Temperature doesn’t stay at 90c

[Victoria]

Hey, anyone knows what could be the issue with the temperature dropping or is it normal? Bought a6 2.0 diesel and it can’t seem to stay at 90c I changed thermostat it’s currently around -11 outside and it would warm up to 90c while driving then as soon as im in the city it drops to 80c and if i turn up the fans inside it drops even lower. I had previously a4 b8 2.0 and never had any issues with the temperature. I know the engine has to stay at 90c to operate properly and I’m worried about dpf filter not having a chance to regenerate because of the temperature. I only drove around 30km a day so the temperature inconsistent is bothering me and I’m not really getting any good answers from mechanics.

[Magnet]

Hello Victoria,

Welcome, and thanks for joining.

What brand of thermostat did you use as a replacement? 
Kind regards, 

Gareth. 

[JMKC82]

Hi Victoria,

Could it simply be that when you are going through the city that the engine is on idle or lower RPM more, therefore not generating heat.  At -11C, the engine and radiator temperature is going to drop quite quickly.

Anyone, correct me if i'm wrong, when you turn up the fan inside the car, the heat is being drawn from the cooling system (radiator) to heat the inside of the car, unless you have auxiliary heater.  Therefore, the engine coolant temperature is going to drop slightly quicker.

If you have stop/start, the engine isn't producing any heat when stopped at traffic, so temperature is going to fall quicker.

Was your A4 a petrol or diesel?  Did it have stop/start?  just trying to make sure we are comparing apples with apples.

Thanks, Joe

[Victoria]

Volmano, with opening temperature at 87c

A4 was diesel too, didnt have start/stop but that one get deactivated in cold weather automatically.

 

[Magnet]

Never heard of that make - China’s best?? 
Having had too many inefficient new-out -of-the-box aftermarket thermostats over the decades, I’ve long since resorted to paying the extra, and only buying main dealer ones. 
There’s something in my mind which points me to the possibility of two thermostats on some models, but I could well be wrong. 

[Victoria]

There isn’t a lot of options when buying car parts in Norway sadly, and none of the car parts are ever cheap. Just wondered if anyone else had this problem and found a solution. -12 is not even that cold here and I’m worried whats going to happen when its -20. I know that the car not reaching its operating temperature is a bad thing and I have noticed the fuel consumption seems high too compared to every other audi car I ever owned which is too probably connected to the low engine temperature. The second thermostat is a thing i think however wasn’t pointed out by mechanic and this is what bothers me, I’m not getting any real help here from professionals only speculations, though maybe someone on internet might know an answer 😅

[Magnet]

So you don’t have an option of buying a thermostat from a VAG dealer - ? 
Kind regards,

Gareth. 

[Victoria]

It’s a country that forces you to buy things that either originally comes from Norway or buy from companies that are Norwegian for high prices and if you still choose to buy from abroad you are going to pay double the price because of the taxes. I used to buy car parts from AutoDoc since its mostly good quality and low prices but a few years ago Norway decided that everyone will have to pay taxes on items from abroad so you can buy a car part for 200e and then you will pay 100e more when it arrives… so ordering outside Norway is out of question😂

[Magnet]

Thanks Victoria, but it would be good to have an answer to:- 

Can you go into an Audi or VAG dealer and buy the part from them? 

[Victoria]

I just said ordering car parts outside the country is not possible.🙂 our workshops order parts from dealers inside the country the same parts that we can buy online too. All parts are made to be used in cold weather since it gets up to -30 here in winter so we don’t have parts that are in bad quality unless you buy from China urself. Audi or VAG is not possible unless you have a brand new car and its the Audi dealer that repairs it. I highly doubt that its the part that is faulty and wondered if anyone knows what else could be wrong. The inside warms up nicely so I don’t freeze while driving but the low oil temperature is not reassuring.

[Magnet]

So to box this up:-

You may have an Audi dealer within travelling distance -? 
If you go to that dealer and ask them to supply/order a thermostat they won’t sell it to you -? 

[Magnet]

Hello Victoria,

Wondered how things are going with this, and whether you may be able to assist with the answers to the last couple of questions.

I hope I’m not coming over as being confrontational, but I, and I guess other forum members, are completely ignorant of how the motor repair business actually works in Norway, so it would be great if you could fill in some of the interesting details for us.

Many thanks and kind regards,

Gareth.

