Cold Start Issues

**Dino07** · 26-10-2010,12:59 AM

Recently purchased an 2001 (Y) Audi A3 TDI

Since I’ve had it, the cold start in the morning has been getting progressively worse. It's reached a stage today where it's almost as if the battery is about to die but suddenly fires into life. I let the glow plug light disappear before attempting to start.

On a side not, once I’ve run the car and its warm, if I switch it off and back to ignition, the glow plug light takes ages to disappear but start with no struggle.

After some read up, it seems it could be starter motor, glow plugs or a temp sensor. Before attempting anything, I just wanted to gauge a few opinions?

Many thanks

**NickPicks** · 26-10-2010,08:59 AM

To me, it sounds like the glow plugs need replacing, although I'm not an expert on Audi TDI engines, that's what fixed it on several other diesels my dad has owned.

**Crasher** · 26-10-2010,09:35 AM

More than likely you need a new coolant temperature sensor but have a fault code read done first. It is also possible that it needs new glow plugs as Nick says. What is the cars engine type code?

**Dino07** · 27-10-2010,02:05 PM

I gave the car a full service yesterday including plugs and although making a slight difference, it still struggles with the first start of the day.

I'm not 100% sure about engine type, how could i check?

**Crasher** · 27-10-2010,03:14 PM

Service book , log book, data sticker, cam cover.

**lennyboy** · 27-10-2010,04:56 PM

I'm sure it's glow plugs.Glow plugs are only used to start a diesel engine unlike spark plugs which work on every stroke

**Crasher** · 27-10-2010,05:34 PM

Glow plugs are run as part of the running strategy when cold until the ECU decides to turn them off.

**Dino07** · 01-11-2010,12:53 PM

The engine code is ASV.

I've been away for the weekend which has meant the car has been sitting there for 2 days. When i came to start it, it took around 10-15 of slow cranking before the engine finally started.

Glow plugs were changed during the service so i can definately rule them out i think.

Is the coolant sensor a difficult expensive replacement? Im considering replacing that before spending money for it to be put on a diagnostic if its a fairly common fault.

**Crasher** · 01-11-2010,01:39 PM

It is THE most common fault and easy to chnage, only do it when the engine is cold. It is in the water housing on the end of the head over the gearbox.