizontally and a note specifically says "fit the thermostat to the housing 
with the vent pin in the 12 o'clock position - caution, failure to position 
the thermostat correctly can lead to air locks and overheating".
 
 Nic 
Houslip explains in the full version of this note that "the small drilled 
hole is a bleed hole, primarily to allow a small amount of heated water to go 
past the thermostat and ensure that the wax bulb gets heated and allow the thermostat 
to open, it also allows any air trapped which may also prevent the
 |  bulb 
getting heated. The bobble valve allows a reverse flow of water during cooling 
down when the thermostat may be closed. You need to check carefully the replacement 
part has a vent".
 
 The thermostat for the MGBGTV8 is also a GTS104
 |  with 
the vent in the 12 o'clock position. When you buy a replacement part it's essential 
you check for the presence of the vent pin and to reject any thermostat 
supplied that does not have one.
 
 See the full note at RV8NOTE451.
 |