What exactly happens to the water pump when it cavitates? What does/doesnt it do? I searched but did not find an answer to this.

 

The water that is passing the water pump fins starts to cavitate, meaning that it isn't flowing as it should and is really just churning instead of flowing through the radiator as it is supposed to. An underdrive pulley will correct this if it is a problem.

 

I can give you a more technical explanation of what is happening...

The impeller is turning so fast through the fluid that the fluid actually BOILS at the tips.&nbsp This in turn aerated the coolant - aerated coolant is a BAD thing because these tiny bubbles (when heated) expand causing air pockets; air pockets are bad!&nbsp Aerated coolant and air pockets decrease efficiency of the impellers ability to move coolant - did that make any sense?



-Ted

 

Nice answer Ted!

 

That's what I said, but in English! LOL

 

Thanks!!! Could these air pockets force coolant out into the overflow reservoir and on to the ground? I took my filler cap off and saw little bubbles while the car was running. But water never gushed out of there. So I was thinking my coolant seals are going (the hottest my car has ever gotten is 3/4 on the gauge). My air pump locked up a while back and the belt broke. So I've been running on one belt on the water pump ever since. SO now Im thinking my seals are fine but its my water pump thats screwy. I asked my local rotary shop about coolant seals and they said "if your seals are going, the car would spit out coolant after 5mins just sitting there". My car doesnt do this. I fill up the coolant once a week. Any ideas of whats going on here?? Didnt mean to bore u guys with my life story

 

You really can't run the water pump on one belt - this is the reason Racing Beat makes a double-sheave alternator pulley.

Easy test to see if your water pump is slipping...grab the water pump pulley and turn, if you can do this by hand, it's slipping!

This is most likely why you are overheating!



-Ted

 

Hunt for Red October is one of my favorite movies!



-Ted

 

thanks! I'll check the water pump pulley and hopefully get a double belt pulley on my alternator in a week. Should I replace my water pump too? Water isnt coming out of the weep hole as far as I can tell. I was just wondering if something got messed up since Ive been running on one belt for a couple of months now. Thanks again!

 

The specs for testing the water pump are in the FSM, and if you don't have one, there is one in PDF for both models on my site under How-To's and then under manuals.

If you need a new one, check out www.mazdaformance.com. They are only $56. Ask for Brian there.

I also juse replaced mine in my vert, and am doing the write-up for it as we speak. I will post another thread when it is done.

 

No air pump. Do you have cats. Reason I ask is clogged cats (common w/ no air pump) will cause alot of heat damage to engine and seals over time.

 

I have a RB Pre-silencer in their place.