coolant temperature sensor location

MOGolf

Top Post Dawg
Joined
Jun 27, 2001
Location
underneath something
TDI
2001 Golf GLS TDI Reflex silver, rough road suspension and steel skid plate, 2004 Passat Variant, Candy White, rough road suspension and geared balanced shaft module, and much, much more. 2016 LR RR HSE TD6, 2019 Jaguar I-PACE
Your black one is superceded by the green one.
 

Jettawolfs98

Veteran Member
Joined
Nov 14, 2003
Location
Omaha,NE
TDI
JETTA TDI 2009, JSW 2013 DSG PANO
Yeah I check the parts service at the dealer and they told me that, but the part number on the old sensor is
078 919 501C kind of black.

Not 078 919 501B....Blue temperature sensor (20.80)

See the last letter is different from C (mine) to B for the blue sensor.

And the new one id059 919 501A....Green temperature sensor (3.62)

So that means that the green is the right one for my car like Mogolf just mentioned.
but I still can't get the sensor out of the electric connector, man starts to
off.

The sensor has a piece that makes it to hold the electric thing. so you have to push that thing down and the pull the sensor, right or I'm wrong?

Well if somebody can you tell whay I'm doing wrong one more time, I'll try tomorrow morning.

Thanks and have a good night.

Ahh just just my bentley manual today a lot of info too.
 

Jettawolfs98

Veteran Member
Joined
Nov 14, 2003
Location
Omaha,NE
TDI
JETTA TDI 2009, JSW 2013 DSG PANO
Finally got it out !!!!!!

That sensor is very easy, once you have the right tools.

I went to Sears to get a small point driver and just push the clip and the sensor went out very easy.

My only question is:

The mix with water and coolant was 50%-50% it's that OK.

Please let me know, because doesn't looks like very thick.

Now I need a Vag-Com to clear the bad code.
 

Jettawolfs98

Veteran Member
Joined
Nov 14, 2003
Location
Omaha,NE
TDI
JETTA TDI 2009, JSW 2013 DSG PANO
It's ok to drain some coolant and add more without the mix water-coolant only coolant?

The winter is coming and I don't want to have any problems.

 

robnitro

Veteran Member
Joined
Jan 19, 2004
Location
NYC area, NY
TDI
2001 Jetta TDI GLS silver
Well, if stock is 50-50... and you drain a quart and put in coolant, it should be still less than 70-30, which is fine. More lubrication for the water pump anyhow!
 

shmcquilkin

Veteran Member
Joined
Oct 28, 2002
Location
Maine
TDI
2016 E63S estate, 1995.5 S6 avant, 1987 Vanagon Syncro GL, 1971 Westfalia
Been throwing CELs for high and intermittent temp sensor readings, which luckily did not affect my gauges, and finally found these threads. New, Green sensor for my '03 Jetta + clip and o-ring (just in case) was $10 shipped from Impex. Took me about 9 minutes to do:
- Removed engine cover and accordian, intake hosing
- Keeping old sensor attached to plug I pulled the clip and slowly pulled the sensor out with right hand, with an angle of attack from below and on the driver's side.
- Immediately stuck my left index finger "in the dike" to stem the loss of coolant from up and over the valve cover and CCV puck.
- Looked at the sensor I had just removed to confirm that the o-ring did not come out... of course!

This old one was a Black 4-pin OEM, being replaced with a Green 4-pin one... PLEASE READ ASSOCIATED THREADS linked in this thread ABOUT THIS!!
- Took new sensor, w/ o-ring locked-and-loaded already
in right hand and did the quick switch-a-roo, pulling the old o-ring out when I removed my left finger.
- Replaced the clip
- Now, I took the old sensor off of the plug, packed the plug with dielectric conducting goo, and clipped it back on the new, Green sensor.
- Lost about 1/2 cup of coolant via this "wet" method.
- Topped off with G12/distilled water mix
- Reset the fault codes with Vag-Com
- Wa-la!!

It does seem to help to NOT undo the coolant resevoir cap!

PLEASE only perform this on a COLD car, just to reiterate!

THANKS FOR THE HELP GANG!!!

