[storme'd]

Guys, need some advise. My current drive is an Audi A8L quattro 3.0. Have been having quite an issue free experience with the car, however post getting it serviced from Halfords last week, I have seen the coolant temperature gauge oscillating between the middle and quarter position. It used to be fixed at the mid spot earlier but now the needle keeps moving. Thankfully it's not going beyond the half level so have not faced any issues.

1. Can this be due to something that happened during servicing?

2. What could be the culprit?

3. If it is the coolant temperature sensor, can I do a diy after buying it off Amazon?

Any advise will be helpful.

Thanks

[Maverick5490]

Does the temperature gauge fluctuate right from start up or once the engine is in operating temperature? Most likely its the sensor that may have failed causing the erratic display.

[ajmat]

Originally Posted by storme'd

Have been having quite an issue free experience with the car, however post getting it serviced from Halfords last week, I have seen the coolant temperature gauge oscillating between the middle and quarter position. It used to be fixed at the mid spot earlier but now the needle keeps moving. Thankfully it's not going beyond the half level so have not faced any issues.

1. Can this be due to something that happened during servicing?

2. What could be the culprit?

3. If it is the coolant temperature sensor, can I do a diy after buying it off Amazon?

Any advise will be helpful.

Thanks

First - Halfords may be best routine services of popular cars as opposed to a sophisticated Audi.

It could be a faulty temp sensor. Are you getting any error messages, fuel consumption issues? Some of the early 2000 VAG cars had defective sensors. My Skoda RS has this issue. For £15, I got a new sensor posted to me. Replaced it and it was sweet as a nut. This sits at the bottom of the block. Considering your v8, you could get lost!

[storme'd]

Originally Posted by ajmat

First - Halfords may be best routine services of popular cars as opposed to a sophisticated Audi.

It could be a faulty temp sensor. Are you getting any error messages, fuel consumption issues? Some of the early 2000 VAG cars had defective sensors. My Skoda RS has this issue. For £15, I got a new sensor posted to me. Replaced it and it was sweet as a nut. This sits at the bottom of the block. Considering your v8, you could get lost!

Thanks Ajmat. Yes, Halfords is great as my previous experience with Audi service wasn't that good. However with the current staff shortages in the UK across, I have seen even their standards go down. My car was returned to me with grease stains on seats and loads of other issues.

No I am not getting any error messages. Yes, I have noticed higher fuel consumption ever since this happened. Do you think these could be related? Also, ordering the part isn't a problem, but I am sure I will get lost and won't be able to do it. Do you reckon Halfords is a good bet for this?

Originally Posted by Maverick5490

Does the temperature gauge fluctuate right from start up or once the engine is in operating temperature? Most likely its the sensor that may have failed causing the erratic display.

It fluctuates after the engine has reached operating temperature. I too guess it may be the sensor. I have also noticed the fuel gauge falling faster than it used to earlier and higher fuel consumption.

[storme'd]

Just an update - I bought an obd scanner which didn't throw out any error codes. Funnily, enough the Temperature gauge is working fine now and resting comfortably at the halfway mark. Fuel consumption also seems to be back to normal. Thinking back, when this happened, I had filled up fuel from supermarkets twice (which I normally avoid) but am back to getting it from BP or shell. Guess adulterated fuel maybe the culprit here.

[v1p3r]

Good to see the issue's resolved itself but mate, Halfrauds, seriously? Not useful for much more than bulb changes.

Find a decent independent, they're quite easy to come across in the UK. Stick to an Audi/VAG specialist - also useful when you want to sell the car because they'll have buyers and they can vouch for the history.

Originally Posted by storme'd

Thinking back, when this happened, I had filled up fuel from supermarkets twice (which I normally avoid) but am back to getting it from BP or shell. Guess adulterated fuel maybe the culprit here.

Fun fact - supermarket fuel and name-brand fuel comes from the same refineries. Shell / Esso / BP just have additives added. In fact, for certain classes in motorsport, I remember specifically buying Tesco Momentum 99 because it was cheaper than Shell Optimax and slightly better performance as well.


Also, temperature and fuel are unrelated in the scenario you've mentioned.

[storme'd]

Originally Posted by v1p3r

Good to see the issue's resolved itself but mate, Halfrauds, seriously? Not useful for much more than bulb changes.


Find a decent independent, they're quite easy to come across in the UK. Stick to an Audi/VAG specialist - also useful when you want to sell the car because they'll have buyers and they can vouch for the history.

Fun fact - supermarket fuel and name-brand fuel comes from the same refineries. Shell / Esso / BP just have additives added. In fact, for certain classes in motorsport, I remember specifically buying Tesco Momentum 99 because it was cheaper than Shell Optimax and slightly better performance as well.


Also, temperature and fuel are unrelated in the scenario you've mentioned.

