How to change coolant?

[Thestef]

Hi guys,

I know were the drain plug is, "at the bottom of the radiator" but do our cars also have a drain plug on the block of the engine?

I'm doing a coolant change/flush on my car this weekend.
I'll be searhing for it underneat the car, but if I know were to look it will save me lots of trouble.

Thanks!

[perhapsadingo8yerbaby]

Can't figure from your post or profile what model MX/engine you are asking about. My 1995 B6 & K8 Mazda shop docs don't mention or appear to show an engine block drain from what I can see though & I've never found one when flushing my system.

In any case you're doing a flush so wouldn't need to open one on the block to ensure a complete evacuation right? Just be sure to flush under full circulation conditions w/thermostat open and heater on high til exiting coolant runs clear. Then add your antifreeze (by pre-measured volume) for desired % coolant mix then top up rest of the way with H2O. Hope that helps...

[Thestef]

I have an 1993 SOHC,

So? once I remove the drain plug from the Radiator, should I leave the engine running and let it drain.. or should the engine be left off wile its draining?

I would think that coolant would still be left in the engine if you just remove the drain plug on the radiator?

I though there might of been a drain plug on the engine block somewhere to make certain all the old coolant was evacuated.

[Gro Harlem]

there isn't a drainplug on the block. i odn't think any cars ever had that.

when you drian your radiator, your supposed to do a flush. What I do (b/c i'm lazy) is just drain the radiator, start the car (with radiator empty) then once it warms up (watch the heat gauge inside the car) it'll open the thermostat and all the crappy coolant inside of the engine will being to flow out. Remove the upper radiator hose from the radiator and let it drain onto the ground (or a bucket if you care about the environment). Then while thats draining, spray water into the radiator (which will flow downward into the inlet for the water pump).

You'll see the crap coolant coming out of the hose start to look like water. When that happens shut the car off & drain the radiator.

Fill that mofo with coolant & water to the proper mix you need.

This is the super-lazy-bastard way to do it, but it worked for me on numerous occasions.

[perhapsadingo8yerbaby]

Originally posted by Gro Harlem:
This is the super-lazy-bastard way to do it, but it worked for me on numerous occasions.

Thanks for posting that up Gro. I too use the super-lazy-bastard method but was debating whether to post it for Thestef because it can potentially be a bit tricky for the uninitiated if they haven't used it before. There, I said it. As for going by the book & draining the block, wouldn't be surprised if there is a drain plug somewhere around there, or even two like one of my old Mazdas used to have. Unfortunately, I've been a super-lazy-bastard for so long, can't really offer anything more specific on that though...

[Thestef]

Thanks for the help guys, just did an oil change, put in a new air filter and did a coolant flush.

I emptied the Radiator, then put in some coolant flush stuff and filled it up with water. I went for a 15 min drive. When I came back, I let the engine cool down, emptied the radiator again. Turned on the car until I saw some more coolant flush out of the radiator. Turned off the car, then put the plug back on the radiator, disconnected the upper coolant hose, put the garden hose in the radiator with low pressure, turned on the car and it started pumping out some coolant when it reached its operating temperature.
It cicled about 5 times, (the thermostat openned 5 times) and water came out, I had to rev up the engine a bit to get it to open the thermostat long enough for lots of coolant to leak out.

Anyway's, job done!
Thanks for the help


Ps: Sorry about the spelling mistakes, I'm in a hurry to finish up.

[Gro Harlem]

yeah, you basically used the super-correct-way-to-do-it method, but you probably spent about 1.5-2 hours just flushing it all 5 of those times.

super-bastard method pwnz!! takes like 15 mins & ruins the environment! :p

[perhapsadingo8yerbaby]

[quote]Originally posted by Thestef:
Thanks for the help guys, just did an oil change, put in a new air filter and did a coolant flush. Anyway's, job done! Thanks for the help