I'm trying to drain, flush and re-install the coolant as we speak (type )! I'm having trouble getting all of the old
fluid out and when re-filling getting all 7.3 liters of the coolant mixture back in!

I know about the drain on the bottom of the radiator and the block drain in the intermediate housing, but when I try to refill the system, it only takes about 5 liters. When I start and run the engine and it gets to temperature the coolant level in the rad still does not drop? I'm waiting for the engine to cool so I can check the thermostat to make sure it actually opens, 'cause it's the only thing that I can think of thats preventing the fluid from flowing and therfore trapping an air bubble behind it.

Any thoughts? What's the secret?

 

Did you open the bleed screw? You won't be able to fill the ENTIRE system because some old coolant will always remain, so just fill it until it will not take any more. Also, bleed as per instructions in the Hayne's or factory manual.

Also, I find it beneficial to manually "burp" the system by holding my hand over the fill hole, and then squeezing the rad hose a few times....It circulates coolant and tries to get rid of any air pockets.

 

Aaron, I don't see the bleed screw listed in the FSM...

Can you provide the location?

Also tested the thermostat, even in boiling water it only opens about 3mm, FSM says 8-10mm minimum. would you aggree?

Thanks

 

'91s might not have the bleed screw due to the different location on the filling hole...I don't have one in front of me so I can't check...

However, it is located where the upper rad hose connects to the rad...

If the thermostat only opens 3MM, replace it. In fact, you should replace it every year with a genuine Mazda replacement only.

 

I looked at my rad and there isn't one there, but as you say the filler neck is pretty high up already.

As for the thermostat, I guess that you don't recommend the one on sale at Canadian Tire? Are they really that different?

Thanks

 

Nope, only Mazda thermostats are to be used.

If you don't have a bleed screw, do as I suggested and squeeze the hose manually while you cover the filler hole with your hand. It will help get rid of air pockets....May take some time.

 

CT is out of stock anyhow (saved?)

Al

 

those extra couple liters of fluid may well be in the heater core... no biggie! If you wanted to flush it, you could probably fill the whole thing with just water and the idle the car for a few (<5) minutes to circulate the old crap and then drain it again -- that should help get most of the old stuff out. Make sure the heater and fan are ON when you do that. After you're done with that (If you want to do it in the first place), just put in a gallon of prestone antifreeze, top it off with water, put some in the overflow tank, and drive that thing The air bubbles should work themselves out no problem.

Have fun ,
Manolis