Waterpump installation

[Spikes]

Read something interesting in the 60 yr Anniversary issue of CAR last night.

When installing a new water pump it is recommended that the impeller should NOT BE SPINNED at all before installation. The seal on the shaft is designed to run wet. Dry spinning may cause damage to the seal lip. If you cannot resist the temptation to spin the pump, do it in a bucket of cold water. 



 

[kleynhap]

Spikes I would take that with a pinch of salt.

Yes, mechanical seals are supposed to run wet, but I doubt that hand turning the impellor at hand speed, and for probably not more than 20 revolutions (?) will create any wear or heat build-up to cause damage prior to installation.

However it definitely applies to something like a boat's outboard motor - some guys like to dry start their engine before launching (in fact I think its a requirement for a Skipper's license). In that case, when the motor fires and idles at ~ 800 rpm even for only 30 seconds, the damage potential is vastly different.

[Spikes]

It puzzled me too,  Peter,

Lots of diametrically opposed views

https://www.mossmotors.com/forum/forums/thread/8841.aspx

https://www.gatestechzone.com/en/problem-diagnosis/cooling-system/water-pump-failure-signs

Personally I agree. Turning it by hand should not damage the seal lips to that extent.

[Danie]

There is no chance that a new waterpump will spin "freely" by using your hands. You can try as many times you wish - new water pumps are just a little too "tight" to spin "freely".  It can only be turned fairly slow by hand, and always simply stops turning immediately when you take your hand off the impeller, or driving shaft. I think chances that seals could be damaged by turning a water pump that slow, are about zero.

[ram]

No seal, wether it s designed to keep coolant, oil or Grease inside, should be run dry. It should always be lubricated with the substance or liquid it s supposed to keep in, prior to being put to use in normal working conditions . In the case of a waterpump it s automaticly done by refilling the coolant after installation.
I fail to see the purpose of spinning the pump by hand. In any case, it Will not spin freely and it Will be close to impossible to damage the seal by turning the impeller by hand. Maybe, just maybe, if it s a NOS pump, that s been lying in a corner for many years, of which the seal has become brittle....