Attached are 3 pictures of the thermostat that i replaced in Alfenia today.
For fear of repeating myself, from stone cold start the thermostat would open at 70 deg C, as seen on the central gauge of my car. When the car was in normal traffic/driving the temp gauge would register < 60 deg C, only ever rising to 90 when in a traffic queue or when idling for long periods.
As far as I know *most* car's engines need to operate at approx 85 deg C, my car was operating at 25 deg C less. To me that implied an inefficent, cold engine & I suspect excessive fuel consumption
Previous to replacing this thermostat Alfen0ia was doing from 26 to 29 mpg .... therefore i decided to replace it.
The 1st picture shows the thermostat in its housing. Marked as "Hot Water from Engine" is the compartment that houses the thermostat & the temperature sensor for the ECU & console temp gauge. Until the thermostat opens, should open at 88 deg C, very little water *should* get thro to the area marked "Hot Water to Rad". In my case the thermostat/wax was *aged*. The unit was opening early at 70 deg C.
The 2nd picture shows the parts of the thermostat, when taken out of the housing... believe me removing the thermostat was NOT an easy task.... nearly lost a few knuckles
On the right is a *piston*, in the center is *the brains* of the thermostat & to the left is the spring/clamp that keeps the themostat closed until the water surrounding it reaches *88 deg C*. If you look closely you can see "88" stamped on teh edge of the brass clyinder , under the B & W...sorry for writing there
The 3rd picture shows the brass cylinder cut open to reveal *the brains*.
How does it work:
Internally there is a wax type substance that expands when hot. Between the piston & the wax is a fairly solid rubber that is pushed outwards when the wax expands due to the heat absorded by the brass cylinder. The movement of the rubber pushes the piston that in turn pushes in the oppposite direction on the spring therefore opening the thermostat. Once open the water [ H2O ] flows thro to the rad, where it is cooled. When the car is operating *normally* the thermostat opens & closes on a regular basis, depending on water temp in the "Hot Water from Engine" compartment.
New thermostat in Ireland, €49
Coolant: 1 gallon €10
Hose clips: various sizes, bought seperately, €3
Total time: 1 hour ..... free
BTW: Paul i didn't look for that valve, thanks for the tip
I'll have a look for it tomorrow & double check her for air.