Problem with Car

r0qi4162fux9kg

Wonder of anyone has come across this...

Word of warning - I know noting about cars.

Audi A3 2006

Every couple of days the ASR light comes on and the engine fans spins up to (by the sounds of it max). Really noisy.
If I stop, turn the engine off and get out - open the petrol cap - I hiss of air/ vapour releases and I hear a creaking sound (like metal expanding) from under the car. I'm assuming this is the tank.

If I restart the car the light stays of and the fans don't come on.

If I don't to this for a good few days eventually a yellow engine light comes on.

Have been driving the car regularly since last summer. This only started in the last month. Was bought from new by a close fanily member. Serviced last December.

Does anyone have any suggestions on where to bring it? Can't really afford a main dealer at the moment. It's always been serviced by one tho.

Thanks,
S

biko

"Petrol cap hiss" happens in many cars. Most often when run from full tank to low tank.
The decreasing level of petrol leaves a vacuum of sorts and when you open the cap air rushes in.
It could be connected to the engine light in that the pressure changes and if not released it'll affect the engine operation and throw a light.
A new fuel cap may or may not fix it, but it's the cheapest troubleshooting start.

ASR is anti-slip regulation. It's to do with traction, not with the engine.
I think you need the fault codes read.

valerossi

Bilko's dead on their when your car goes from full to empty you create negative pressure in the fuel tank so do try replace the cap with an original if possible.

sebastianlieken

Just wandering through this thread...

So, negative pressure in the fuel tank, does that mean the engine is running more lean as it cannot get enough petrol into the fuel mix? and hence overheating the engine, causeing the fan to go into full panic attack mode?

is it possible the ASR is throwing up a fault because the drivetrain is getting more power from the engine that the computer means to deliver (lean fuel mixture) hence putting more torque through the wheels causing (what the on board computer registers as) slippage?

or is my imagination running wild here? :pac:

Cheensbo

sebastianlieken wrote: »

Just wandering through this thread...

So, negative pressure in the fuel tank, does that mean the engine is running more lean as it cannot get enough petrol into the fuel mix? and hence overheating the engine, causeing the fan to go into full panic attack mode?

is it possible the ASR is throwing up a fault because the drivetrain is getting more power from the engine that the computer means to deliver (lean fuel mixture) hence putting more torque through the wheels causing (what the on board computer registers as) slippage?

or is my imagination running wild here? :pac:

The negative pressure would be - the fuel is pumped out, when something is removed from a space, something else (air) must replace it, if not, a vacuum is created, in this case, the fuel pump creates the vacuum, if the filler cap is sealed, air cannot enter to fill the void, hence the whoosh when you open it.

My guess is the fans always come on when the coolant temp requires them to, and most people only notice this when they feel there is an issue with their car - as they're looking for abnormalities...

the 2nd part, no, running lean would not deliver more power, and more power would not cause that, nice thought-train though, outside the box

My reckoning its either a sensor, or worn brake pads or something simple like that, a diagnostic check will show the cause anyway.

r0qi4162fux9kg

Thanks for all the replies.

Where can I get a diagnostic check done? Any idea on cost?

I will order a new fuel cap and see if this has any effect.

In terms of fuel. I filled the tank 3/4 full in or around the first week of April. Since then I've been always around the 1/4 full mark. Have been topping up with €20/30.

The fans are definitely running at a higher speed. You can hear the difference. But only when the ASR light is on.

Today for example.
Driving into the underground car park in work - window open - no ASR light - no noise.

Yesterday same process but ASR light was on. Car sounded like a jet coming into land.

Thanks again for the replies.

biko

Johan Nutritious Luck wrote: »

Where can I get a diagnostic check done? Any idea on cost?

About 50 give or take where you go.
Location?

r0qi4162fux9kg

biko wrote: »

About 50 give or take where you go.
Location?

Thanks for this.

I'm in Dublin City Centre.

S

biko

George Dalton can probably do you a good price in Bray. He's a member here so search him and send a PM.

r0qi4162fux9kg

Thanks a million!