Hi guys,

Firstly I've checked out the tech section to try to find out what is going on to no avail...

Here's my problem.

My water temp sit's at about 80 degrees but only after a long period of warming up, and by a long period I mean 20 minutes...

Now as soon as I'm on the move - (even if it hit's 38 degrees in Sydney like the other week) - it will drop to 40 degrees after about a minute of running.

I've had 3 thermostats in there, had my gauge checked - everything is ok.

Should I be worried about running the car with the temp only at 40 degrees... sometimes even lower?

Matt.

Have you got the right thermostat in? I have seen some people have very low temp ones in and replace them by sample, and of course still have the same problem

i find that mine takes a little while to warm up... and cools very quickly when turned off...

and it runs at below 80degrees (c) even on warmer days.... i thought that it would run hotter than that with its tiny little radiator?

i havent driven it in the peak of summer yet though...

if i were u id be doing what dattodevil said and make sure u have the right thermostat...

mine runs cool but never that low...

i talk in farenheight.. mine sits at 180 or about 175 all the tme and 182 when freeway. only when weather is above 28deg c and im sitting in traffic or with the lights ondoes it rise to about 190 (90 deg celceius).
40 sounds too cold.

40 deg. centigrade is 40 x 1.8 = 72 + 32 = 104 deg farenheidt & thats way too cool. The right temp is around 180 deg [82 centigrade] If you are running a 180 /82 degree thermostat, & your accurate temp guage, the one that measures the temp of the coolant in the head, right near the thermostat, says it is substantially less, then you have an engine that we all want as the common problem is overheating, not overcooling.

Where is this temperature reading being taken from?

Same question as the Dodgeman. Where is the aftermarket gauge sensor located? Also, could the gauge be faulty? What does the factory dash gauge read?
Sounds to me like you've got an under reading gauge as I doubt you could even buy a thermostat in that temp. range.
Matty

Ok - sorry for the delay in getting back about this one.

I went out and bought myself a new thermostat - from a different place and fitted it... now the temperature sits on about 70-80 degrees (at which stage the thermo fan comes on and caps any further temperature rise). So it would seem that the problem is solved. I'm thinking that it was maybe a faulty couple of thermostats.

now another question - what's the bad effects of having the water temperature so low when running at speed? I know my previous 40 degrees was too low but I always thought a cooler engine was a good thing.

No worries. You'll get less efficient fuel economy due to the cold manifold. And less hp since the engine (should be) tuned for the regular temperature.

Motor oil in general is designed to work best at 200 F degrees, which means a 180 F thermostat. Colder temps mean more friction, etc. In general