General Automotive Question:

Hi all,

I have a quick question which hopefully has a straigtforward answer:

How do you determine if your coolant is still good or needs topping up
with coolant or with water? My 240 owners manual gives values for
Specific Gravity but the coolant tester I picked up at Canadian Tire
tells me only boiling and freezing points (i.e. completely useless
since I don't know what range is optimal).

Is there some steady figure or method I should be working with? Also
my coolant is currently filled about half an inch above the MAX line
on the reservoir...does this matter?

I can't be the only one wondering about this, can I?

Thanks in advance,
blurp

 

Hi "Blurp",

You're lucky! My coolant tester has only a freezing point
scale.....but,seriously, that's all I want to know. That and the weather
forecast for overnight temperatures........... Apart from freezing
protection, anti-freeze has a limited life because of deterioration of
anti-corrosion properties of the additives. Some say two years.

As for your coolant level, I don't know the model year of your 240, but my
'93 coolant tank max. line is very close to the top. I wouldn't want the
coolant half an inch above that, especially when cold. I would suggest that
you simply remove enough to lower the level.

Good Luck.
Andy I.

 

Ok well even this is a big help. I know that all my coolant is at
least 4 years old, maybe older. I don't think the lugnuts at the
garage even checked the thermostat, they just went for the most
expensive repair on the list. I don't mind changing my rad if I need
to but not if I don't.

My problem, however, is overheating. I live in Canada so freezing is
an issue but it never goes to -45 and if it's frozen I'll take the
subway.

I'll be going after some answers tonight and let you know what
happens.

blurp

 

If your vehicle is hot, then the gauge will be over the "max " line.

This level should be measured when the vehicle has been sitting for a few
hours (cold).

hope this helps,
SC

 

by blurp dropped his wrench, scratched his head and
mumbled,

Unless you have a leak the concentration of antifreeze to water will be
essentially constant for two years. However the pH changes as the coolant
ages. The best way to measure the SG of a solution is to use a
refractometer. See
http://makeashorterlink.com/?A564319C5 for examples. The best way to
measure pH is with a test strip. See

http://www.acustrip.com/specs/3-wayafhd.html

for examples.

The same two types of tools are also used to ascertain the viability of
brake fluid as well.

If you stick to the recommended change interval of two years or 30K miles
testing is unnecessary.

Bob

 

<snip>

As a chemist, I have doubts about the pH reading. First of all, there is no
pH scale and no pH standards for a roughly 50:50 mix of water and ethylene
glycol. If one ignores that quibble, the most likely effect of long use is
oxidation of ethylene glycol to an acid. That would lower the pH, not raise
it, but the danger level shown on the Web page is 11 - which would be very
alkaline.