Engine Coolant Temp. Sensor

Anomie

Veteran Member
Joined
Jul 4, 2009
Location
San Diego
TDI
09 Jetta DSG
todhog said:
...It didn't truly overheat. As soon as the red light came on and it beeped...
Not to be a pessimist but those lights aren't called idiot lights for nothing. Double check for your sake, it won't hurt to take a look at the coolant and confirm no changes in color/opacity.
 

adamant628

Veteran Member
Joined
Jul 20, 2009
Location
Columbus, OH
TDI
2003 Jetta Wagon GLS
Is the OEM from idparts worth twice as much as the non-OEM? Just wondering if I should spring the extra bucks for the more expensive part.

The OEM is ~$25 with clip and O-ring from impex, and $34 from idparts. Idparts.com also has a non-OEM for $16
 
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TonyJetta

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Joined
Sep 15, 2005
Location
Tucson, Az
TDI
'15 Jetta TDI SE / '06 Jetta TDI DSG Pkg0 / '96 Passat TDI
The non-oem from idparts is usually from the german aftermarket, and in most cases is not an issue to use.

Tony
 

adamant628

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Joined
Jul 20, 2009
Location
Columbus, OH
TDI
2003 Jetta Wagon GLS
Should I be replacing the thermostat as well? I haven't noticed my oil temp changing, and the water temp on scangauge is always right around the same temp as well.
 

TonyJetta

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Joined
Sep 15, 2005
Location
Tucson, Az
TDI
'15 Jetta TDI SE / '06 Jetta TDI DSG Pkg0 / '96 Passat TDI
What IS the temperature? If it is holding ~188F/87C, then don't bother. If, after a full & normal warm up cycle, the temp is lower or higher by ~15F/8C, then I might consider changing it.

Tony
 

adamant628

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Joined
Jul 20, 2009
Location
Columbus, OH
TDI
2003 Jetta Wagon GLS
It doesn't seem to move much from 188-190. I'll start with the sensor, and watch closely.

Thanks for the help.
 

TonyJetta

Top Post Dawg
Joined
Sep 15, 2005
Location
Tucson, Az
TDI
'15 Jetta TDI SE / '06 Jetta TDI DSG Pkg0 / '96 Passat TDI
adamant628 said:
It doesn't seem to move much from 188-190. I'll start with the sensor, and watch closely.
Normal thermostat temp!
 

adamant628

Veteran Member
Joined
Jul 20, 2009
Location
Columbus, OH
TDI
2003 Jetta Wagon GLS
Finally getting around to doing this soon. How does the wiring disconnect from the sensor? I want to disconnect the wiring and reconnect it to the new one before actually pulling the sensor, right?

Thanks
 

TonyJetta

Top Post Dawg
Joined
Sep 15, 2005
Location
Tucson, Az
TDI
'15 Jetta TDI SE / '06 Jetta TDI DSG Pkg0 / '96 Passat TDI
It's easier if you disconnect it after changing the sensor; the wiring acts as a leash for the sensor.

Tony
 

JB05

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Joined
Oct 20, 2005
Location
Il.USA
TDI
Golf,2005,anthracite blue
You can practice on the MAF sensor to disconnect the CTS, but I just use a screw driver. I also did the leash technique that TJ recommends.
 

adamant628

Veteran Member
Joined
Jul 20, 2009
Location
Columbus, OH
TDI
2003 Jetta Wagon GLS
OK so just to make sure I've got this straight.

My planned course of action:
1. Tilt car up on Driver's side.
2. Place a plastic garbage bag opened under the sensor.
3. Make sure O-ring is seated on the new sensor. (Should I moisten it with some coolant or water?)
4. Pull the clip (is this the clip that needs to be pried with a screwdriver?)
5. Pull the old sensor and put the new one in ASAP.
6. Replace the clip
7. Pull wiring harness off of old, attach to new. (Does it clip or just slide on or off?)
8. Pour captured coolant back into the reservoir.
9. Drive?

JB05 do you mean uncliping the MAF from the air hose?
 

sfierz

Veteran Member
Joined
Jan 21, 2001
Location
Rockford, Illinois
TDI
1996 Tornado Red Passat
You may want to put a clear gallon baggy under the temp sensor location so you can recover some of the coolant that WILL come out. Or, you can just drain all the coolant and not have to rush or lose any.

You may have to fish the old O-ring out while the coolant is spilling out. This can be a nuisance. It doesn't always come out with the old sensor.

adamant628 said:
OK so just to make sure I've got this straight.

My planned course of action:
1. Tilt car up on Driver's side.
2. Place a plastic garbage bag opened under the sensor.
3. Make sure O-ring is seated on the new sensor. (Should I moisten it with some coolant or water?)
4. Pull the clip (is this the clip that needs to be pried with a screwdriver?)
5. Pull the old sensor and put the new one in ASAP.
6. Replace the clip
7. Pull wiring harness off of old, attach to new. (Does it clip or just slide on or off?)
8. Pour captured coolant back into the reservoir.
9. Drive?

JB05 do you mean uncliping the MAF from the air hose?
 

adamant628

Veteran Member
Joined
Jul 20, 2009
Location
Columbus, OH
TDI
2003 Jetta Wagon GLS
I did this last week finally. I jacked up the driver's side and put a bag under the sensor. I missed most of what drained out, but it seemed pretty minimal. I was able to yank the sensor with my left hand reaching around behind, and put in the new one with my right hand. I think I had it sealed back up in less than 10 seconds. Barely lost anything! I had one CEL as soon as I started it up, but I attributed that to having unplugged the sensor, cleared it and haven't had a problem since. (including the glow plug light staying on too long occasionally).

Thanks for the help guys!
 

Anomie

Veteran Member
Joined
Jul 4, 2009
Location
San Diego
TDI
09 Jetta DSG
adamant628 said:
...cleared it and haven't had a problem since. (including the glow plug light staying on too long occasionally).
Yeah the ECT is that important to engine operation, right up there with the CKP and CMP. A proper reading will mean proper GP on-time cycles. Glad to hear all went well. :D
 

eGolf

Well-known member
Joined
Oct 27, 2005
Location
Newark, Delaware
TDI
N/A
Hey guys, I just replaced my ECT and I got a code after replacing it. Couldn't check it at the time, but it's been a day or so (and a few engine cycles) and it's 16502 - Signal Too High. I have vagcom re-installed, so I try clearing it and it just stays there.

Any ideas? Could it be a bad part? I got it from idparts, aftermarket to save $.
 

eGolf

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Joined
Oct 27, 2005
Location
Newark, Delaware
TDI
N/A
It's reading normal, but I haven't verified the "actual" temp in vag com. I have noticed that when I start the car it revs real quick before going back to idle, as if I blipped the throttle. I'll check actual temperature at lunch if I can get the car warmed up enough.

Replaced it due to erratic temperature readings on the gauge in the car.
 

eGolf

Well-known member
Joined
Oct 27, 2005
Location
Newark, Delaware
TDI
N/A
Instrument, Block 3 = 80-82deg after a jaunt to McD's. Should I suspect a thermostat issue as well as this sensor potentially being bunk?
 
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