Engine temp

dan_b

dan_b

A2OC Donor
I'm beginning to think I may have a problem with the engine temperatures. Ok I know it's winter, but...

The car never seems to reach an indicated 90 on the gauge. I can't actually remember when it last got there to be honest, thinking back I don't think it was even reading 90 in the summer. I know it's cold so it would be reasonable for it to take longer to reach full operating temperature, but even on a 2-hour motorway drive yesterday (outside temp 7degrees) at 80mph the temperature was stuck on the line before 90 (so I guess that's what, 75?).

Fuel economy is not great, but that could be the cold weather and winter diesel effect.

Suggestions? Faulty temp sender? Faulty gauge? Faulty thermostat? Or is it just because it's cold? Any easy way to check? What's easiest to replace first?
 
I had this problem and it was a faulty temp gauge.

I think im right in saying it should steadily climb and reach 90. Mine wasnt a big job, nor an expensive one to sort out.
 
My diesel always reaches 90 C, winter or summer.

Sounds like you need to plug it in to a vag-com to be sure of the fault.
 
This might sound like a stupid question, but is your aux heater on ECON?
If so, you'll never be able to get it to 90 in cold weather, even after several hours.
If not, after a few minutes with the engine running, touch the engine and the radiator. If the engine si not up to temp but the radiator is warm, then you have a faulty bypass valve stuck on open.
If this is not the case either, plug the old gal to a scanner and ask her about her health.

PS: sorry about all the "if...then" cases, but programming languages have a way to affect my written performance.:D
 
trex said:
This might sound like a stupid question, but is your aux heater on ECON?
If so, you'll never be able to get it to 90 in cold weather, even after several hours.
Click to expand...

Really? I've not noticed any difference. Maybe I've just not been driving in cold enough conditions? Coldest so far this year is -5C. I'm off to Scotland soon, where it's been -15C. I'll know more then I guess.
 
No such thing as a stupid question when you're trying to diagnose faults - sometimes it's the obvious stupid question that never gets asked that is the cause!

In answer - no, ECON is not on.
Thanks for the tip on checking the relative temps of the block and the rad - will do that next time we go for a decent run. Will also take my error code scanner outside and check for codes, although the last time I pulled fault codes when I had the misfire only one came up which was related to the faulty wiring loom, which was then cleared once the new loom went in...
 
If the gauge is not behaving erratically, I would put my money on the thermostat or, more likely, the cold weather. At this time of year my 1.2Tdi takes ages to get to 90°C, especially with the A/C on.

The sensor is not situated on the coolant outlet from the engine but on the inlet to the radiator (I think), so that may explain why it takes so long to warm up in this weather.

RAB
 
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This thread covers thermostat and temp sensor issues. I've changed both and would put money (but not a lot) on it being the sensor

Cheers Spike
 
Where is the sensor located and is there a way to check? Are they expensive to replace thermostat too?
 
Hmm, I don't get the wandering gauge symptoms, it just gets to the mark before 90 and never goes above.
 
dan_b said:
Hmm, I don't get the wandering gauge symptoms, it just gets to the mark before 90 and never goes above.
Click to expand...

I've experienced this too over the last couple of weeks. Sometimes it gets to 90, sometimes it hovers just above 80 and doesn't seem to go any higher. There's no pattern to it, so either the temp sender Spike mentioned is on it's way out or I'm beginning to think it's just the cold weather. Keeping an eye on it...

Jon
 
dan_b said:
Hmm, I don't get the wandering gauge symptoms, it just gets to the mark before 90 and never goes above.
Click to expand...

After an hours running, if the cabin heater is a lot colder than normal its more likely to be the thermostat stuck partially open. If the cab gets to normal temp then its probably a faulty temp sensor. Don't eliminate a sensor problem just because the temp gauge needle does not wander.
Wonder if its possible to remove the temp sensor, blank off the hole to prevent coolant loss then dangle the sensor in a container of boiling water. With the sensor connected and the ignition on, the temp gauge should read over 90C if the sensor is not faulty.

Cheers Spike
 
Cheers cabin heating works fine as far as I can tell. Ill change the sensor and see where we go from there...
 
Just some info on how to keep the engine temperature as high as possible in about -30 degrees celsius conditions. Turn on RECIRC and then lower the fan speed to 2 or 3 dots. This will turn off AUTO but the engine will stay warm. When the engine has reached 90 degrees you can now turn on AUTO and it starts to blow like crazy...then the engine temperature will drop and you repeat the process...:)

After a few "sessions" you will learn how to adjust the fan speed to keep the engine temp as high as possible while the cabin is still as comfortable as possible. This will take place at about -25 to -35 degrees celsius. Any colder than that, and the A2 will struggle to keep you and itself warm.
 
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Got my replacement temp sender in the post today from Stoke Audi. Will see about fitting it in the next few days.
 
Just got back from a -20 degree 45-55 mph ride and it's really hard for the car to stay at 90. A little downhill and the needle drops to 80 and coasting it for a mile will drop it to 70. Climate control set at 21 degrees, AUTO.
 
To be honest, I don't think it's made any difference, it still doesn't reach 90. I think it's my thermostat.
 
I would say so too. If nothing else, at least you know the sensor will be ok. What was the condition of the sensor when you pulled out the old one?
 
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