Not sure on the bleeding procedure on these tbh, could be air still trapped the heaters working ok i guess?
How much you putting in exactly?
Egg cup full or more?
How much you putting in exactly?
Egg cup full or more?
Yes the heaters seem to be working ok. And yes, I would say it's probably about an egg cup full. But I've done it three times now. 
Very interesting thread. Just took me half an hour to find this sender thing on my Cupra.... great these modern cars 
My problem seems to be the same. Intermittently the dash temperature guage just stopped working. A simple re-key of the ignition usually reset. However now this method is not even working. Watched the guage today and it went up then all of a sudden just dropped out.
I tried disconnecting the sender connector hoping that I could see the guage drop out on the car to prove this was at fault. However as it is now very intermittent this didn't work and all I succeeded in doing is getting the diagnostics light on the dash. DOH! I really should know better than to disconnect sensors.
So now I have two problems. I need to buy and fit a new sender and then reset the diagnostics light. Anyone in south Birmingham that knows anywhere or how to do this?
My problem seems to be the same. Intermittently the dash temperature guage just stopped working. A simple re-key of the ignition usually reset. However now this method is not even working. Watched the guage today and it went up then all of a sudden just dropped out.
I tried disconnecting the sender connector hoping that I could see the guage drop out on the car to prove this was at fault. However as it is now very intermittent this didn't work and all I succeeded in doing is getting the diagnostics light on the dash. DOH! I really should know better than to disconnect sensors.
So now I have two problems. I need to buy and fit a new sender and then reset the diagnostics light. Anyone in south Birmingham that knows anywhere or how to do this?
right i got ya, my gauge doesnt work and vagcom said it was coolant sensor so i changed the one held in by the c clip on the right hand side of the engine, i replaced still no joy. which sensor did u change i have a 1.8 20vt cupra 2001 as this is starting to annoy me lol
The VR5 and VR6 engines have a separate thermostat housing that contains the coolant temperature sender.
LC 180 defo does not have a sender in the stat housing... so any guage problems are either the CTS or the stat itself!
Just to confuse things, 5 days ago had an erractic needle changed the CTS (Coolant Temp Sender) green 4pin plug held in with a horseshoe clip. Didn't fix my fault.
Changed thermostat located front of the block by the water pump and also behind alternator and problem solved needle sits steady at 90 now.
What i want to know is;
1,Where the needle reads from.
2,Where the climate control code 51 engine coolant temp reads from.
Changed thermostat located front of the block by the water pump and also behind alternator and problem solved needle sits steady at 90 now.
What i want to know is;
1,Where the needle reads from.
2,Where the climate control code 51 engine coolant temp reads from.
I only ask as they read different sometimes upto 50 degress C but once Coolant is fully warmed up both stay steady at 90.
Surely that proves there are two different sensors does it not?
Surely that proves there are two different sensors does it not?
Cunners wrote
Just to confuse things, 5 days ago had an erractic needle changed the CTS (Coolant Temp Sender) green 4pin plug held in with a horseshoe clip. Didn't fix my fault.
Changed thermostat located front of the block by the water pump and also behind alternator and problem solved needle sits steady at 90 now.
From the sound of that, you had a dodgy thermostat.
What i want to know is;
1,Where the needle reads from.
The CTS
2,Where the climate control code 51 engine coolant temp reads from.
The ECU, which gets its reading from the CTS, but a different sensor: there are two contained in the package.
Just to confuse things, 5 days ago had an erractic needle changed the CTS (Coolant Temp Sender) green 4pin plug held in with a horseshoe clip. Didn't fix my fault.
Changed thermostat located front of the block by the water pump and also behind alternator and problem solved needle sits steady at 90 now.
From the sound of that, you had a dodgy thermostat.
What i want to know is;
1,Where the needle reads from.
The CTS
2,Where the climate control code 51 engine coolant temp reads from.
The ECU, which gets its reading from the CTS, but a different sensor: there are two contained in the package.
So if the reading does come from the same sensor albeit a different part of the sensor how can it get such varying readings?
To prove this:-
When u ve been on a run, so both the needle and climate control are reading around 90, turn off engine and leave for 15mins or so. Upon returning do not start engine but switch on. Your needle will still read near 90 but the climte control will be reading down around 30. Still without starting your engine turn your heaters on and slowly but surely the climate control figure will creep back up to 90.
This has to prove the readings are coming from different locations, i dont know for sure but that indicates that to me
To prove this:-
When u ve been on a run, so both the needle and climate control are reading around 90, turn off engine and leave for 15mins or so. Upon returning do not start engine but switch on. Your needle will still read near 90 but the climte control will be reading down around 30. Still without starting your engine turn your heaters on and slowly but surely the climate control figure will creep back up to 90.
This has to prove the readings are coming from different locations, i dont know for sure but that indicates that to me
well i have no gauge well its not working i replaced sensor and it is still not working so there must be something :S
Cunners wrote
So if the reading does come from the same sensor albeit a different part of the sensor how can it get such varying readings?
The CTS package, the green thing with an electrical plug at one end, contains two *completely* *separate* sensors. They are physically close to each other but not electrically connected at all, and act in different ways. If you look at the electrical plug you'll see four connectors, two for each of the sensors.
