UK-POLOS.NET - THE VW Polo Forum

My 2003 1.4 polo 9n seems to be running cold I don't know If this is a major issue or can be solved easily I have just noticed the temp gauge hardly moves even after a long journey it doesn't sit at a normal temperature.
I also think its running a very rich mixture.

Could be a couple of things

Faulty thermostat

OR

Fault temperature sender

Id look to replace them and that should clear your problem

Would it record a fault code?

Faulty sender would yes

One thing I would add, if the temperature sensor is only slightly faulty, then maybe there would not be any fault codes getting logged yet. Is the engine coolant (pipes etc) feel like its getting hot enough?

I'd change them both for what they cost.

The rich mixture bit points at a sender rather than the thermostat though. On a run, I'd expect a petrol to warm up to operating temperature even if the thermostat's stuck open.

Wiring to the plug to the temp sender can fail on these too. (ours did, then the sender failed a year or 2 later!)

Do your mean sensor when you say sender? Or is the the fuel sender your talking about?

Sender/sensor are the same in this instance

Were talking about the temp sender

Okay thanks ill try changing the temp senser and see if that works it's went before about 2 years ago. So I know where it is.

Be sure to use a genuine vw replacement. Copy parts often fail especially temperature sensors.