P0128 diagnosis with torque or vcds?

So i got a cel today. Cleared it and hasn't come back in about 30 miles. Im assuming that since my temp gauge sticks at 190 at normal running temp like it usually does i can rule out a sticky thermostat. No under or over heating. For no egr the heat does well on cool spring mornings.

Is the reading i get from vcds or torque pro the ecu side of the coolant sensor or the gauge side? I want to know If i should be looking for a difference in temps

Should the thermostat be a 160 or a 190? I'll run the scan tool on my commute this morning.

If i knew what ohms both sides of the rear block temp sensor should read i could easily diagnose that as well.

I have g12 in her now with non tap water. As far as i know the po also only did g12. It was pink and the block was clean for 200+k on the water pump change.

I always install thermostats and CTSs together. The CTS is such a common failure item, and they are so cheap, it makes no sense to play games with it. Unfortunately on the BHW, the CTS location is a bit more challenging than on the transverse cars. Thermostat is easy. I would only use a Behr or Calorstat thermostat (or OEM), with a new OEM water flange and o-ring.

We have had good success with Eth branded CTS.

Your cars normal operating temperature should be 190F. That is also the temperature rating of the thermostat you should have installed. However the gauge is only approximate as quicktd pointed out. My temperature gauge reaches the straight up 190 mark when my engine is actually only at 164F as verified by my ultragauge. I have seen my temperature go as high as 213F and the needle remains at 190.

As far as coolant , pink is good that sounds like what is supposed to be in there. Don’t mix vw pink with green anything or even all purpose yellow unless you want collateral system problems.

I've been driving nearly an hour and not hit 170. My gauge also hits 190 on the dash around 164 deg via torque pro verification.

Looks like a sticky thermostat

Ive got the cts on order (even if mine is good ill replace it for good measure) and I'll see if i can get a brand name thermostat/associated parts in at the same time. What's a pita is no one on this side of town carries g12 only g40. I have to order it. I also have cv axles that look new but rattle like penny's in a jar to replace. A passat is a lot like a boat. .never really done!

So i guess ill try to get a clean jug to recycle my coolant since its got less than 1000 miles on her.

After an hour without hitting 170, yup your thermostat is stuck open. Which is better than stuck closed. Get an oem thermostat don't go cheap or you'll have the same problem again..soon.

Idparts has oem thermostats and gkn axles. Or you can rebuild whichever cv joint is giving you problems.

I don't have anyone that carries quality vw parts locally. I barely have a town, what alone one with two sides. At any rate it sounds like you would be able to hold out till parts arrive.

I just purchased an 03 wagon v6 5speed just for the oem axles. Raxles is about to get a call once pulled.

NAPA and Autozone has Pentosin coolant but very expensive. VW sells it for $25/gallon. In the big scheme of things not that pricey

Get the OEM T-Stat. Again, VW sells it for about $35

I got a behr thermostat and oem flange on order along with another oem vw jug of coolant incase mine spills or gets contaminated while draining.

No telling how long this thing has been sticking. Wish i had known it was going before i put the car back together. Same should be said about the new looking cv alxes i tossed in that came with the donor car.

I was wondering why my mpg kept hoovering around 35 mpg, i would have assumed id get closer to 40.

The vw coolant is cheaper than my commercial cost on the pentosin. Its fee shipping so that saves me a trip to vw. Im not sure if there is a vw dealer in Easley but i don't make the drive towards Laurens rd unless it's to play hockey.