Use gt3 water pump with metal impeller?

[JFP in PA]

Originally Posted by Smallblock454

If a failing water pump with metal impeller grinds into the case house, you'll have metal in your water system - means water cooler and hoses.

Not in the engine oil system or inside any moving parts or bearings! It's just in the water channels or cooling lines or water coolers.

Same to plastic parts.

The question is: are fine metal parts better or not so fine plastic parts.

After some thinking i would prefer fine metal parts.

Regards, Markus

They both can block critical small passages, leading to hot spots. The major difference between the two is the permanent case damage metal impellers can do, which leads to cooling problems even after everything is cleaned out. Clean out the plastic, install a new pump, and it is as though nothing happened.

[Smallblock454]

Originally Posted by JFP in PA

They both can block critical small passages, leading to hot spots. The major difference between the two is the permanent case damage metal impellers can do, which leads to cooling problems even after everything is cleaned out. Clean out the plastic, install a new pump, and it is as though nothing happened.

Considered this aspect.

Problem is that the plastic parts in general are much bigger than the metal parts. OK, thin metal parts could affect the bearings of a new water pump. Big plastic parts can block thin water lines. And as we all know there is not only clear fluid in this lines. Over the years we get some corrosion and other dirt - even it's an aluminium block (and there is also aluminium corrosion).

Still on the metal impeller side.

Regards, Markus

[JFP in PA]

Originally Posted by Smallblock454

Considered this aspect.

Problem is that the plastic parts in general are much bigger than the metal parts. OK, thin metal parts could affect the bearings of a new water pump. Big plastic parts can block thin water lines. And as we all know there is not only clear fluid in this lines. Over the years we get some corrosion and other dirt - even it's an aluminium block (and there is also aluminium corrosion).

Still on the metal impeller side.

Regards, Markus

You are overlooking the fact that even very small metal bits can agglomerate into passage blocking as well. We have seen it happen. And the case damage from the pump hitting is also permanent, which reduces the overall coolant flow in even completely rebuilt engines, so you have a fresh engine starting off with one hand tied behind its back.