Very basic question... If I were to have my thermostat removed, and the engine running, should I be able to visibly see the coolant circulating through the radiator? I removed my thermostat and with my engine idling I see no coolant circulation through the radiator (looking through the cap)

 

nope! every car has a bypass, so when the thermostat is closed the water pump still pumps water around the block.

when the thermostat opens, it plugs this bypass.

if you remove the thermostat, the bypass is open, there is no reason for the water to go thru the radiator.

either put a thermostat in it, or plug the bypass

 

I'm not 100% sure but I believe it depends wether or not you cover the bypass passage, which is visible directly below thermostat when removed. This is because water will bypass pump and not give the pump a positive feed.

 

coolant is fed into the radiator to be cooled from the lower hose and rises upwards. coolant is only let into the engine when the thermostat opens at its specified temperature. since the water pump only circulates coolant through the engine and helps to create pressure, there should be very minimal movement in the coolant in the radiator, even with the t-stat removed..which is never a good idea and will cause the engine to overheat and ultimatly, to fail.

 

what's the reason to seeing the water flow anyways? If you want to see it flow, leave the thermostat in there till the water get up to temp, then rev it and you should be able to see it flow across.

 

or feel for the upper radiator hose to get hot when the thermostat opens.

 

OK, let's clear a few things up here.

The cooling flow is top to bottom in the radiator. The bypass allows flow inside the engine until it's warm enough to open the thermostat. The bypass is much smaller than the radiator hoses. With the thermostat removed, there will still be flow to/from the radiator.

Now, the real question is, 'Why was the thermostat removed in the first place?'. What is the real issue you're dealing with?

 

my car runs hot with the thermostat installed and everyone keeps telling me to remove it. i have a big aluminum radiator and its shrouded and everything. im debating removing it to see if it fixes the problem but you make is sound like a bad idea... im so torn

 

you can remove the t stat, but the bypass needs to be plugged if you do.

its a pretty big passage, but i bet you could find a freeze plug that would fit...

 

Or, buy a true Mazda thermostat. If that doesn't work, then start looking at the water pump. No reason for the engine to overheat with an after market radiator and proper shrouding. It's either wrong/bad thermostat, water pump impellers worn, or fan isn't working correctly.

 

or a faulty coolant seal or corroded coolant seal seat on the rotor housing...