The gauge sender is a simple thermally sensitive resistor, working off the 12V instrument supply and feeding the gauge directly. It doesn't need to be precise, its main function is to warn you of gross changes in the coolant temperature.
The ECU sender is a more precisely specified device, working off the 5V ECU supply and giving the ECU precise detail of the engine's temperature, which it needs to work out fuelling.
My guess is that the dash gauge comes from an earlier age when a car might well not be fitted with an ECU, and it's cheaper for VAG to keep the old gauge and make a two-sensor CTS than it is to provide a digital-signal compatible gauge that can display the reading from the ECU system.
When u ve been on a run, so both the needle and climate control are reading around 90, turn off engine and leave for 15mins or so. Upon returning do not start engine but switch on. Your needle will still read near 90 but the climte control will be reading down around 30. Still without starting your engine turn your heaters on and slowly but surely the climate control figure will creep back up to 90.
That's an interesting experiment. I can only guess what's going on. As I said above, the Climatronic is getting a signal processed by the ECU and powered from a different electrical supply. I'm guessing that without the fans on, the Climatronic unit doesn't care what the coolant temperature is, but that is quite a stretch.
On the other hand, switching on the heater fans does nothing to change the condition of the coolant - nothing is moving the liquid around the pipes unless the engine is running to power the water pump. So your experiment proves that the ECU sensor reacts unreliably when the engine is not switched on - a condition in which it doesn't have to perform at all
This has to prove the readings are coming from different locations, i dont know for sure but that indicates that to me
There's nowhere else a coolant temperature reading *can* come from.
So if the reading does come from the same sensor albeit a different part of the sensor how can it get such varying readings?
The CTS package, the green thing with an electrical plug at one end, contains two *completely* *separate* sensors. They are physically close to each other but not electrically connected at all, and act in different ways. If you look at the electrical plug you'll see four connectors, two for each of the sensors.
The gauge sender is a simple thermally sensitive resistor, working off the 12V instrument supply and feeding the gauge directly. It doesn't need to be precise, its main function is to warn you of gross changes in the coolant temperature.
The ECU sender is a more precisely specified device, working off the 5V ECU supply and giving the ECU precise detail of the engine's temperature, which it needs to work out fuelling.
My guess is that the dash gauge comes from an earlier age when a car might well not be fitted with an ECU, and it's cheaper for VAG to keep the old gauge and make a two-sensor CTS than it is to provide a digital-signal compatible gauge that can display the reading from the ECU system.
When u ve been on a run, so both the needle and climate control are reading around 90, turn off engine and leave for 15mins or so. Upon returning do not start engine but switch on. Your needle will still read near 90 but the climte control will be reading down around 30. Still without starting your engine turn your heaters on and slowly but surely the climate control figure will creep back up to 90.
That's an interesting experiment. I can only guess what's going on. As I said above, the Climatronic is getting a signal processed by the ECU and powered from a different electrical supply. I'm guessing that without the fans on, the Climatronic unit doesn't care what the coolant temperature is, but that is quite a stretch.
On the other hand, switching on the heater fans does nothing to change the condition of the coolant - nothing is moving the liquid around the pipes unless the engine is running to power the water pump. So your experiment proves that the ECU sensor reacts unreliably when the engine is not switched on - a condition in which it doesn't have to perform at all
This has to prove the readings are coming from different locations, i dont know for sure but that indicates that to me
There's nowhere else a coolant temperature reading *can* come from.
PATRICKSBRIGGS
Guest
i have been having a cold running prob on my leon cupra sits on bottom most of the time turn heater of it rises aa bit , so i have fitted the green top water temp sensor , instantly cured prob now reads 90 as it should . the job took me 5 minutes at most very easy to do cost £19 inc vat at gsf parts worthing only lost quarter litre water /coolant as well result 
cost £19 inc vat at gsf parts worthing only lost quarter litre water /coolant as well result 
after reading many, many threads on the same subject I decided to take a chance and change my temp sender unit (4 pin on the coolant pipe to the right of the engine) as my coolant/engine temp gauge on my LC180 rises to 90 then randomly drops to 75 then up/down etc... 5 min job as stated by many, real easy if the engine is stone cold, lost no coolant at all.
Shame it didn't solve my problem tho!
Whats the next thing? thermostat in the coolant system?
Cheers,
Leigh.
Shame it didn't solve my problem tho!
Whats the next thing? thermostat in the coolant system?
Cheers,
Leigh.
For the info of all, yes it was the thermostat. The clues are a temp gauge that sits at 90 in traffic then drops to 75ish when you put load on the engine then back up when you slow and on and on etc....
Mine also seemed to heat up too quick on cold mornings and bring the climate control on earlier then when the engine temp drops the heat you get out the vents seems to also fall off.
£20 part + 2 hours labour. Didnt fancy changing it myself as its very near the alternator and requires quite alot of time!
Hope this helps someone,
Happy motoring!
Mine also seemed to heat up too quick on cold mornings and bring the climate control on earlier then when the engine temp drops the heat you get out the vents seems to also fall off.
£20 part + 2 hours labour. Didnt fancy changing it myself as its very near the alternator and requires quite alot of time!
Hope this helps someone,
Happy motoring!
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