Peace

Another assoc. thread with links:
http://forums.tdiclub.com/showflat.php?C...true#Post772571
 

sootandclatter

Veteran Member
Joined
Mar 5, 2002
Location
sootland
To avoid a mess, remove cap at resovouir, squeeze top rad hose and hold, reinstall resovour cap, remove squeeze from hose. this puts a vacuum in system and no fluid will come out of sensor hole when sensor is removed, still don't drink a beer or have a smoke, get the job done.
 

nicklockard

Torque Dorque
Joined
Aug 15, 2004
Location
Arizona
TDI
SOLD 2010 Touareg Tdi w/factory Tow PCKG
Damn! I wish I had thought of that when I did mine grrr....



Lost a quart or more....

Oh well.
 

shmcquilkin

Veteran Member
Joined
Oct 28, 2002
Location
Maine
TDI
2016 E63S estate, 1995.5 S6 avant, 1987 Vanagon Syncro GL, 1971 Westfalia
LOL, owe you a frosty for that one Velvet! Was going to do this last night after driving home, but reread the *whole* thread just before doing it. Didn't know the potential flow would be as much as it could. Also didn't realize how much of my finger would lodge up in there. Yowzers, that would of STUNG if it was at temp!


Arg... Great call sootandclatter!!!
 

MJA

Member
Joined
Mar 27, 2003
Location
Kalamazoo, MI
Did you know that you can use Seira propylene glycol? It doesn't contain any phosphates and is way cheaper than dealer coolant.
Best,
Mark
 

tadc

Top Post Dawg
Joined
Apr 13, 2001
Location
Stumptown
TDI
Golf GLS TDI, '01, Black
Uhhh, says who? AFAIK no "green" coolant should be mixed with the pink stuff.
 

Spokane Walt

Veteran Member
Joined
May 10, 2006
Location
Washington State, USA
TDI
2000 Jetta Sedan GLS TDI 5sp, 2000 Jetta 2.0 AEG Gas, 2003 Jetta TDI Wagon 5sp (wrecked - have some parts!)
140 Deg Temp Sensor

O Ya, Does anyone know why the new green sensor says 140 deg Max on the side? [/quote]


I think that means that the max it will read and still differentiate is 140 Deg - which likely means that if you get your temp above 140 deg C (not Deg F), it can't tell if it is 141 or 151 or 200 - it just knows it is above 140.

Just an educated guess - it your collant reaches 140 Deg C, you have much bigger problems anyway...

Walt in Spokane
 

BinTHEgrove

Active member
Joined
Jun 15, 2006
Location
Minneapolis, MN
TDI
03 GLS TDI
I just did this, and what a mess... dropped the sensor and wow did it flow out, no tablespoon or to for me. I released the pressure and everything I read in this post. No luck, antifreeze everywhere and I did it quick for the most part. Anyway, I put the clip back in and I can see it barely on the top like it went through the first set of grooves but not the second, is that correct. For some reason I can remember... I wiggled the sensor and it doesnt' seem to go anywhere.

Thanks for any help.
 

frugality

Top Post Dawg
Joined
Sep 19, 2003
Location
Spring Lake, Michigan
TDI
none, 2016 GTI
Thanks for all the above posts. They came in handy in my own coolant temperature sensor swap. I'll copy-paste the comments the comments I made on this thread: http://forums.tdiclub.com/showthread.php?t=190500

frugality said:
This is just an FYI post for anyone replacing a coolant temperature sensor.

Long story short, my 2000 Golf TDI developed a problem where the temp gage needle wouldn't go up to the center 190 mark. Occasionally it was a little shy, and a few times it was a full two hashmarks low on the gage. I suspected a bad thermostat, because I've heard that VW thermostats are designed to fail in the 'open' position, and therefore err on the side of being too cool. However, in doing some searching here, I found that the temperature sensor may be the problem. Seems that the sensors were more prone to failure than thermostats are.

One suggestion came up on a thread that you didn't have to drain the coolant -- just pull the old sensor and be prepared to plug in the new one quickly as coolant starts to come out. This worked O.K., but I want to post a warning. I pulled the old one, and quickly jammed in the new one, only to find that the old one that was now in my hand didn't have the O-ring on it. It had stayed inside the casting, and I'd jammed the new one in with its new O-ring, so now there were 2 O-rings in there. So I had to pull it out again and fix things, and meanwhile I dumped a bunch of coolant. Still, with all that, I didn't lose enough coolant to have to top up right away. The level went from close to the sensor on the reservoir down to just above the hatched 'minimum' area.

