324 is not in the main fuse box it is under the dash - http://www.s2-audi.co.uk/tech_articl...dash_plate.htm Relay 14
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out of interest are there any other 324 relays to allow someone to swap over without needing to source one first?sigpic
1992 3b S2 CoupeComment
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Yeh, this failed on my S6, took an age to find it.
The fan would run for an age, and tured out something inside had burned out and my fan was spinning BUT THE PUMP WASN'T, are you sure the pump is working on your S2??? , even if not the relay could be the pump or plug corroded (had that too, it fell apart!!)
Since the fan cools the rad but the temp is taken off the water rail it will keep trying to cool itsself (is on the S6 anywho)
The relay is over £50 from audi, but are not a common failure realy, so a second hand one could be an option.
Hope this helps
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The pump is an oddity. The impellor is driven magnetically, not by a direct shaft from the motor.
Problems occur especially when cars are run - even for brief periods - without coolant additive. Pure tapwater causes corrosion within the block and other areas, and flakes of rust (even microscopic ones) wander around the system until they find the electric pump - then they crawl inside the magnetic coupling and die there, eventually clogging it up.
When testing a pump, don't just rely on it buzzing as if it's running. The motor might be, but that tells you nothing about the impellor. You need 12V and a bucket of water to test a pump.Comment
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Yes thanks, mine is all sorted now. Being a mechanic i know the importance of the system and didn't use the car untill it was sorted, my control unit had burned out half of its circuit board (amazing the fan worked at all). I bought a new unit and a new pump just to be on the safe side!! Even though the car had always had the correct VAG coolant.
Was all probably linked but the pins in the plug for the pump had corroded away, probably leading to the relay burning out! All this was after the fan fell off the fan motor and milled the end of the motor down to a point
But like i said and flaws in the cooling system should be a priority. These 5 pot engines are earth shatteringly good but bad cooling will kill any motor!!Comment
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For future reference the after-run temp switch itself can fail short too. Mine did. The relay still correctly times the on cycle but it kept coming on erratically. One to watch out for as it's not always the relay at fault. New temp switch is fairly cheap and can be replaced without draining coolant if you are sufficiently deft of hand.Comment
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If the after-run temperature sensor fails short the radiator fan and electric water pump will run for the set timer period (10 mins or so) everytime the ignition is switched off.
A mod recomended by some is to deliberatley short the temperature sensor using a fuse link or similar between the terminals so that the after-run circuit runs everytime you stop the engine rather than only running when you stop the engine if the coolant temperature reaches 105 degrees C
JohnComment
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Correct. However if your after-run temp switch can't quite make up it's mind whether it has failed short or not, it runs for 10 minutes once every 11 minutes. Guys on Quattroworld are also looking at a Volvo temp switch which is same size and fitting but has slightly lower temp rating. In UK climate my temp switch virtually never triggers the relay, and both are new so should work OK.Comment
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With that mod you'll end up with a drained battery within few hours.If the after-run temperature sensor fails short the radiator fan and electric water pump will run for the set timer period (10 mins or so) everytime the ignition is switched off.
A mod recomended by some is to deliberatley short the temperature sensor using a fuse link or similar between the terminals so that the after-run circuit runs everytime you stop the engine rather than only running when you stop the engine if the coolant temperature reaches 105 degrees C
John
If you only do long journeys then it could be fine but on a everyday basis it kills the battery within the:
Morning cappuccino stop
Newspaper stop
Groceries stop
Petrol stop
Ooopss dead battery.
StefanoComment
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As I said it is a mod recommended by some.............................
but it is ridiculous to suggest that the running of the fan on low speed and the water pump a few times a day for 11 minutes will flatten a good healthy battery.
JohnComment
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The volvo sensor is the one to have for town cars. Weekend cars can use the transporter switch
It will kill your battery on a town car on short runs not as dramatic as the other poster but cumulative after run kick bins kill the battery. Not a problem on weekend cars thoughComment
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I remember this discussion in another thread on the lower temp sensor to get the after run pump to trigger more often, it also covered the idea of the VW 1.8L 16v KR / 2.0L 16v ACE heat sensor mounted on a small bracket on the outside edge of the rocker cover of the head to run the pump based on the ambient temperature under the bonnet.
Never did anything about changing mine from oem, but all should be aware of these issues and make their own decisions.
Great forum for I5 owners.
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although it works, my after-run has never triggered in 15 years. If you look back with the search function you'll find suggestions by others for several alternative sensors including a VW 85 degreeC iirc.
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