Cupra temperature problem, please help....

[Gazaho]

Hi all,

My temperature gauge doesn't seem to be working properly. I'd start the car up and drive as normal, id see the temp rise up to 90 sometimes, sometimes in between, in traffic it climbs to 90 no problems. I go to pull off and drive it a a bit and notice the decrease on Temp Gauge, sometimes falls almost all the way to 60...

I have changed the green Temp Sensor already, problem persisted so I assumed it was the thermostat, got that changed and problem still remains and changed the temp sensor again and still no luck! Do I get the stat changed once more as that may be faulty?! It's doing my head in!

I went into the climate control menu to the CTS temp and it does show 90 after like driving a bit even though the temp gauge slowly creeps up...

Vagcom block 001 shows my the temp going up to 93/4 and goes back to 90...
Vagcom error says
17704 error in mapped cooling system check temp sensor or stat

Any help is much appreciated...

 

[Stuart09]

Airlock.

mk1 Leon cupra 1.8T 20v.

 

[tanto]

common fault on vag cars temp sensor and thermostat can be bought from euro car parts cheaply

 

[andycupra]

or water pump....

 

[Alexis27]

I'd get a genuine coolant temperature sensor. The non-VW versions have always caused me problems in the past

 

[mty12345]

By the way you describe the gauge moving, my money is firmly on the thermostat mate.

If it was the water pump it would overheat and if it was the temp sensor, you tend to get no reading, or the gauge reads 120C.

The temp on the climate control isnt the real temp. It's the 'back-up model' that the ECU uses in case the temp sensor fails. It slowly rises to 90C, based on time, and just stays dead on 90C after that. The real temp moves around a lot more when viewed on obd2 or vcds

 

[Gazaho]

So frustrating as I had it replaced not long ago...
Here's another thing, I start the car up, heating full blast on highest temp, the climate control climbed up to 90 within minutes.

Later on in the day, after not using the car for quite a few hours, I'll start her up and the temp on the climate control stays on 30 for ages...

Does that seem right at all? Or something to do with an airlock? Or I should just get the stat changed?

 

[mty12345]

1.8t does't usually suffer from airlocks in my experience. i would change the stat again mate.

 

[Stuart09]

Not sure how they cope if the heater was left off when bleeding the system. Are you getting full heat from the heater.

mk1 Leon cupra 1.8T 20v.

 

[mty12345]

Note how it says the thermostat should be fitted, with the 'brace' bit almost vertical. I've have never seen a reason why, but maybe it makes a difference in some way??

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[sockpuppet]

It doesn't show it in the diagram, but there is two lugs inside the housing that hold the thermostat in position. These either bend out of shape or break off when the housing is pulled away from the engine as the thermostat stays stuck to the engine instead of coming out with the housing. So it's possible that the stat is in the wrong position or could just be a faulty stat.

 

[mty12345]

It doesn't show it in the diagram, but there is two lugs inside the housing that hold the thermostat in position. These either bend out of shape or break off when the housing is pulled away from the engine as the thermostat stays stuck to the engine instead of coming out with the housing. So it's possible that the stat is in the wrong position or could just be a faulty stat.

Ah right, i never realised that

To the OP, that could well be the problem then. If the thermostat isn't being held tightly to the engine by those lugs that sockpuppet mentions, then that could allow water to circulate when it shouldn't be, i.e when the thermostat is meant to be closed.

Part numbers if you need a new housing.... http://seat.7zap.com/en/e/leon+leon+4/le/2003-268/1/121-121010/

 

[icestorm81]

It will be the thermostat, had 2 fitted last year, 2nd one no problems as of yet.