The basic procedure:
* Let the engine cool. I waited 2 hours from being hot, and the coolant was bathwater warm. (and my hands did get bathed)
* Remove engine cover.
* Open the cap on the coolant reservoir to release any pressure in the system. Then close it again.
* Unplug the old sensor. This was kind of a bugger. I ended up getting it loose by putting a small screwdriver into the area where the release tab is, and then twisting the screwdriver to push on the tab. Having a look-see with a small mirror beforehand is helpful.
* Plug your new sensor into the wire harness.
* Remove the plastic 'C' clip that retains the old sensor. Be carful not to drop it, because it's plastic and you can't fish it out with a magnet.
* Hug your engine. With one hand you'll remove the old sensor, and with the other hand you'll plug in the new sensor, as coolant starts to pour out. You may have to fish out your old O-ring like I did, in which case you'll loose a couple cups of coolant.
* Replace plastic C-clip.
* Check and add coolant if necessary.
* Start engine and check for leaks.
* Pat yourself on the back.

I'll have to watch for the next few days, but this seems to have fixed the problem. Twice now the temp gage goes right up to 190 and stays there. It's nice to have a quick, cheap fix.

Also as a side note, my 2000 Golf was made in 12/1999, so it should have had the blue, square temperature sensor. Later models have a rounded green sensor. However, mine was black, and was rounded -- sort of a D-shape. Maybe mine was different because my car was German-made.

My local dealer quoted $34 for the sensor, which they had in stock. I got mine for $14+shipping at tdiparts.com. I also got an extra O-ring for $1, and that was a good idea. I lost one down below the engine when I fumbled around removing the new sensor to get the old O-ring out.
 

Harvieux

Vendor , w/Business number
Joined
Aug 15, 1998
Location
Whittier,CA-USA
TDI
06 A5 Pkg.2 w/navi & ASEP
I did not read this entire thread to see if anyone has mentioned the procedure I use to make this switch alot easier so, here we go. Actually, I copied and pasted this from a response to Dean (frugality) in another post. Later!

Dean, Most of what you post here in this procedure is correct. One thing I would change is as follows: Pull the plastic horseshoe clip which holds the sensor. Note how the sensor is currently positioned. Usually the flat side of the sensor is facing down and the rounded side is up. Have the new sensor with o-ring attached and then pull out the old sensor with the electrical connecter still attached to it. Be sure the old o-ring is removed (as you found out the hard way) and quickly replace with the new sensor and o-ring in the correct position referenced above. Snap the horseshoe clip in and you can now relax while removing the electrical plug from the old sensor because you now have much better access to it without having to struggle removing it off the old sensor as you also discovered. Later!
 

Harvieux

Vendor , w/Business number
Joined
Aug 15, 1998
Location
Whittier,CA-USA
TDI
06 A5 Pkg.2 w/navi & ASEP
BTW, The older 1Z, AHU, and early ALH had a square electrical plug for the CTS however, the above procedure of removeing the CTS with the elecrtical connector plugged in would still be applicable with the early ALH's. Later!
 

ChrisB.

Veteran Member
Joined
Jun 14, 2000
Location
Bel Air, Md.
TDI
Stepfather of an '03 Jetta TDI, still miss my chipped 1999 Bright Blue NB Totaled 10/2011; 2011 TR GTI, 1998 NB 2.slo0
Just did my ECT sender on my early 99 NB. Piece of cake. Dealer first gave me the green replacement (059-919-501A), so I had to go back and trade it for a blue square one (059-919-501) like Harvieux says. I also picked up an extra C clip in case I broke the original. Smart insurance, though not needed this time.

For a NB, helpful tips are to remove the intake hose, disconnect the coolant glow plugs, and remove the top half of the air filter box. Getting this stuff out of the way makes it easier for a quick-swap to minimize the coolant loss.

After removing the electrical connector and the retaining clip, count on fishing the old O ring out of the housing.

