Coolant - When and How to Top Up?

[Pat]

1990 Miata A/C STD.

I have never topped off the coolant in my Miata. I noticed that the
reservoir level was at the LOW reading and the engine was hot after driving
30 miles.

I am not familiar with closed systems and when you need to add coolant. I
called a Mazda dealer and the service rep said I should never open the
radiator cap, hot or cold. I should only check the reservoir tank and do all
the topping off there. He said its normal for the level to be LOW when the
engine is cold. He said the level usually goes between LOW and HIGH during
normal opeation with the engine running. However, if the coolant is reading
LOW, when the engine is turned off but still hot, I should top it off.

What is the procedure for determining you need to add coolant?

Where do you add the coolant. Reservoir or Radiator?

What should that coolanat be? The Miata shoip manual says to only use a
mixture of distilled (or demineralized) water and ethylene glycol
antifreeze. Why is there not a premixed solution rather than having to mix
it yourself? For the summer, what should that mixture be? If I just need a
quart to top off, for example, can I just use water?

Thanks in advance,

Pat

[DFind89379]

Anti-freeze is available pre-mixed, but usually you find it in auto parts
stores full strength. You should add only to the reservoir, not the radiator.
You can probably get by with just adding distilled water. You won't be adding
enough to affect the coolant ratio much. At any rate, do it today. If your
level only reaches the low mark when hot, the system is probably sucking air
when it cools down. Don't worry. After you restore the level, the air will
purge out after a few heat up-cool down cycles. Oh, and buy the green
anti-freeze.

[Chris D'Agnolo]

I wasn't aware that Mazda recommended the distilled water, but I have heard
that it will make a radiator system last and last and last. Don't deviate
from that.

Dagger
92BB&T

[John Smith]

Is it okay to use plain tap water rather than distilled? The water in
my area
doesn't seem to be very hard (no visible deposits in my fish tank
anyway).

And to the original poster, make sure you buy coolant that is safe for
aluminum engines.

[Marc in Oz]

Definately not!!!

Use only distilled water if you want your engine to last more than another
year.

Marc

John Smith <John...@hotmail.com> wrote in message
news:3AF32A0F...@hotmail.com...

[Tom Howlin]

First, if you've never topped off the coolant does this mean you've also never
changed it? If that is the case, you seriously need a flush and refill.
Coolant should be changed out every two years. If your coolant is the original,
it has lost much of its capacity to resist boilover and freeze up as well as any
corrosion protection it ever had. The radiator may actually be clogged with
mineral deposits by this time. I would start with a at home flush and fill
(dispose of the anti-freeze properly - PLEASE) and then check the coolant level
and operating temperature for a couple of weeks afterwards. If you have changed
it recently, then forget the rest of this and add a 50/50 mixture to the
recovery tank to bring it just above the low level when cold.

Tom
92 Red
95 SC-M

[Mallamj]

Distilled water is preferrable, but the point is to use water which does not
contain chemicals, such as the chlorine commonly found in municipal water
supplies. If you have access to a well which is used as a potable water supply,
that water would also be chemical free. However, it may not be exacltly pH7,
depending on the soil chemistry near the well.

[Pat]

If its at LOW while engine is hot, then I need topping. Right?

I am going to wait until the engine is cold. At what mark should I top off.
The FULL mark? Or half way between HIGH and LOW? I guess I am trying to
factor in the coolant being hot and expanding but how do you estimate the
expansion when the engine is cold?

Pat

"DFind89379" <dfind...@aol.com> wrote in message
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