hole behind w/p drain plug

[23jayhawk]

Never noticed this before, but there is a small hole (approx. 0.125" D) just behind the water pump drain plug. :eek: The surface is machined for seating a bolt or plug, but there are no threads visible in the bore. Is this just an escape path for overpressure behind the pump? Or is there a part missing? :think: Could not identify any parts in that area in the service manual. Anybody noticed this before?

 

[shr]

23jayhawk,

The hole is an atmospheric drain or vent to keep coolant from getting into the gear box if the mechanical "water pump" seal leaks.

If you see coolant dripping from this hole, the water pump seal is probable going bad. Any overpressure in the cooling system is released through the radiator cap into the over flow bottle.

Also if you were to see oil dripping from this hole, that would indicate that the water pump drive shaft seal is bad (this seal is a rubber lipped type and seals the gear box oil)

 

[23jayhawk]

Thanks, shr. Kind of thought it was some type of vent or relief. Probably ought to keep the gunk cleaned out of there so I'll know if there is ever a problem with one of the seals.