Need help getting Coolant Temp Sensor out!
04-05-2006, 11:54 AM
#43
2nd, LOL- Take a picture of what you got from the Stealer Ship. Sounds like it's
<center><img src="http://www.ecstuning.com/stage/images/product/iadmin/1117_x450.jpg"></center><p>thermostat and not a CTS. The CTS should look like this.
04-05-2006, 01:19 PM
#48
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Instructions for changing coolant temperature sensor:
I had been having some problems with my temperature gauge <a href="https://forums.audiworld.com/s4/msgs/2291251.phtml">as described here</a>. Several people suggested the coolant temperature sensor as a likely culprit, so I changed it today and created this write-up in case it's helpful to others.
Car: 2001 S4 tip, old style badge
Tools used: two pairs of vice grips, one with wide jaws; small and medium sized flathead screwdrivers.
Parts (dealer name for parts given in ""):
* Coolant temperature sensor ("temperature sender"), 059-919-501-A. Beware: there is another coolant temperature sensor with almost the same part number, but without the "A". I was told it's for an earlier model Audi.
* Rubber o-ring ("seal"), N-903-168-02
* U-clip ("spring"), 032-121-142
Total cost of parts was about $10.
The new temperature sensor is shown below (the pencil is for scale), together with the o-ring (attached) and the plastic U-clip:
<img src="http://pictureposter.audiworld.com/8418/coolant_temperature_sensor_new_s.jpg">
Note that it's green, although the original part being replaced is black. Bottom view of the temperature sensor; note that one side is flat:
<img src="http://pictureposter.audiworld.com/8418/coolant_temperature_sensor_new2_s.jpg">
I started by removing the black plastic accordian hose that fits onto the engine's air intake (see photo of engine bay below); the parts being replaced lie underneath this. At either end of the hose there are powerful metal clamps you need to loosen and remove. I used vice grips. The right-hand clamp required an extra-wide-jawed vice grip.
<img src="http://pictureposter.audiworld.com/8418/engine_bay_s.jpg">
Photo of left-hand clamp in vice grip:
<img src="http://pictureposter.audiworld.com/8418/intake_hose_clamp_and_vice_grips_s.jpg">
In the above photo of the engine bay, you'll notice that between the ends of the air intake there is a slender black hose wrapped in silver heat-reflective foil, and in front of this is a wire harness with a blue section. In my car, these were directly in the way of accessing the coolant sensor; I don't know if this is due to the car being tiptronic or not. Here's another photo of the miscreant hose & harness (I removed the silver foil, it just attaches with studs); the wire harness for the coolant sensor is visible underneath:
<img src="http://pictureposter.audiworld.com/8418/hoses_in_the_way_s.jpg">
I next removed the U-clip that holds the coolant sensor in place. The following photo was taken from the car's right-hand side: the U-clip is the in-focus rounded plastic part, beneath and to the right of the out-of-focus black hose:
<img src="http://pictureposter.audiworld.com/8418/spring_s.jpg">
Facing the car with your knees against the bumper, the clip pulls out in a direction of 5-o'clock to 11-o'clock. With the U-clip gone, I tried removing the coolant sensor but it wouldn't budge, so I next removed two wire harnesses, one from the "hose" with the blue section, and the other one from the coolant sensor. I did this by gently prising up and off the top part of the sensor harness clip. The old coolant sensor now becomes visible (bottom center of photo):
<img src="http://pictureposter.audiworld.com/8418/sensor_with_wire_harness_removed_s.jpg">
I found the coolant sensor difficult to remove. There's little room to work in, and I couldn't pull it off with pliers. Eventually, I took a medium-sized flathead screwdriver and worked it around the gap between the sensor and the rim of its receptacle, prising it off. The receptacle now becomes visible:
<img src="http://pictureposter.audiworld.com/8418/receptacle_for_coolant_temperature_sensor_s.jpg">
The old coolant sensor had corrosion around its wet end:
<img src="http://pictureposter.audiworld.com/8418/coolant_temperature_sensor_old_s.jpg">
The old o-ring was still in place, so I had to hunt around for it in the receptacle with my fingers. For comparison, old (left) and new (right) parts:
<img src="http://pictureposter.audiworld.com/8418/coolant_temperature_sensors_old_and_new_s.jpg">
The rest was pretty straight forward. I cleaned up the receptacle to remove the corrosion, and added a little water so there wouldn't be an air bubble trapped there. I next fitted the o-ring and pushed it into place, the coolant sensor (flat side faces the car battery), its U-clip, and the wire harnesses. After I replaced the air intake accordian hose I was done (the clamps were a pain).
