After-Run Coolant Pump

[Pete_RS2]

I had a flat battery this week & I think I've found the culprit - my after-run coolant pump is running all the time. Any ideas what could be wrong ?

[Mikes2]

Either a fault with the afterrun sensor, the controller or a wiring fault

The sensor should also trigger the rad fan into life on speed 1.

Controller looks like this:

http://www.s2-audi.co.uk/tech_articles/electrical/relay_pos_14.htm

I had a problem on my old S2 where the rad fan ran all the time. it was a bad connection on the resistor pack down by the washer bottle

[iain1067]

Had the same thing (rad fan actually) on my S4 turned out to be the timer realy, not sure if the S2 has one of these, but it's a common problem on the S4.

[Ski]

should the after run pump / rad run at all when the engine is switched off?

[iain1067]

yes that's the idea that it pumps coolant round to prevent the turbo cooking itself.

[Pete_RS2]

I don't suppose anybody's got a controller/relay I could try ?

[iain1067]

On the S4 you can test that both the pump and fan run at the same time by pulling off the connectors on a sensor screwed into a water manifold (for want of a better description) which sits underneath the inlet manifold, your car maybe different though. If both run then the relay is toast.

[Ski]

well my rad never turns on when engien is off.. even if engine is overheating, the rad turns off when my ignition turns off.. have i got a problem?

[iain1067]

yes your car does have this relay 447965571A control unit for water pump relay fan stage 1 relay location 14, it's a tall brown unit about 2.5 inches high. Can't help with the location of it on your car though

[iain1067]

oh and the flat battery is a classic syndrome, for me it was the rad fan it runs very quiet and i couldn't hear it hence dead battery.

[Ski]

well my rad never turns on when engien is off.. even if engine is overheating, the rad turns off when my ignition turns off.. have i got a problem?

iain1067 yes your car does have this relay 447965571A control unit for water pump relay fan stage 1 relay location 14, it's a tall brown unit about 2.5 inches high. Can't help with the location of it on your car though

was that the answer to my question or to someone else's ?

is this relay located in the fuse box?

[Martynf]

Ski,
when you switch off your ignition, the speed 2 (or 3 maybe in the recent heat!) rad fan will switch off with the ignition, speed one is very quiet with the bonnet shut you may not notice it unless you are 'looking for it!'

Get the engine hot, switch it off open the bonnet and wait a few minutes to see if the fan comes in. If it doesn't you need to work out why as it needs to turn on!!
HTH

[Martynf]

Pete,
you are welcome to come round to me and swap relay to test it. Just drop me a line to let me know when...

Martyn

I had a flat battery this week & I think I've found the culprit - my after-run coolant pump is running all the time. Any ideas what could be wrong ?

[Ski]

Ski,
when you switch off your ignition, the speed 2 (or 3 maybe in the recent heat!) rad fan will switch off with the ignition, speed one is very quiet with the bonnet shut you may not notice it unless you are 'looking for it!'

Get the engine hot, switch it off open the bonnet and wait a few minutes to see if the fan comes in. If it doesn't you need to work out why as it needs to turn on!!
HTH

it dosnt

What are the obvious I should start with? fuses?

P.S. ive only ever heard of 1 speed on my fan, never witnessed any other speeds. Thus I dont know which speed it is that keeps kicking in (when engine is on and hot (94c)).

[Martynf]

I have a 'pet theory' that most of our cars only have speeds 3 and 1 working and none of us have really noticed it!! I am pretty sure only my speed three works and 1. 2 is the most used and I reckon 'wears out' on the speed resistor and none of us really notice it and speed three tends to them kick in hard and fast and we accept that is speed 2!! it could be true.... how do you know if its speed 2 or 3 running when the fan comes on?? I've not looked into this yet, but will soon. Have you cheked through S2 central or Mikes S2 web sites to see if they have any test procedures available?