Couple quick questions

sundevil36

Well-known member
Joined
Oct 27, 2015
Location
Santa Barbara
TDI
2002 Jetta TDI
I am planning on replacing the coolant temp sensor, the manual says the car hols 6 liters of coolant total, will a majority of that drain out in the replacement process? Will a gallon of G12 (3 and change liters) refill it or should I get more or less? I've seen people reuse the coolant if its caught in a pan, but that makes me nervous as any dirt or gunk caught up in the liquid on the way to the pan could be problematic, right?

Second, my ASV wiring is frayed due to the known corrugated tubing rubbing issue, can I splice/solder any ol' 20 gauge wire to the existing harness? And once that is fixed, is there anything that can be put on the outside of those wires to prevent further fraying?

Thank you all for the help, I've fixed several issues with all of your guidance and knowledge!
 

Rembrant

Veteran Member
Joined
Oct 31, 2014
Location
Canada's Ocean Playground
TDI
2013 Golf TDI DSG
Second, my ASV wiring is frayed due to the known corrugated tubing rubbing issue, can I splice/solder any ol' 20 gauge wire to the existing harness? And once that is fixed, is there anything that can be put on the outside of those wires to prevent further fraying?
I've had to repair these wires on my current 03 Golf, and the 03 Jetta before it. I soldered in new wires...and used heat-shrink to cover them. I then put new wire loom back on...same as the original corrugated tubing stuff. I put 2-3 cable ties on over the wire loom to keep it from chafing the wires again.

Rem
 

Chazhill14

Well-known member
Joined
Apr 23, 2012
Location
Greenville, SC
TDI
2003 Jetta TDI, 1975 F100 5.9 Cummins
Any automotive wiring should work assuming it is the correct size gauge. If you are worried about it fraying further, why not reroute it or as Rembrant said, put new wire loom around it.

I've never changed the coolant temperature sender before but I have pulled my engine several times so I can tell you that I've only ever used at most a little more than a gallon of full concentrate and a gallon of water when refilling my engine after getting it back in the car because the block will retain a lot of it. For your sake though, I would get a gallon of concentrate G12, mix it and keep whatever you don't use just in case. It's not like you have to feed it or anything.

EDIT: For some reason I was thinking you were talking about the thermostat, I have no idea why. The temperature sender will probably release very little water as it is high in comparison to where most the water sits in the engine/coolant system. So you would not need much coolant at all to replace whatever comes out.
 
Last edited:

steve6

Veteran Member
Joined
May 25, 2010
Location
Beaverton, ON
TDI
2003 jetta tdi
I am planning on replacing the coolant temp sensor, the manual says the car hols 6 liters of coolant total, will a majority of that drain out in the replacement process? Will a gallon of G12 (3 and change liters) refill it or should I get more or less? I've seen people reuse the coolant if its caught in a pan, but that makes me nervous as any dirt or gunk caught up in the liquid on the way to the pan could be problematic, right?
If you are prepared, have the new one handy, you can change this real quick and loose minimal fluid. I would just put fresh fluid in, you will have enough with a gallon, remember you have to mix it 50/50 as well, it will give you 7 + litres after being mixed.
 

sundevil36

Well-known member
Joined
Oct 27, 2015
Location
Santa Barbara
TDI
2002 Jetta TDI
If you are prepared, have the new one handy, you can change this real quick and loose minimal fluid. I would just put fresh fluid in, you will have enough with a gallon, remember you have to mix it 50/50 as well, it will give you 7 + litres after being mixed.
thanks, forgot to look if it was 50/50 or not, that'll make a big difference on the order. I really should get a multimeter tool to check things but I haven't yet.
 

94cobra2615

Veteran Member
Joined
Jun 16, 2013
Location
ohio
TDI
2002 Black Wagon
You can also drain the coolant system with the handy drain valve on the driver side lower part of the radiator. Give it a quarter turn and it will drain away.

Use a nice clean drain pan and reuse the coolant. This will minimize your coolant loss.
 

JB05

Top Post Dawg
Joined
Oct 20, 2005
Location
Il.USA
TDI
Golf,2005,anthracite blue
Plastic sheathing for wires is available at most auto part stores. It's kind of tricky to install, but should work. Allow yourself alot of room when removing the CTS; remove any air intake hoses that may be in the way. You don't have to remove the wire harness until the new sensor is installed. Leave it attached to the old sensor and just let it hang. It won't go anywhere.
 

gforce1108

Top Post Dawg
Joined
Aug 2, 2006
Location
Newburgh, NY
TDI
04 Jetta GLS BEW, 14 Audi A7 V6 TDI, 13 Porsche Cayenne V6 TDI
You can also drain the coolant system with the handy drain valve on the driver side lower part of the radiator. Give it a quarter turn and it will drain away.

