Xantia Thermostat - 15% better fuel economy

This is the Forum for all your Citroen Technical Questions, Problems or Advice.
reffro
Posts: 127
Joined: 01 Jul 2002, 15:24

Xantia Thermostat - 15% better fuel economy

Unread post by reffro »

More of a quick tale rather than a specific question. Over the holiday period I changed my car's thermostat. I have a 94 Xantia 2.0i 8v VSX auto, that prior to the change was running very cool.
We had a topic on hear a few weeks back dealing with subject, but I thought I would add my observations.
I have saved the cost of the new thermostat from the a Citroen dealer (£11) in my first 400 miles. Prior to the change the temp gauge would be showing about 61 degrees in normal open road running. To get any heat from the heater into the car it needed to be set pretty much at the max. Now with the new thermostat the car runs at 82 degrees, the heater works properly and fuel comsumption has been slashed.
Prior to the change I could expect 320-330 miles between fills. On my first tank after that, I hit 400 miles with ease. Admittedly that was including long motorway run, but I will check the fuel consumption at the end of this week on my normal commute and let you know the results.
But the basic advice even at this stage to anyone with a petrol Xantia that runs cool is, replace your car's thermostat. Its a 20 minute job that should save me £20-30 quid a month in fuel bills.
mbunting
Posts: 712
Joined: 21 Dec 2001, 15:19

Unread post by mbunting »

Interesting..
I have mine scheduled for replacement ( along with the coolant ) at the weekend.
I also have the rear Anti-Roll bar bolts to do..
Hoping for the use of a pit, should make it much easier !
Mat.
94 Xantia TDSX
reffro
Posts: 127
Joined: 01 Jul 2002, 15:24

Unread post by reffro »

I would suspect that the change of thermostat might not have as great as effect on a diesel engine as it has had with my Xantia. Just for the record I got the calculator out to see what the economy figure was for that 400+ mile tank.
It worked out at 31mpg, and that included plenty of 85mph cruising, plus the one excursion to 120mph when some upstart in an orange Saxo got a bit bolshie. For a 2.0 litre petrol auto that's a good return I thought.
mbunting
Posts: 712
Joined: 21 Dec 2001, 15:19

Unread post by mbunting »

Agreed.
I would think that the Petrol ECU would be monitoring the temperature, and adjusting the mixture / auto shift points accordingly. Therefore, because your engine never got warm, I would think it would be a high possibility that you were running on the choke a lot of the time.
I just want to get some heat back into the cabin. This morning was painful - 2 inches of snow over the car ( I live at the top of a 1:4 hill ). It took ages to warm up ( the dial never went above 65C ).
Changing it tomorrow..
Mat.