Bill, where are you measuring your pressure? If you measure in the block or at the pump outlet you’ll get unusually high, false readings.

With a 22 lb cap you can’t actually achieve 27 psi, as the cap will burp it to the over flow and reduce the pressure.

I suggest you measure the pressure from an expansion tank connected to the inlet side of the pump.

The stock Mazda cap is only 13 lbs … there is no reason to see even 22 psi.

JWW

 

 

 

 

I just recently got my Renesis started again after finishing my cowl.  I seem to be getting very high coolant pressures.  I can only run the engine about 10-15 minutes before hitting the redline at 210*.  My water pressure is at 27 Lbs at that time.  I only have a 22 Lb radiator cap, so I assume that I am blowing into the recovery tank, but I have not confirmed that.  My oil temp has never exceeded about 165*.  It might have gone higher if I could have run longer???

 

This whole water pressure thing has me a little baffled.  Since this is a closed system and the only way pressure can build is due to the expansion of the coolant after heating???, I am confused by some comments that have been made from time to time.  I remember something that Tracy said about his pressure would build for a time, then go to zero.  It seems to me that the pressure should correlate to the temp pretty closely since it is a closed system??

 

Can someone enlighten me a little on the science of this pressure?  It seems to me that there could be some pressure build up on the positive side of the pump, but it would go negative on the suction side, so the net effect of the pump should be close to zero??

 

Also, my Renesis had only 1800 miles on it when I bought it, so I did not have to tear it down.  As a result, I am somewhat in the dark as to how the water flows through the system.  Could someone help me with that?  I had to remove the thermostat tower for height clearance , so I made an adapter plate that takes water from the top outlet of the pump and sends it to the radiator (double pass), then from the radiator, it returns to the lower inlet of the pump.

 

Thanks,

Bill B

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