Had code P0325 so I ordered a new knock sensor. I installed it today. Cleared the code. About 10 seconds the light came back on and it was P0325 again. Cleared it again, comes back on.
When I removed the old knock sensor, no coolant came out. I put a drain pan under the engine but not a drop of coolant came out. I replaced the t-stat a few months ago and refilled the cooling system at that time. It has full coolant and doesn't overheat. I'm wondering if it's setting the knock code because there is no coolant around the sensor to dampen the knock detection? Could I have a blocked coolant passage? I couldn't see anything and had to change the sensor by feel only coming in from the passenger side along the firewall from above. Tricky to replace and am not looking forward to it again.
If I drain the coolant system tomorrow, is there a vent I can open when refilling to prevent an air pocket. I thought possibly there could be a pocket of air trapped near the knock sensor. Otherwise I'm stumped.
I have a volt meter and I'm going to test the sensor's by tapping and recording the voltage range.
Scott
2002 Audi S4, black
1996 Z24 auto, red
So my book said coolant is supposed to come out of the knock sensor port. None did. Could this be why my knock sensor code keeps popping on even with the new sensor installed?
Scott
2002 Audi S4, black
1996 Z24 auto, red
No one has a single clue?
Scott
2002 Audi S4, black
1996 Z24 auto, red
Thanks for help!
Is there a bleeder valve on a 2.4L for the cooling system?
Scott
2002 Audi S4, black
1996 Z24 auto, red
Sorry no clue > but free bump...
But just guessing if there is supposed to be coolant draining out when the knock sensor is removed it doesn't make sense that an air pocket would do it because once you remove the knock sensor that would create an area of low pressure and allow the coolant to drain. There must be a physical obstruction or something somewhere; but of course you would still have to explain why it's not overheating. Maybe check around where you replaced the t-stat.
Good luck!
No bleeder valve on the 96 that I know off, had to get the lower hose out to drain the radiator I seem to remember. Hope my knock sensor lasts a lonnnngggg time....better yet forever.
I just remove the lower hose to drain it but I didn't pull the hose to change the knock sensor.
I just unplugged it, loosened it with a 22mm deep socket, and unscrewed it by hand from the block. I had a drain pan below and not a drop came out.
I wonder if there is blockage in this engine, it's a used engine we put in last spring and it's been problem free till the knock sensor supposedly went bad. I only have changed plugs and t-stat on this engine.
Scott
2002 Audi S4, black
1996 Z24 auto, red
Scott Long wrote:
I have a volt meter and I'm going to test the sensor's by tapping and recording the voltage range.
No info on the 2.4 but the '93 3.1 should show an output of AC voltage on 2 volts scale of a multimeter, checking between knock sensor and ground, ignition ON Engine ON.
There is no reference to coolant escaping when changing/removing this sensor.
Alont
Just to add "Tap on the engine block near the sensor for an output".
Alont
Thanks I'll give it a try.
Scott
2002 Audi S4, black
1996 Z24 auto, red