Not sure if it is is the placebo effect, but I find the car runs better with the new ECT sender. Possible explanation, perhaps now I'm getting a correct fuel mixture based on the correct coolant temperature. Either way, no more blue flashing coolant light. Thoughts?
 

rudolfgreen

Active member
Joined
Oct 28, 2006
Location
Waialua, HI
TDI
04 Jetta Manual BEW, 83 Vanagon 5spd 1.6NA, 86 Vanagon Syncro ALH (Sold)
idiots guide to the coolant temperature sensor (CTS)

a solid thread.
 

SheeB

Veteran Member
Joined
Jul 8, 2007
Location
Ottawa, ON
TDI
2001 Jetta GLS Manual
BinTHEgrove said:
I released the pressure and everything I read in this post. No luck, antifreeze everywhere and I did it quick for the most part.
I replaced my CTS as well today and followed the steps to unscrew the coolant cap and release pressure then squeezed upper rad hose, then tighten coolant cap. Also removed the accordian air intake hose. As soon as I wiggled out the sensor, a nice steady stream of pink stuff came out and I had to struggle quickly to remove the old o-ring that stayed inside. :eek: Lost about 1 litre of coolant but I had more than enough replacement coolant on hand so no issues. If it were not for the o-ring I would have lost minimal coolant. The plastic clip came off rather easily with my fingers too, but again had spare handy which I used anyways. Washed everything with a bucket of water afterwards to clean off coolant off motor. 15 minute job. Thanks for all the write ups on this task!
 

bdl1989

Member
Joined
Nov 13, 2008
Location
Abbotsford BC CANADA
TDI
2002 Jetta TDI
shmcquilkin said:
Been throwing CELs for high and intermittent temp sensor readings, which luckily did not affect my gauges, and finally found these threads. New, Green sensor for my '03 Jetta + clip and o-ring (just in case) was $10 shipped from Impex. Took me about 9 minutes to do:
- Removed engine cover and accordian, intake hosing
- Keeping old sensor attached to plug I pulled the clip and slowly pulled the sensor out with right hand, with an angle of attack from below and on the driver's side.
- Immediately stuck my left index finger "in the dike" to stem the loss of coolant from up and over the valve cover and CCV puck.
- Looked at the sensor I had just removed to confirm that the o-ring did not come out... of course!

This old one was a Black 4-pin OEM, being replaced with a Green 4-pin one... PLEASE READ ASSOCIATED THREADS linked in this thread ABOUT THIS!!
- Took new sensor, w/ o-ring locked-and-loaded already
in right hand and did the quick switch-a-roo, pulling the old o-ring out when I removed my left finger.
- Replaced the clip
- Now, I took the old sensor off of the plug, packed the plug with dielectric conducting goo, and clipped it back on the new, Green sensor.
- Lost about 1/2 cup of coolant via this "wet" method.
- Topped off with G12/distilled water mix
- Reset the fault codes with Vag-Com
- Wa-la!!

It does seem to help to NOT undo the coolant resevoir cap!

PLEASE only perform this on a COLD car, just to reiterate!

THANKS FOR THE HELP GANG!!!

Peace

Another assoc. thread with links:
http://forums.tdiclub.com/showflat.php?C...true#Post772571
Is it true you need to reset the codes with Vag-com when finished, or should the light go out on its own?
 

Dodoma

Veteran Member
Joined
Mar 30, 2004
TDI
2002 Jetta White
cts

if your temperature needle behaves erratic, sometime remains unmoved, sometime shoots to 190, sometimes toggles between these two temp numbers (0 or 190), and there is MIL, try fixing this problem by replacing the coolent temperature sensor. You can get the sensor from Autozone for about $10. Read his site on how to replace the sensor. It capture snd resuse the coolent that would come out when the sensor is removed, use plastic grocery bag by keeping it wide opening directly underneath the sensor. My original sensor lasted about 115,000 miles for my 2002 TDI Jetta. It was black part number 078919501C. The new one was green from Autozone but did not had VW part number. New rubber "O" ring is slightly thick and this will be a problem in putting back the plastic U-clip. To address this problem, smear the "O" ring with some armor oil (the one we use for vinyl).
 

