# 2000 PAssat V6: where is the coolant temp sensor located?



## The Skeptic (May 31, 2000)

did a vag com check and i need a new coolant temp sensor.
where is it located?

if you know, please post a pic. i have an educated guess: passenger side of engine bay, down low near radiator, coming off the neck of a coolant hose. is this right?
can someone who knows for sure palse post a pic?
thanks


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## spitpilot (Feb 14, 2000)

*Re: 2000 PAssat V6: where is the coolant temp sensor located? (Haynie)*

Bad guess...I think what you're lookin at is the rad fan thermo switch. The coolant sensor is located behind the passenger side cylinder bank...pull the air intake hose and use inspection mirror to check it out. Simple replace, but you have to do it blind by feel only. You need sensor, oring and 2 clips (trust me you'll drop one and never find it







) Do the change out with engine STONE COLD....and leave coolant fill cap on tight..that way you'll lose just a few oz of coolant..just top up with distilled water! Cheap part...I bought all the stuff listed at my local dealer for about $10 or so a few years ago....so I'd guess about $15 now. http://****************.com/smile/emthup.gif


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## The Skeptic (May 31, 2000)

*Re: 2000 PAssat V6: where is the coolant temp sensor located? (spitpilot)*

thanks!


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## YavoR32 (Jul 31, 2006)

i picked up a coolant temp sensor for 40 bucks at my dealer, what a rip off, oh and no clips and no o ring, mind you its just a brass plug like thing with a green plastic connector...


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## The Skeptic (May 31, 2000)

*Re: (YavoR32)*

wow.
that part from adirondack is $15 and a few $ for the clip and such.


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## rpais (Jun 11, 2008)

There are actually 2 coolant temp sensors on the V6. One is located at the point where the coolant comes out of the radiator, (this is the one you describe) easy to see and get at. The second one is located on the back of the engine. This link is excellent in showing how to replace it: http://www.tobio.info/passat/h....html
I bought the two sensors at Autozone for about 7 bucks each. They came with a new o ring, but no clip, and yes, I did drop the clip twice and spent 30 minutes looking for it.


_Modified by rpais at 10:01 PM 6-10-2008_


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## 98blueb5 (May 12, 2008)

*Re: (rpais)*

i just replaced the one between the engine and the firewall. is the other one considered the radiator fan switch? which is on the bottom driver side of the radiator facing the engine.


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## 20th875 (Feb 11, 2004)

*Re: (98blueb5)*

Back from the dead..... I'm pretty sure this (cts) is bad on my car. I have a cold start problem. Have to crank the car over a few times before it starts, and then it acts as if it is already warm. My mechanic said that's probably what is causing the problem.
Now, for my question: I changed this in my 1.8t and lost only a drop or two of coolant (didn't need to replace any). Is it the same in this vehicle? I just did it (on the 1.8t) with the engine totally cold; didn't open the radiator cap and took out the sensor. No significant loss of fluid. Again, is it the same for the Passat or am I gonna loose a signficant amount of coolant? Any comments are appreciated.
Also, what is the difficulty rating in removing the surrounding items to get to the coolant temp switch? I did it on my 1.8t, but it looks a bit more involved on the V6. Thanks for the help.


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## VT 4-motion (Jun 14, 2009)

Will that sensor cause misfires?


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## spitpilot (Feb 14, 2000)

*Re: (VT 4-motion)*

If coolant sensor (on back of right cylinder head) is bad in the section that sends signals to the ECU..you can get weak mixture on cold starts and misfires..the sensor on back of cylinder head has two elements..one controls temp gauge reading, and one sends coolant temp signal to ECU if this one goes bad you'll get CEL since OBDII diagnostics require monitoring of engine coolant sensor in the fuel injection system..this element. If other element craps out..no CEL, but coolant temp gauge will read screwy. http://****************.com/smile/emthup.gif


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## 20th875 (Feb 11, 2004)

*Re: (spitpilot)*


_Quote, originally posted by *spitpilot* »_If coolant sensor (on back of right cylinder head) is bad in the section that sends signals to the ECU..you can get weak mixture on cold starts and misfires..*the sensor on back of cylinder head has two elements..one controls temp gauge reading, and one sends coolant temp signal to ECU if this one goes bad you'll get CEL since OBDII diagnostics require monitoring of engine coolant sensor in the fuel injection system..this element.* If other element craps out..no CEL, but coolant temp gauge will read screwy. http://****************.com/smile/emthup.gif 

Bolded above is my problem. Runs fine when warm and usually only hard to start the first time in the morning. I occasionally get a CEL but it resets and goes away.
Now, how hard is this to replace? Anyone with a DIY out there or know of one you can direct me to? I'm handy, but not a mechanic. I need to know what I'm getting myself into. Any comments and help is appreciated.


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## 20th875 (Feb 11, 2004)

*Re: (VT 4-motion)*


_Quote, originally posted by *VT 4-motion* »_Will that sensor cause misfires?

I'm not sure. It does for me when it acts up on the first start in the morning. Runs fine afte warm. I'm no mechanic, so I'm not sure I've answered your question. Hope that helped.


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## spitpilot (Feb 14, 2000)

*Re: (20th875)*


_Quote, originally posted by *20th875* »_
Bolded above is my problem. Runs fine when warm and usually only hard to start the first time in the morning. I occasionally get a CEL but it resets and goes away.
Now, how hard is this to replace? Anyone with a DIY out there or know of one you can direct me to? I'm handy, but not a mechanic. I need to know what I'm getting myself into. Any comments and help is appreciated.
 Its about a 15-30min job...depending on how good you are with your hands...blindfolded!