Use a nice clean drain pan and reuse the coolant. This will minimize your coolant loss.
I agree - I tend to find it easier to drain it than to clean up what leaks out. This also lets you know if you have air pockets somewhere - if you put in what came out, you are all set.

I change the fluid during a timing belt, otherwise it gets reused.
 

sundevil36

Well-known member
Joined
Oct 27, 2015
Location
Santa Barbara
TDI
2002 Jetta TDI
You don't have to remove the wire harness until the new sensor is installed. Leave it attached to the old sensor and just let it hang. It won't go anywhere.
I had read that somewhere, no reason to pull the sensor out unattached to the wire, as it also protects the connector. Sounds like I should drain and reuse as that provides marginally more diagnostic information. I'm going to look into the wiring as well, sheath or heat shrink shouldn't be too hard to find.
 

PGM jetta

Veteran Member
Joined
Dec 14, 2015
Location
Northern Alabama
TDI
05 Jetta BEW
You don't have to remove the wire harness until the new sensor is installed. Leave it attached to the old sensor and just let it hang. It won't go anywhere.
I do the exact opposite. Unplug the harness first and plug it to the new sensor, then remove the old sensor and put in the new one. That way if you somehow drop it trying to install, it just dangles instead of falling into the abyss
 

sundevil36

Well-known member
Joined
Oct 27, 2015
Location
Santa Barbara
TDI
2002 Jetta TDI
Update with another question, I've been crazy busy so I haven't been able to complete these repairs yet. In the last couple of days though, the CEL has turned it self off twice and come back after about 50 miles and several starts. Is there any reason for this? Two issues just aren't detected and then they are?
 

sundevil36

Well-known member
Joined
Oct 27, 2015
Location
Santa Barbara
TDI
2002 Jetta TDI
Ok, so I finally had an hour to poke around with VCDS. It's now coming up with:

Address 01: Engine Labels: 038-906-012-AGR.lbl
Part No: 038 906 012 FD
Component: 1,9l R4 EDC G000AG 4102
Coding: 00001
Shop #: WSC 00066
VCID: 57B384A8B5923E8660

1 Fault Found:
16512 - Coolant Thermostat Valve (N214)
P0128 - 35-10 - Temperature below Control Range - Intermittent
Readiness: 0 1 0 0 0

That is different than the previous codes, I believe I fixed them just enough to not throw a code. I replaced the CTS and spliced in a new wire to the ASV, so those codes have not come back as far as I know. What's next? Replace the thermostat? Really hoping not...
 

underwhelmd

Veteran Member
Joined
Dec 18, 2015
Location
Canada
TDI
1998 Beetle
What's next? Replace the thermostat? Really hoping not...


It's really not that bad! You're going to need a lot of coolant again. There are some good DIYs with pics showing the process that you will find with a google search. Take heed when they say: protect the alternator from the rush of coolant when you remove the thermostat.
 

sundevil36

Well-known member
Joined
Oct 27, 2015
Location
Santa Barbara
TDI
2002 Jetta TDI
I cleared the DTC just to see if and when it came back. I'm closing in on 100 miles since the code was cleared and it hasn't come back. Sometimes it warms right up but other times it won't get to the 190 hash even after a 12 mile drive to my work after mixing city and freeway driving.
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
It's likely that both sides of the CTS are failing: one side supplies info for the dash gauge, the other to the ECU functions.

Here's how I replaced my CTS (wife's car) with little coolant loss:

1. Removed the air filter housing (gets you lots of room);
2. Loosened up the coolant reservoir tank cap and squeezed the upper radiator hose while then tightening up the reservoir cap (idea is to create vacuum in the coolant system to help hold back some of the coolant when removing the CTS);
3. Put down some old towel under the CTS area to soak up any coolant;
4. Pull the clip on the existing CTS and as you remove the CTS be ready with the new one to put the new one in) BE MINDFUL that the O-ring on the old CTS MAY end up staying stuck inside the housing- if it's not on the old CTS when you pull the old CTS then immediately push the old CTS back in OR use a pick to fetch out the old O-ring;
5. Put the new CTS in (in parallel with doing step #4) making sure it has the new O-ring installed (lube the O-ring, use some antifreeze);
6. Insert the new (or old, if you didn't lose it and if you got a new one) retainer clip;
7. Disconnect the wire harness from the old CTS and connect up to the newly installed CTS;
8. Reinstall the air cleaner box.

Might have taken me a total of 15 minutes, which includes removal and reinstall of air cleaner box and toping off the coolant.
 

sundevil36

Well-known member
Joined
Oct 27, 2015
Location
Santa Barbara
TDI
2002 Jetta TDI
I replaced the CTS and so far that previous code has not come back. This is a screenshot of the vcds temp readings while the car was on. Are these numbers close at all?

 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
88 Celsius is good. (not sure why the two values)
 
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