logos

Veteran Member
Joined
Sep 3, 2005
Location
Anchorage, AK
TDI
2004 Jetta Wagon TDI 5A. Previous car: 2001 Golf, 5spd
old sensor won't come out

Hi,
My golf has been having difficulty starting (loottts of cranking and smoke when we are at a high altitude in CO and it is cold) and since the coolant temp sensor is now ten years old, and it isn't the approved green kind, I figured it couldn't hurt to replace it.
I got the plastic clip off (it broke of course) and the tabs on the connector have been broken for years so that just slips off. But the sensor will not come out. I can just rotate the plastic part of the sensor with my fingers, but the metal inner part must be corroded in because it isn't budging. I used some vice grips to try and pull on the plastic end, and I still couldn't get it out. The plastic end is starting to get a little battered now.
I put the new plastic clip on and plugged it all back together, so it's still driveable. Anyone have any suggestions? I really have no idea how I'm ever going to get that stupid thing out, and I just spend half the day laying on the engine tugging on it.

edit: "couldn't hurt to replace it" hardly describes what happened. Skinned knuckles and, it turns out, a cracked vacuum line where it attaches to the brake booster causing a stiff brake pedal. Still hoping someone will post with a good idea about how to get that temp sensor out...
 
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lucasaltic

Active member
Joined
Feb 19, 2010
Location
San Diego, CA
TDI
2000 Jetta TDI, 2006 Jetta TDI
Advance Autoparts CTS Swap

All,

I used the many good pieces of advice from this thread to replace my CTS today. I ran to Advance Autoparts to pick up a new green CTS aftermarket replacement for $9.99 (it has a lifetime warranty!). The part came with the O-ring but not the plastic clip. Luckily I didn't break the clip while removing it and everything went without a hitch. I removed the sensor plug by PUSHING the connector towards or into the sensor socket further and simultaneously pushing in on the flat plastic release tab near the top of the connector. It came out easily doing that and I didn't even have to remove or unbolt anything from above to make elbow room.

I used the "tube and water bottle funnel" method to capture the coolant as it drained out. I caught about 2 liters of fluid which I poured back into the reservoir and spilled about an ounce while fumbling with the funnel to properly place it under the sensor port. Unfortunately, my half milk-jug drain pan had tipped over initially and I lost about a liter of coolant before I got it up-righted, enough so that it put me below the minimum fill line in my reservoir.

The sensor swap took about 20 minutes total. I did notice some whiteish residue around the old sensor and O-ring and also got some on my finger when I went in after the old O-ring. Any ideas what that might be?

So those are my experiences. Hopefully they help the next guy do it a little bit faster and cleaner.

Luc

Note: The fluid comes out VERY fast once the sensor is completely pulled out of the port, so don't think you will be able to just quickly insert the new one with minimal fluid loss. You will likely loos most if not all of the fluid that can come out of that hole! You will definitely need something to catch it and it is probably best to let it all drain before trying to reinsert the new sensor.
 
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lucasaltic

Active member
Joined
Feb 19, 2010
Location
San Diego, CA
TDI
2000 Jetta TDI, 2006 Jetta TDI
Logos,

Is it possible that part of your old broken clip is still stuck in one of the slots on either side of the metal port where the sensor inserts? The fact that you can rotate it makes it sound like there is still something holding it in the port. Just a thought.

Luc
 

gabbro

Member
Joined
Dec 23, 2006
Location
Austin, TX
TDI
2003 Jetta
Switched CTS this morning on '03 Jetta. Particularly helpful: note position of CTS before removing, leave disconnecting wired connection until after new CTS inserted, largish ziplock bag easy to position to capture and re-use fluid (spilled some anyway), long small flathead screwdriver to help get clip off, hug the engine-right arm under-left over, new sensor in right hand to quickly stem flow, fish old washer out first, let old sensor hang by electric component, same small screwdriver to disconnect electric.

Helps to see a replacement clip ($1.30 @ dealer parts). New CTS (AutoZone-Duralast) and washer feels a bit loose, but guage working, and no leaking. Dielectric goo might have been good--replacement pins (4) are smaller than original. CEL still on. Consulting VAG COM ...
 
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