Coolant temp gauge problems on A4 (B6) TDI

[sherbet31]

HI,

I am hoping someone out there can give me some advise on a problem i am having with my 2003 1.9 TDI 130 A4.

The coolant temperature showing on the gauge was only going to just above 70 degrees when i was on the motorway. I replaced the thermostat and the coolant temp sensor but there is still a problem.
The coolant temp will now get to 90 degrees but it sems to take a while and if i stop for traffic lights or traffic the gauge starts to drop towards 70 degrees again.
Tonight i got the temp upto 90 degrees and then left the car idling for approx 5 minutes and the temperature dropped down to 70 degrees. If i turn the car off for about 10 minutes or so the temperature again has dropped to around 70.
Is it possible that the viscous fan could be causing this?
I have checked the fan after 15 minutes driving and it seemed to spin freely with only a slight resistance and when the engine is cold the resistance goes.

Please Help!!!

Regards
Sherbet

 

[marktdisport]

it seems we all have the same issue with the B6 130hp,

 

[stu_m]

Turn your heating off and see what happens

It should warm up and hold temp

Your heating is acting like a radiator in this cold weather

 

[quattro tony]

Ive had an erratic temp gauge with my previous a4 1.9 tdi 130, It would rarely get to 90 degrees only when going long distance on motorways, most of the time it would sit around 70, 80 ish, temp sensor had been done , slightly improved, mpg still good so just left it.

 

[stu_m]

Once mine gets to 90 it will sit there all day long

Unless I have the heating off and then turn it on when the gauge gets to 90 it will drop to 70 ish then come back up slowly in hot weather it just gets to 90 in no time at all

 

[yendall24]

HI,

I am hoping someone out there can give me some advise on a problem i am having with my 2003 1.9 TDI 130 A4.

The coolant temperature showing on the gauge was only going to just above 70 degrees when i was on the motorway. I replaced the thermostat and the coolant temp sensor but there is still a problem.
The coolant temp will now get to 90 degrees but it sems to take a while and if i stop for traffic lights or traffic the gauge starts to drop towards 70 degrees again.
Tonight i got the temp upto 90 degrees and then left the car idling for approx 5 minutes and the temperature dropped down to 70 degrees. If i turn the car off for about 10 minutes or so the temperature again has dropped to around 70.
Is it possible that the viscous fan could be causing this?
I have checked the fan after 15 minutes driving and it seemed to spin freely with only a slight resistance and when the engine is cold the resistance goes.

Please Help!!!

Regards
Sherbet

i have the same engine as you and it is normal for a diesel to do this in very cold weather they are a lot more thermally eficient than petrol so therefore produce less heat .one more thing your car does not have a viscous fan you will have electric fans

 

[stuhow3361]

my temp gauge works occasionally but most of the time it reads zero,what needs changing and approx how much?

 

[pauldazzle]

my temp gauge works occasionally but most of the time it reads zero,what needs changing and approx how much?

Coolant temp sensor 1st, & if that doesn't improve things change the thermostat.

 

[stuhow3361]

where's the sensor located on the 1.9tdi?

 

[pauldazzle]

It's a bit of pain to get at as it's tucked away at the rear of the engine. I found the easiest way to get at it was to remove the large boost pipe off that runs around the rear of the engine.

 

[jay786]

Turn your heating off and see what happens

It should warm up and hold temp

Your heating is acting like a radiator in this cold weather

Same Problem .. if the heatings on it goes down to 70 Degrees .. is that normal? ... is that supposed to happen?
How do i fix this .. air in the cooling system?

 

[pauldazzle]

Same Problem .. if the heatings on it goes down to 70 Degrees .. is that normal? ... is that supposed to happen?
How do i fix this .. air in the cooling system?

Sounds like a thermostat problem not a CTS fault.

 

[jay786]

i just changed the thermostat today

 

[pauldazzle]

You probably have an air lock.
Take the header tank cap off, put the AC on hot, start the engine & hold the rpm's up to at least 2500 until temp gets up & hold it there for a few minutes. If you have an extra pair of hands available squeezing the top rad hose helps while doing this. Top up the header tank if needed, & leave the engine to cool down, then check coolant level again.

 

[pink.teg]

Just a quick Q
my 1.9tdi Quattro 2003 has as a viscous fan .

 

[marktdisport]

Just a quick Q
my 1.9tdi Quattro 2003 has as a viscous fan .

correct