dewey

The owner's manual for my P5 says to change the coolant the first time at 45000 miles and every 30000 miles after that...or something like that.

Why do you get to drive longer on the first batch of coolant? Is it because Mazda puts high-endurance stuff in there or something? Is it bad to change the coolant earlier than recommended?

On the page where it shows you how to change the coolant in the owner's manual, it seems to indicate that the radiator drain valve is on the *front* of the radiator, about halfway down (for the manual transaxle models). My visual inspection seems to indicate that the drain is actually in a more sensible location at the bottom of the radiator. Is the book just wrong? Or what gives here?

stealthscotty

The drain is at the bottom.
There is no harm in changing coolant sooner, but it may be a waste of money. Even every 30K miles may not be necessary. Test your coolant with a Hygrometer (Hydrometer?) to see what temp it will protect down to. Go to a parts store and ask for a coolant tester, $5-$10, and test it yourself. The tester will tell you how cold the coolant is good for. You need a reading of 20 to 30 degrees below your coldest winter temps.
The reason they suggest using it longer is the absence of the inevitable corrosion within a motor. Once the corrosion begins, it will contaminate coolant more easily. Remember to flush the system with each change and yu have no reason to be concerned.

carguycw

Ditto everything he said.

Also, a couple of other notes:
1) Use distilled water when you mix your coolant. I flushed the system and used distilled water and Zerex coolant when I replaced the coolant the first time at 40k miles, and when I changed the coolant again at 70k, the old coolant was CRYSTAL clear. It looked brand new! Highly recommended.
2) The cooling system should be filled SLOWLY. New Proteges use a reverse-flow cooling system (i.e. coolant flows through the engine from top to bottom) so the thermostat is located at the bottom of the engine, and it has an air bleed valve built into it. The engine should be filled SLOOOW to allow the valve to work and avoid trapping a big air bubble in the lower radiator hose. The service manual says to fill the engine at a rate no faster than 1 liter per minute, meaning it will take over 5 minutes to fill the whole thing!

Good luck!

dewey

The manual also says to run the engine while adding coolant. Does this mean you'll start out by running the engine with no coolant in it?

That gives me the oogies.

stealthscotty

a 50/50 mix of distilled water and antifreeze is best, so long as it provides the correct specific gravity to protect down to the desired temp. (use the tester) Distilled water alone will promote corrosion and offers no protection from freezing at all. Antifreeze alone will actually freeze before a mix would.
To refill after flushing the system, close the drain and fill to the top then start the motor to allow the water to circulate and push air out of the system. This won't be complete until the thermostat opens and then you'll see the fluid level drop suddenly. Watch out though, the water pump may over zealously push coolant back out the top of the radiator a moment later. When it's full and warm, close the cap and top off the resevoir. When the engine cools, any needed coolant will be drawn in. Then maintain the level in the resevoir to keep it at normal levels.

distance

Does the coolant have to be a little warm when you drain in order to drain more crap out like when you change the oil??? Need to know as I will be draining mine soon! Anybody try the RED stuff that GM uses (and or) can we!! Its almost stupid to use the stuff if you are changing out fluid at regular intervals anyways! Just trying to get a discussion going!

carguycw

First question: No. Change it cold. This is especially relevant on a Pro because the exhaust manifold is so close to the radiator that it's almost impossible to loosen the drain plug without brushing against the manifold, and running the engine for more than ~1 min. will get it REALLY freaking hot.

Second, I assume you're talking about Dexcool. This stuff works, but it's costly and cannot be mixed with regular coolant, so you have to flush the engine COMPLETELY to use it. Not worth it IMHO.

mp3wannabe

I have another coolant question:

my 01 has 27k on it and im about to install a cai so i was looking at the coolant resivoir, and it is almost on the bottom fill line. do i have to fill it up or will it last another 10k when i flush and refill it? does anyone know how long i have until it is empty?? i just dont want to fill it just to dump the brand new stuff back out.

MinnowGT

just top it off with some distilled water. <$1. It'll hold until your
next flush and fill. If you're worried you can add a bottle of the
above mentioned redline water wetter too.