1.9TDI Engine Tempture

[Jdl93]

Hi All,

Ive got a 1.9 S Tdi Seat Ibiza, last night I changed the temperature sensor because it was all over the place and stuck on 71c in vag-com, and that issue seems to be fixed now.

However now, going along the motorway, it reads nearly 90c on the dashboard however on vag-com, i cant get it to go about 75c?

Is that normal temperature for a 1.9tdi?

Thanks in advance!

[andyiley]

Jdl93 said:

Hi All,

Ive got a 1.9 S Tdi Seat Ibiza, last night I changed the temperature sensor because it was all over the place and stuck on 71c in vag-com, and that issue seems to be fixed now.

However now, going along the motorway, it reads nearly 90c on the dashboard however on vag-com, i cant get it to go about 75c?

Is that normal temperature for a 1.9tdi?

Thanks in advance!

I don't know about your car specifically, but 90 sounds about what I would expect.

[ch427]

Thats about right, got 2 in the family that sit smack on 90 when warmed up and cruising.

[Mikey G]

VAG systems run a heavily 'damped' temperature gauge. A dash reading of 90 degrees can be anywhere between 80-100 degrees actual temperature of the engine.
75 on live data when running is a little low I recon, but not unusual. Could be worn thermostat opening too early.

[Steve_D]

Are you sure the car has only the one sensor?
Many have a sensor for the ECU and another for the gauge. In which case you don't know which one VAG com is looking at.

Steve

[littleredrooster]

Steve_D said:

Are you sure the car has only the one sensor?
Many have a sensor for the ECU and another for the gauge. In which case you don't know which one VAG com is looking at.

Steve

^ ^ This

ECU sensor is different to gauge sensor. As long as they both go up and down together, I wouldn't worry. 90 sounds right for the gauge temperature.

[Mikey G]

Actually, it depends on the year.
Early models had the 4 wire sensor, 2 for ecu and 2 for temp gauge.
Later models running multiplexed or canbus have a 2 wire sensor which the ecu then communicates the temperature to instruments via the network.

[Jdl93]

Thanks for your help chaps.

If its running 75c on vag-com? its surely running a little cold then.

Is the thermostat worth replacing?

[Mikey G]

Its not that cold, diesels are a pain to warm up and take an age which is why most now have pre heating systems in the water to help.
For the sake of it if its the original then may be worth a change, but don't worry too much about it.

[Jdl93]

Mikey G said:

Its not that cold, diesels are a pain to warm up and take an age which is why most now have pre heating systems in the water to help.
For the sake of it if its the original then may be worth a change, but don't worry too much about it.

I worry about cars all the time! Might be worth changing the thermostat then, I believe its the original.

Mpg is about 50ish, although id expect that to be nearer 55-60, which the other car gets(Which is a golf 1.9 tdi 110)

[Mojocvh]

Jdl93 said:

Thanks for your help chaps.

If its running 75c on vag-com? its surely running a little cold then.

Is the thermostat worth replacing?

You may be able to interrogate the ecu reading from the climate control panel Note "May"

I have a very similar issue with a 1.8T AJL at present, changed the twin sensor but still does the same, ie warms up to 90 then with a quick sprint to say 70+ temp goes back down to about 70C not too happy with the heat cycles it's putting the block through but changing the stat without a lift is a challenge to say the least...

[AJB]

Mojocvh said:

I have a very similar issue with a 1.8T AJL at present, changed the twin sensor but still does the same, ie warms up to 90 then with a quick sprint to say 70+ temp goes back down to about 70C not too happy with the heat cycles it's putting the block through but changing the stat without a lift is a challenge to say the least...

I wouldn't worry about heat cycles (although it's prob still worth changing the thermostat if you can face it, to get it running at the right temperature). The gauge lies, and reports exactly 90 as long as the temperature is "in range", which is maybe 75-100 or something. So, I'd think yours is running cold - eg maybe about 75 most of the time - but just in range and therefore saying 90. If it gets a few degrees colder (eg light throttle at speed) it drops out of the "lie because everything is OK" region, and reports the truth saying 70.

I doubt it's actually cycling all that much more than with a healthy 'stat - it's more likely just running cold all the time.