Rory
Car: 2001 S4 tip, old style badge
Tools used: two pairs of vice grips, one with wide jaws; small and medium sized flathead screwdrivers.
Parts (dealer name for parts given in ""):
* Coolant temperature sensor ("temperature sender"), 059-919-501-A. Beware: there is another coolant temperature sensor with almost the same part number, but without the "A". I was told it's for an earlier model Audi.
* Rubber o-ring ("seal"), N-903-168-02
* U-clip ("spring"), 032-121-142
Total cost of parts was about $10.
The new temperature sensor is shown below (the pencil is for scale), together with the o-ring (attached) and the plastic U-clip:
<img src="http://pictureposter.audiworld.com/8418/coolant_temperature_sensor_new_s.jpg">
Note that it's green, although the original part being replaced is black. Bottom view of the temperature sensor; note that one side is flat:
<img src="http://pictureposter.audiworld.com/8418/coolant_temperature_sensor_new2_s.jpg">
I started by removing the black plastic accordian hose that fits onto the engine's air intake (see photo of engine bay below); the parts being replaced lie underneath this. At either end of the hose there are powerful metal clamps you need to loosen and remove. I used vice grips. The right-hand clamp required an extra-wide-jawed vice grip.
<img src="http://pictureposter.audiworld.com/8418/engine_bay_s.jpg">
Photo of left-hand clamp in vice grip:
<img src="http://pictureposter.audiworld.com/8418/intake_hose_clamp_and_vice_grips_s.jpg">
In the above photo of the engine bay, you'll notice that between the ends of the air intake there is a slender black hose wrapped in silver heat-reflective foil, and in front of this is a wire harness with a blue section. In my car, these were directly in the way of accessing the coolant sensor; I don't know if this is due to the car being tiptronic or not. Here's another photo of the miscreant hose & harness (I removed the silver foil, it just attaches with studs); the wire harness for the coolant sensor is visible underneath:
<img src="http://pictureposter.audiworld.com/8418/hoses_in_the_way_s.jpg">
I next removed the U-clip that holds the coolant sensor in place. The following photo was taken from the car's right-hand side: the U-clip is the in-focus rounded plastic part, beneath and to the right of the out-of-focus black hose:
<img src="http://pictureposter.audiworld.com/8418/spring_s.jpg">
Facing the car with your knees against the bumper, the clip pulls out in a direction of 5-o'clock to 11-o'clock. With the U-clip gone, I tried removing the coolant sensor but it wouldn't budge, so I next removed two wire harnesses, one from the "hose" with the blue section, and the other one from the coolant sensor. I did this by gently prising up and off the top part of the sensor harness clip. The old coolant sensor now becomes visible (bottom center of photo):
<img src="http://pictureposter.audiworld.com/8418/sensor_with_wire_harness_removed_s.jpg">
I found the coolant sensor difficult to remove. There's little room to work in, and I couldn't pull it off with pliers. Eventually, I took a medium-sized flathead screwdriver and worked it around the gap between the sensor and the rim of its receptacle, prising it off. The receptacle now becomes visible:
<img src="http://pictureposter.audiworld.com/8418/receptacle_for_coolant_temperature_sensor_s.jpg">
The old coolant sensor had corrosion around its wet end:
<img src="http://pictureposter.audiworld.com/8418/coolant_temperature_sensor_old_s.jpg">
The old o-ring was still in place, so I had to hunt around for it in the receptacle with my fingers. For comparison, old (left) and new (right) parts:
<img src="http://pictureposter.audiworld.com/8418/coolant_temperature_sensors_old_and_new_s.jpg">
The rest was pretty straight forward. I cleaned up the receptacle to remove the corrosion, and added a little water so there wouldn't be an air bubble trapped there. I next fitted the o-ring and pushed it into place, the coolant sensor (flat side faces the car battery), its U-clip, and the wire harnesses. After I replaced the air intake accordian hose I was done (the clamps were a pain).
Rory
10-18-2023, 10:23 AM
#50
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Then once you locate the sensor, remove the wire connecting the sensor. Then pull out the c-clip and pull on the sensor (make sure you catch the 0-ring with it). Now do the reverse to put the new one in and you're done. Don't forget to put the o-ring back on the new one.
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