why 90 degree's???

[kane1210]

Engine temp 90. was driving home today and wondered why 90, my s3 was this temp as well im sure most cars are. Anyone know why??

[ifti]

Because 90 is just right

[icenutter]

I do know that the gauge lies.  On VAG cars the actual water temp can be about 10^o out and it will stay at 90^o.  I guess it's to stop people being alarmed.

[joesgti]

I do know that the gauge lies.  On VAG cars the actual water temp can be about 10^o out and it will stay at 90^o.  I guess it's to stop people being alarmed.

what!? thats stupid, if thats the case then there is no point in even having the gauge in the first place!? 

[bacillus]

I do know that the gauge lies.  On VAG cars the actual water temp can be about 10^o out and it will stay at 90^o.  I guess it's to stop people being alarmed.

This^^^ is true as there is a dead zone at the 90C mark if you check with vcds.

[carl1]

if it was 100c it would boil

[bacillus]

if it was 100c it would boil

That is incorrect as the system is pressurised thus raising the coolant boiling point...

[carl1]

if it was 100c it would boil

That is incorrect as the system is pressurised thus raising the coolant boiling point...

well thats something new i have learned today

[Egbutt Wash]

Both the pressure and the ethylene glycol raise the boiling point.
An atmosphere or so pops it up by about 25C and the antifreeze perhaps another 12C
Giving nearer 140C as the boiling point of the stuff in the cooling system.

[stealthwolf]

Giving nearer 140C as the boiling point of the stuff in the cooling system.

Which, IIRC, above the max temp on the guage.