astra cooling temp - sajid
Regular reader may know that my astra operating temp used to climb to 97 and when around local traffic the temp guage used to jump to 100 before the fan kicked in.

It transpires that there was NO Antifreeze in the car and it's only recently that i filled it up with new antifreeze.

Now the temp gauge goes slowly to 90 and stays there unlike before, i thought antifreeze was used to warm the car quick ??

astra cooling temp - escort man
Good quality Anti freeze will allow the car to warm up quicker than water as the chemicals absorb the heat from the engine better. These same chemicals will radiate heat (cool down) better than water hence why it maintains a more constant and lower temp. (or so i believe)

Also stops your radiator from freezing in cold weather.

I take it your not using neat antifreeze as it should be mixed with some water. About 50% is the max i think.

astra cooling temp - David Horn
I believe one main purpose of antifreeze is to prevent the water boiling at temperatures close to and slightly above 100C.
astra cooling temp - NormanB
You may well be right - but for what it is worth I understood it only had two purposes:

a. Corrosion inhibitor.
b. Anti freeze.

The former is the most critical as without inhibition serious damage is done particularly to aluminum (normally cylinder head). This is why they recommend you change the inhibitor and flush the system periodically, as the inhibiting action reduces over time (2 or 3 years). Of course the anti-freeze job is important too but less so, those fortunate to live in areas without any danger of frost still use because of the inhibitor function.

The addition of inhibitor/anti-freeze also alters the 'wetting' performance of water and improves heat exchange.

To enable systems to operate above the boiling point of water they are pressurised - I think this has more of an effect than the addition of inhibitor/anti-freeze.
astra cooling temp - pmh
I would much more likely expect that either an airlock existed before (or does now) after changing coolant, resulting in a change of warm up characteristics.

Does the heater behave exactly the same as it used to?
Was the radiator cap changed, or does it now seat differently?
Was the engine radiator flushed, getting rid of the crud stuck in the thermostat? (or released crud to stick in it?)

pmh (was peter)
astra cooling temp - Dynamic Dave
You may well be right - but for what it is
worth I understood it only had two purposes:
a. Corrosion inhibitor.
b. Anti freeze.

I've heard that it can also help lubricate the water pump bearings as well.

Value my car