Funnily, when my headlight bulb died, they refused to change it stating the jolt could kill them and they aren't allowed to change D2S bulbs. I had to go to an independent who took over an hour to open the wheels and then change the bulb. I am looking for a good independent now. My friend owns several service stations in Hampshire and he specifically asked me not to go to supermarkets for fuel. But due to the fact that we aren't getting fuel easily have to get from where available.

[ajmat]

Originally Posted by v1p3r

Also, temperature and fuel are unrelated in the scenario you've mentioned.

I had a consistent issue with my vRS in that it suddenly ran rich and set off the EPC light which then interfered with the throttle body tripping off the Engine light. It took me a long timed figured it out that it was a 13 quid temperature transducer at fault.

It sent "cold" signals to the ECU which triggered rich mixture which messed up the EPC parameters which confused the throttle body. Ordered one in the post, changed it while engine was cool and it ran so sweetly alas - I had committed on a sale at that point.

[Maverick5490]

Originally Posted by storme'd

Funnily, when my headlight bulb died, they refused to change it stating the jolt could kill them and they aren't allowed to change D2S bulbs.

LOL! Here in India our mechanics will be willing to dismantle the complete engine without any knowledge! What's the story with Halfrauds? or is it the fact that the name itself has 'Frauds' in it!

[ajmat]

Originally Posted by Maverick5490

LOL! Here in India our mechanics will be willing to dismantle the complete engine without any knowledge! What's the story with Halfrauds? or is it the fact that the name itself has 'Frauds' in it!

Halfords are mainly a retailer of car parts, accessories and bicycles. They also service cars. Its ok for an oil change, bulb change, filter change but their capability runs out beyond that.

Most of the mechanics are trained but not for specific manufacturers.They could handle ordinary cars but not sophisticated machinery. A lot of the mechanics are trainees or apprentices

Halfraud? They do MOT testing and they will find stuff that is wrong which might not be and needs to be repaired on the spot or driven home immediately as they enter on the system that the car is unfit.

In an analogue world, my Peugeot failed on 4 points. I took it back as the MOT was still valid (not expired )in those days and sent it to the dealer. Only only point was valid. Corrosion on the brake pipes.

[v1p3r]

Originally Posted by ajmat

I had a consistent issue with my vRS in that it suddenly ran rich and set off the EPC light which then interfered with the throttle body tripping off the Engine light. It took me a long timed figured it out that it was a 13 quid temperature transducer at fault.

It sent "cold" signals to the ECU which triggered rich mixture which messed up the EPC parameters which confused the throttle body. Ordered one in the post, changed it while engine was cool and it ran so sweetly alas - I had committed on a sale at that point.

I had a similar issue when I tuned mine, in that the throttle had a mind of its own. The electronic throttle would shut down when it sensed overboost since I ran a standalone in parallel, instead of a remap. Solution was to a Rs 0.50 resistor put into the MAP sensor next to the intercooler - the 1.8T uses a MAF and a MAP. Would merrily do 30 psi all day after that.

My point was the an oscillating temperature gauge is very likely unrelated to anything except a temperature sensor, and definitely not to fuel. Temp tends to work on a standalone circuit where it sends output to various other systems, but does not accept input from many. An oscillating gauge (once warmed) is strange and most likely to be an instrumentation or sensor gremlin within that system, or a massive electrical fault.

[storme'd]

Guys

My Audi A8 is giving me error no P0471. Sometimes the dpf error comes and sometimes the glow plus sign starts blinking. When this happens there is loss of power. I have tried driving on D3 in manual at rpm of 4k for over 20 miles but still doesn’t work. Can someone suggest something.

I am based in the uk.

Thanks

[Jeroen]

Originally Posted by storme'd

My Audi A8 is giving me error no P0471.

That is an transmission problem! You need to have it investigated properly.
Have a look:

https://www.700r4transmissionhq.com/p0741-audi-a4/

Good luck
Jeroen

[storme'd]

Thanks for this Jeroen. The error you are talking about is different from what I am getting. I am getting error P0471 which says “exhaust pressure sensor A circuit range / performance” on my obd. The link you sent is P0741.

I just need to know if there is any way to fix this. It related to the diesel particulate filter or sensor.

Originally Posted by Jeroen

That is an transmission problem! You need to have it investigated properly.
Have a look:

https://www.700r4transmissionhq.com/p0741-audi-a4/

Good luck
Jeroen

[Jeroen]

Originally Posted by storme'd

Thanks for this Jeroen. The error you are talking about is different from what I am getting. I am getting error P0471 which says “exhaust pressure sensor A circuit range / performance” on my obd. The link you sent is P0741.

I just need to know if there is any way to fix this. It related to the diesel particulate filter or sensor.

Sorry, my bad!
Here you go, plenty to check

https://scanneranswers.com/ob2-error-code-p0471-wrong/

Good luck
Jeroen