Expert: Ben Deutschman - 12/4/2008

Question
Sent a previous question dealing w/this topic (weeping new water pump-95 JGC, L6,4.0).  Could too much pressure in cooling system cause a brand new water pump to begin to weep?  Drain cock valve is also seeping (out of end of tube, no pin holes anywhere) All of the sudden.  Its snuggly tight.  
    Prevously asked about viscouse (sp?) fan drive/clutch possibly out of balance (due to laying horizontal for a day) possibly causing damage to water pump.  No overheating, new l70 degree thermostat.  BUt did not reverse flush system before changeing the coolant out. So, too much pressure maybe?  Will change the cap tomorrow.

Answer
It is possible that the Pressure Cap is not venting at the stated setting anymore, and that  the system is being over pressurized. The amount of time it might take for the Cap to cause a leak, by not venting at the correct pressure, is something that would relate to how high the system pressure rises, before the Car finally vents the pressure. A back flushing of the coolong system would also help, in that it should help remove most of the sediment built up in the cooling system. I doubt laying a fluid driven Fan Clutch down, however long, would have any effect on it.