[Vidas]

On 12/7/2023 at 11:54 AM, Victoria said:

Hey, anyone knows what could be the issue with the temperature dropping or is it normal? Bought a6 2.0 diesel and it can’t seem to stay at 90c I changed thermostat it’s currently around -11 outside and it would warm up to 90c while driving then as soon as im in the city it drops to 80c and if i turn up the fans inside it drops even lower. I had previously a4 b8 2.0 and never had any issues with the temperature. I know the engine has to stay at 90c to operate properly and I’m worried about dpf filter not having a chance to regenerate because of the temperature. I only drove around 30km a day so the temperature inconsistent is bothering me and I’m not really getting any good answers from mechanics.

hi guys, did anyone sorted it out? I have the same issue with the temp dropping down, I’ve changed two thermostats (aftermarket) and coolant temp sensor. Still have the same issue 😕 if someone sorted it out pls share your information maybe it will help to me.

[Victoria]

Still haven’t sorted this out. I have programmed out DPF filter since that one was bothering me for a while. So the temperature problem has gotten even worse. I have also changed the second thermostat and got informed by someone that there is possibly even a third one. Still unsure about that. However I can’t see the point of buying original thermostat, since the one I have installed is supposed to open at 80 degrees and the temperature barely ever reaches it. Had a cold week here, had to drive to work while the outside temperature was -20c. Car temperature didn’t go over 60c so I was freezing the whole way to work. This is probably critical for the engine too. 

[Victoria]

Got advice to buy the plastic cover that is right under the engine since mine is gone. But I still don’t see how this would help the car to reach 90c, maybe 70c but not up to 90c. The car only reaches 90c on long trips on highway. When I drive at least 100km/h but as soon as I slow down it drops again no matter if it’s -20 -5 or +5 outside. I have bought the car three months ago so I don’t know if it’s been like this for a while or something recent. I have owned a4 b8 2.0tdi, a6 c6 2.0tdi, audi a4 b6 1.9tdi, vw sharan/caravelle, audi q5 2.0. None of these had any problem to reach the operating temperature no matter the outside temperature. No mechanic has any idea but different small things that I could change and see if it helps. 

[Victoria]

I will of course buy the cover for other reasons as well. Not sure it will help the car to reach the operating temperature but it will definitely help to prevent any objects from damaging the engine from underneath. I have however placed a cardboard over the radiator behind the grill which didn’t help much. 

[JamesQ]

On 2/10/2024 at 10:49 PM, Victoria said:

I will of course buy the cover for other reasons as well. Not sure it will help the car to reach the operating temperature but it will definitely help to prevent any objects from damaging the engine from underneath. I have however placed a cardboard over the radiator behind the grill which didn’t help much. 

Hi Victoria, I was just wondering if buying the tray has fixed your issue? I am having the same issue. Mine is running between 70-75 degrees and I’ve took the same measures as you have with no joy. Desperate for any new advice at this stage. 
Thanks,

James 

[Gheorghe]

On 2/10/2024 at 8:53 PM, Vidas said:

hi guys, did anyone sorted it out? I have the same issue with the temp dropping down, I’ve changed two thermostats (aftermarket) and coolant temp sensor. Still have the same issue 😕 if someone sorted it out pls share your information maybe it will help to me.

Hi, i have the same issue, i change thermostat 3 times, different brands but new,  and another 2 times with used one. Same issues...

[DaveOL89]

Hi,

 

have the waterpump and timing belt been changed? What’s the mileage? VAG group are well known for the water pumps failing before the belts and pumps can fail in different ways.

 

failing that I’d recommend getting a live data test done on the injectors, both at idle and during drive and see if any are running lean or rich. Especially considering the cold temps of the diesel in your climate.
 

if one injector is overfueling or underfueling this is likely to cause the engine not to get to temperature.given it’s an older Audi I can assume it has some mileage on it.

[Gheorghe]

Hi, timing belt and water pump done at 100k , now is 152k 

I will check injectors this week. Thank you

[Magnet]

Am I missing something here, but what do injectors have to do with maintaining coolant temp? 
Kind regards,

Gareth. 

[Stevey Y]

16 minutes ago, Magnet said:

Am I missing something here, but what do injectors have to do with maintaining coolant temp? 
Kind regards,

Gareth. 

HI Gareth, if the live data shows the injectors are running rich that means the engine temp will be cooler due to bad combustion, lean combustion will cause rapid warming internally therefore commanding the pump thermostat remain fully open despite the low ambient temp, I think the original posters problem was the oil fired auxiliary heater which was always a problem on cars sold in Scandinavia.

Steve.