Technical Water Pump - Different Number of Vanes

[Max P]

Hello everyone,

I have recently been working on replacing the head gasket in my Fiat Brava (1.2L, 16v, petrol, 182.B2.000). While replacing the head gasket, I figured I'd replace a few other things while I'm in there including the timing belt and water pump (and many other parts).

When I went to put in the new water pump on Saturday, I noticed that there were only 6 blades/vanes on the new impeller instead of 8 on the one that I removed. I also noticed that the diameter of the new impeller disc was 5mm smaller than the original one that was in there (57mm instead of 62mm).

Will this be a problem? I presume that the output of the pump is dictated by the rotational speed of the impeller as well as the number of vanes on the impeller, but since the pump is run off the timing belt, it will be running the same speeds as the previous one, and so I would have thought that it would not be able to provide as much pressure as the original one.

I would be very grateful for any help on this!

 

[Max P]

P.S. While working on the Brava, I managed to damage two bolts. If anyone has spare bolts lying around from taking apart various Fiats (or other cars), I’m looking for one M5 x 20 Torx socket head bolt (I think it has a T25 head), and also one M6 x 24 flanged hex head bolt (10mm hex head). If anyone does have either of these bolts, I could paypal them the money in return for the bolt. The first one is from where the stepper motor attaches to the throttle body, and the second one is from where the water pump attaches to the block.