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Discussion Starter · #1 ·
Ok - So I finially found the determination to replace the Coolant Temp sensor.
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Simple enough but getting to the darn thing on an 03 1.8T is not easy.
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I removed the pressure pipe and combination valve along with a wire harness
and just did get enough access.
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The plastic retainer clip had been install so that the removing direction was toward the engine itself - further eliminating space to remove it.
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The KEY here: I had read in other post that the plastic spring clip could easly "SPRING OUT" on removal and be lost forever. SO I TIED A LONG PIECE OF DENTAL FLOSS to the clip prior to removal. Yes - it flew out but was retained by the dental floss teather. I would recomended highly.
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I reinstalled the clip in the opposite direction & it cliped in secure.
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However - I did find somthing disturbing. *** NEED YOUR HELP ****
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When I inspected the conbination check valve if was full of yellow brown cream stuff - oily cream. This also seems to be somwhat in the pressure pipe. I am heading to the dealer tomorrow to get a new combination valve.
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Has anyone found this before - It can't be good.
 

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Discussion Starter · #2 ·
New Combination Valve & Temp Sensor

In reply to my own post here:

I completely removed the high pressure metal pipe leading to the COMBI Valve and it was full of sludge. Cleaned it out and installed NEW COMBI VALVE.
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Dealer said that the COMBI valve fails and lets hot exhaust air gasses mix with water vapor - creating the funky stuff. Not to mention what ever the heck the valve is supose to do anyway - it was dead.
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So now everything is back together - Temp Gauge working @ 190 and I guess
the new COMBI VALVE is doing its job.
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03 1.8t Chip, TT DV - 74K
 

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Any chance of a few pics? My temp gauge works for a while then stops again then works again...
What is this combi valve you are on about?

Thanks,
Martin
 

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In reply to my own post here:

I completely removed the high pressure metal pipe leading to the COMBI Valve and it was full of sludge. Cleaned it out and installed NEW COMBI VALVE.
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Dealer said that the COMBI valve fails and lets hot exhaust air gasses mix with water vapor - creating the funky stuff. Not to mention what ever the heck the valve is supose to do anyway - it was dead.
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So now everything is back together - Temp Gauge working @ 190 and I guess
the new COMBI VALVE is doing its job.
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03 1.8t Chip, TT DV - 74K
My Combi Valve "rattles" on cold start, and when blipping throttle...gonna replace it shortly!
 

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Discussion Starter · #5 ·
Location

In the back of the engine - at the firewall - a black round top & plastic valve
is just above the coolant temp sensor. My understanding is that on a cold start - it allows warm air pass until the spring in the combi valve closes at a defined temp.
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I would highly suggest ALL Passat owners to check this valve for sludge crap that I had.
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If your water temp gauge is working only part time - the temp sensor replacement is easy once you gain access.
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Green Temp Sensor - $22
Combi Valve - $36
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*Dealer said both are very common failures.
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Expect to spend about 3 hrs to replace both - if you don't know what you are doing ` like me.
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By the Way - Bentley Manual wan NOT much help ~ sorry no photos.
 

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Discussion Starter · #7 ·
I was trying to replace the Coolant Temp Sensor and found that removing the pressure pipe and the Combination Valve - I had good access. Once I removed the Combi Valve - I noticed all the sludge inside.
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Just discovered by accident.
 
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