The purpose of the thermostat - after warmup - is to maintain a constant
temperature for best operation. An inoperative thermostat - stuck open - means
a slow warmup - not good for the engine, and improper operating tempterature,
also not good for the engine. Both conditions contribute to excessive wear on
parts.

You could be having problems with the blue temperature sensor that send to the
temp gage. If you are in a hot climate, and the gage shows cool, but you hear
your cooling fans cycle on and off....it is definitely the blue temp sensor.
Otherwise its the thermostat.

Luck,

John Rodgers
88GL driver

David Del Ben wrote:

> Hi all,
> Have an issue with my engine running cold. The temperature gauge pretty
> much stays o the edge of the white shaded area of the gauge.
> I'm pretty confident the gauge is reading accurate as we have just passed
> thru a winter here and it takes a while for the Heater to warm up and get
> decent hot air from the vents. Also, sometimes, stuck in traffic, the
> needle does sway more to the middle of the gauge (where it should be) and
> you can feel nice hot air from the vents.
>
> I very much suspect the thermostat is stuck open - but I've performed a
> 'band-aid fix' by substantially blocking of air to the radiator to try &
> get it to run a bit warmer.
>
> My question:
> I've been reading on the list about the lengths people go to to put oil
> temp gauges & head temp gauges and all sorts of tricks to keep an eye on
> the engine (head) temps. Seems to be a critical sort of thing.
> Hey - why don't I just leave the thermostat as it is and let the engine run
> a little cooler. Is that going to be better for the engine? As I said -
> we've just come out of winter - and I managed with the Heater as it is.
>
> Any thoughts - anyone.
>
> David Del Ben
> 85 1.9 Vanagon