I've been looking at new water pumps. The impellers on some are made of sheet steel spot welded to a circular backing plate. I also found some made of cast iron. I'm going with the cast.

What concerns me is the circular backing. On some pumps there are holes or slots in it. Others are solid. I'm trying to determine whether the ones with the holes or slots were hd, or the other way around.

Maybe I should find a better parts house. Remember when they actually read books, before all the info got homogenized through a corporate computer?

Does anyone know anything about this?

 

I have the same problem. Old pump has triangle slots in the impeller. New pump is flat.
I am trying to find out if the flat impeller is part of my new engine overheating. Any ideas?
my engine is a mid-seventies block. Rock auto shows different pumps for with and w/o thermactor emissions.
Would that have anything to do with cooling?
Thermactor pump has triangles; w/o thermactor is flat on back of impeller.
Both have stamped steel impellers.
As always, many thanks to all.,...jack

 

Jack, I searched and searched for info on this, and came up empty handed. It seems some guys target the cast impellor models and believe they are superiior.
That may be. I don't know. What I know is that I ended up going with--due to time constraint--with an Auto Zone $35 stamped steel impellor model.

That was eight years ago! It has fins perpendicular to a round plate. It moves the water well. Never had a problem with over heating. However, all these years I was afraid the fins might be deteriorating since they were thin steel plate.

After eight years it began to leak and I replaced it (free under warranty!). I was very surprised to see that the fins I was worried about looked as clean and pristine as the day I put it in.

If your w/p doesn't have slots or paddles to move the water I'd replace it. It could be a factory defect.

I'll throw out a bit of info I gathered somewhere. I don't know what your vehicle/engine year is, so I don't know if this is relavant: The efi year water pumps spin the opposite direction as the V belt w/p's do.

Good luck.

 

I've always had the style that is the circle disc with the perpendicular blades and have never had a problem with them.