Cool Running

[tim leech]

My xantia TD I bought through this forum is great, the engines sweet, it pulls like a train and starts on the button!

However even if I leave it idling it neves get above 70 degrees, the heater is quite warm if not red hot and all seems well, also she warms up well thought even after about 5 minutes.

Should I worry?

[SwissSPEC]

Sounds like the thermostat may need changing. Not sure about damage, however, it will be using more fuel as the cars brain may think it needs a bit more fuel as its running cold, just like when a car is 1st started up on a cold morning if that makes sense?

[chinkostu]

Thermo might be stuck open slightly, so the engine can get warm but the thermo isn't shut all the way.

Either that or it has a really low temp thermostat

[tim leech]

Fuel economy is great, it's doing late 40's even just locally.

Is the thermostat a big job?

It is very cold at the moment here!!

[Gibbo2286]

Don't worry about it, in my experience modern thermostats don't stick open, if they fail it's usually they stick shut due to the wax leaking out of the capsule. I think the stat setting is only 85 degrees on that car so a bit of tolerance in the temp shown at the gauge is probably all that you have.

[Xantidote]

I had to replace the thermostat on my TD a few years back, as the needle just wouldn't reach it's previous "normal" position on the gauge. Problem solved with new thermostat.

One way to check if the gauge is suspect, is to run the engine up to the point where the fans cut in, and see what temperature the gauge is then showing.

[tim leech]

Ok chaps, I will let it run and see if the fans cut in.

[old-un77]

My '03 Xsara pic runs on 3 segments, and I've never noticed the fan cutting in........

[ekjdm14]

Bit tricky to run till the fans cut in if it really is running cool, personally I'd just change the 'stat for what it's worth (after testing the new one in a pan of water to make sure it works, as even new ones can be dodgy on occasion) & do a coolant change while you have it empty. That way you're starting with a known quantity and have fresh antifreeze which is good in the weather we're having lately!

As far as diagnosis on-car, as I mentioned it's impossible/impractical to run till the fans kick in if it's running cold, what I'd rather do is start the engine from cold & keep my hand on the rad hose near the thermostat housing while the engine warms up. It should stay cold, cold, cold & then suddenly get warm as the 'stat opens if it's working OK. If the hose just gradually warms up in line with all the other coolant pipes you can lay a hand on then the 'stat has jammed at least partially open

[tim leech]

Left it running for half an hour today, the fans didn't cut in and the gauge stayed about 75 degrees! Hester is warm and the cars running well and returning 45mpg+!

I will leave it be!