You can't see what you're doin..have to do everything by "braile"...since sensor location is down out of sight behind right cylinder head...Thanks VW! http://****************.com/smile/emthdown.gif I used an inspection mirror to get the "lay of the land" B4 I stuck my hand down there....You must do this job with engine "stone cold"....to avoid losing coolant..and frying your fingers! Keep coolant cap on tight and you'll lose only a few OZ in the process..I just topped up with distlled water. There is a plastic clip holding sensor in socket..you just use a stubby screwdriver to pry it off and pull sensor out...make sure O ring comes with sensor..if not use a pick to get it outa the socket...Put some silicone grease or dishwashing liquid on the new O ring to make it ez to push sensor in socket..replace clip...beware...clip falls it goes into never/never land somewhere over the tranny...I lost one..so buy two along with sensor and oring..all parts are less than $15...I tied a string on my second clip so I could fish it back up if I dropped that one too!


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## 20th875 (Feb 11, 2004)

*Re: (spitpilot)*


_Quote, originally posted by *spitpilot* »_ Its about a 15-30min job...depending on how good you are with your hands...blindfolded!







You can't see what you're doin..have to do everything by "braile"...since sensor location is down out of sight behind right cylinder head...Thanks VW! http://****************.com/smile/emthdown.gif I used an inspection mirror to get the "lay of the land" B4 I stuck my hand down there....You must do this job with engine "stone cold"....to avoid losing coolant..and frying your fingers! Keep coolant cap on tight and you'll lose only a few OZ in the process..I just topped up with distlled water. There is a plastic clip holding sensor in socket..you just use a stubby screwdriver to pry it off and pull sensor out...make sure O ring comes with sensor..if not use a pick to get it outa the socket...Put some silicone grease or dishwashing liquid on the new O ring to make it ez to push sensor in socket..replace clip...beware...clip falls it goes into never/never land somewhere over the tranny...I lost one..so buy two along with sensor and oring..all parts are less than $15...I tied a string on my second clip so I could fish it back up if I dropped that one too!









OK. When you say "right cylinder head" is that as you look at the engine from the front of the car, or is that sitting in the drivers seat looking forward? (my understanding is it is located at the rear of the engine and you must remove the airbox in order to get to it. Any additional comments would be most helpful. Thanks spitpilot.


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## spitpilot (Feb 14, 2000)

*Re: (20th875)*

By "right" I meant "passenger side" cylinder head...pull the flex duct from the mass airflow sensor to the throttle body inlet....put inspection mirror down there and you'll see a metal pipe running horizontally with sensor socket on top..electrical connector and wires of course..that's the culprit! http://****************.com/smile/emthup.gif


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## Slimjimmn (Apr 8, 2006)

*Re: (spitpilot)*

its the 4 pin sensor, and it helps to remove the 13mm bolt for the ps line next to it and the 10mm on the valve cover to push the line out of the way.


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## 20th875 (Feb 11, 2004)

*Re: (Slimjimmn)*


_Quote, originally posted by *Slimjimmn* »_its the 4 pin sensor, and it helps to remove the 13mm bolt for the ps line next to it and the 10mm on the valve cover to push the line out of the way. 

Slimjimmn and Spitpilot, sounds fairly straight forward for a somewhat handy person. Is that right, I should be able to do it fairly easy? Thanks for all the comments.


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## spitpilot (Feb 14, 2000)

*Re: (20th875)*

About the eziest repair I've ever done on a car..except for the "flying blind" part..just be patient and like I suggested, tie a string on the little lock clip and around your wrist so you can retreive it if it drops during install...I just cut the string off afterward with a razor blade...Just be sure to double check you've got the old oring out..it either comes out on old sensor or stays in the sensor socket..in which case you have to use a pick to "fish it out"...only room for one O ring in there at a time!


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## tomwin (Jun 26, 2009)

*Re: 2000 PAssat V6: where is the coolant temp sensor located? (Haynie)*

I can't answer your question, but I'd like to ask you a question. I'm trying to find out if my problem is the problem solved by replacing the coolant temp sensor.
my dash board tells me it's 25 degrees F outside when it's in the 70's... and then the AC doesn't work.
is this the problem you were having?
thanks in advance


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## spitpilot (Feb 14, 2000)

*Re: 2000 PAssat V6: where is the coolant temp sensor located? (tomwin)*

Air temp sender is down in front by radiator mount....not the same as engine coolant sender! As far as AC goes...not sure if sender outside air is connected to AC control or not...could be in the "climatronic system"....you'll have to change the ambient air sender to find out! http://****************.com/smile/emthup.gif


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## 20th875 (Feb 11, 2004)

*Re: 2000 PAssat V6: where is the coolant temp sensor located? (spitpilot)*

Well, I'm trying to do this repair now. When I finally figured out where this part (CTS) was located at (camoflaged by a black connector top and the great difficulty to get some light on it), the new part AND the washer will not fit in so I can get the clip on (sits too high). Strange thing, there was no rubber washer on the old part so maybe I'm not supposed to put the washer in now? Anybody know the answer to the question? I need to get this car back together.
Thanks for your help.


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## 20th875 (Feb 11, 2004)

*Re: 2000 PAssat V6: where is the coolant temp sensor located? (20th875)*

I was able to trouble shoot the problem. See this thread for all you probably ever want to know about the CTS.
http://forums.vwvortex.com/zerothread?id=4482972


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