A3 8V No Heat Diagnosis

[Chris777]

Thanks Matt, appreciate your help

It's the little 1.4 TFSI petrol. Few more pics of mine if can point out where you mean.

That last pic is looking up from under the middle of the bumper, is that the auxillary water pump? Could that be anything to do with? 

Where about is the stat located in all that jumble sorry I havnt got a clue.

It's almost like when revving getting the flow but when idling not sufficient. I thought the top pipe was coming from the stat then round the radiator and cooled out the bottom? I've got back to front have i?

Just coz top pipe gets toasty while bottom does get slightly warm (i mean the bottom pipe on near side with the temp sensor on the corner) other side / drivers side bottom pipe gets warm

[Sid2020]

The thermostat is inside the housing so can not be seen from the outside, it controls the flow out of this port on the block 

[Sid2020]

Secondary water pumps on many manufacturers are solely used to keep coolant circulating when the engine is shut off to prevent localized boiling around turbos and similar components, it seems that Audi have also been using them to aid the mechanical water pump while the engine is running after abit of research. I never considered this and is possibly a big oversight on my part. First thing is make sure you definitely have one fitted, then check the fuse is okay and if it’s accessible try to place a finger on it and try to feel a huming from it to see if it’s spinning

[Chris777]

Thanks Matt

Firstly mate, really appreciate you sticking with me your support is great.

When I first got it and run a Carly it came up (pic attached)

Code said on google 'auxillary pump dry running' as wasn't open circuit and all coolant had been dumped in the crash I just thought stored and didn't come back after codes cleared. 

Looking back at the log it seems like 2 showed. Couple videos show 2 pumps

1.Heater support pump

2.Coolant pump for charge pressure cooler

but think that's on a diesel (one at front like on the last pic of mine above) thought maybe the front was charge pressure one and I've not looked properly yet if one behind the sump as can't get skid tray all way off those t45s are a nightmare. But will look again tomorrow. 

I'm thinking that front one is low down and close to impact point would it affect the pressure of the whole system? I also dismissed initially as seemed to suggest that was only when parked to keep heaters warm but circling back to as heat now on 2k revs but cold idle and if also controls pressure/ flow could it be....

[Sid2020]

13 minutes ago, Chris777 said:

Thanks Matt

Firstly mate, really appreciate you sticking with me your support is great.

When I first got it and run a Carly it came up (pic attached)

Code said on google 'auxillary pump dry running' as wasn't open circuit and all coolant had been dumped in the crash I just thought stored and didn't come back after codes cleared. 

Looking back at the log it seems like 2 showed. Couple videos show 2 pumps

1.Heater support pump

2.Coolant pump for charge pressure cooler

but think that's on a diesel (one at front like on the last pic of mine above) thought maybe the front was charge pressure one and I've not looked properly yet if one behind the sump as can't get skid tray all way off those t45s are a nightmare. But will look again tomorrow. 

I'm thinking that front one is low down and close to impact point would it affect the pressure of the whole system? I also dismissed initially as seemed to suggest that was only when parked to keep heaters warm but circling back to as heat now on 2k revs but cold idle and if also controls pressure/ flow could it be....

If the pump Has run dry for any extended length of time it’s possible It’s over heated and seized/burnt out . It being seized would not cause an issue with the system holding coolant or pressure but would obviously lack that extra push the main pump can’t  supply. A lot of cars are going over to coolant charge coolers now and main benefit is that they dont need to be in the airflow to work so can be mounted anywhere so  very possible You have one on your engine

[Sid2020]

If this is the same as yours it’s built into the inlet manifold

[Chris777]

Seems similar . Couple more pics of mine, will have try and get a part number off it.

Anyway of testing if is faulty ?

Error didn't come back after adding coolant