WHOOPS! Major Error in fixing Cooling sensor

Car: 2012 GTI

I've had several cooling errors recently that I tried troubleshooting on Sunday and now I'm kind of lost. My engine temp gauge has been finicky lately and sometimes read as zero even though the engine had been on for a while. Additionally, I had a low coolant light come on and rightfully so, my coolant level as below the min line.

So on Sunday, I filled it up with the G12/13 fluid at 50/50 mix, but after filling and running for a while, my engine temp gauge still read as zero. So after searching online and finding several places (like this) that said it was likely the engine temp sensor, i went out and bought one at autozone.

This is where I screwed up. I could not find the engine temp sensor for a 2012 anywhere online/videos and so I did my best guess based on the intel that there is a clip along the coolant system and that's where it was. See attached photo... this is in the front/right part of the engine near the engine fan.

When I removed the clip (and after venting the coolant storage for vacuum), I'm pretty sure all of my coolant came pouring out on my driveway. And low and behold, this was NOT the engine temp sensor area as there was a spring inside and this piece of metal/o-ring (ride side of pic) that I saw fall down to my skid plate. (The replacement engine temp sensor is on the left)

I have no idea what this component is and which way it's supposed to go in. I've tried looking at diagrams and searching part places with no luck. I also tried finding a Chilton online/at autozone for my car with no luck.

So the car is sitting unused in my garage because I don't know what I'm supposed to do to put this together and get this fixed. And help would be appreciated! If you are local to Dallas/Fort Worth, I wouldn't mind pitching in some bucks/beer if you know exactly what to do and will come help.

DFWTCU said:

Car: 2012 GTI

I've had several cooling errors recently that I tried troubleshooting on Sunday and now I'm kind of lost. My engine temp gauge has been finicky lately and sometimes read as zero even though the engine had been on for a while. Additionally, I had a low coolant light come on and rightfully so, my coolant level as below the min line.

So on Sunday, I filled it up with the G12/13 fluid at 50/50 mix, but after filling and running for a while, my engine temp gauge still read as zero. So after searching online and finding several places (like this) that said it was likely the engine temp sensor, i went out and bought one at autozone.

This is where I screwed up. I could not find the engine temp sensor for a 2012 anywhere online/videos and so I did my best guess based on the intel that there is a clip along the coolant system and that's where it was. See attached photo... this is in the front/right part of the engine near the engine fan. View attachment 54704

When I removed the clip (and after venting the coolant storage for vacuum), I'm pretty sure all of my coolant came pouring out on my driveway. And low and behold, this was NOT the engine temp sensor area as there was a spring inside and this piece of metal/o-ring (ride side of pic) that I saw fall down to my skid plate. (The replacement engine temp sensor is on the left) View attachment 54705

I have no idea what this component is and which way it's supposed to go in. I've tried looking at diagrams and searching part places with no luck. I also tried finding a Chilton online/at autozone for my car with no luck.

So the car is sitting unused in my garage because I don't know what I'm supposed to do to put this together and get this fixed. And help would be appreciated! If you are local to Dallas/Fort Worth, I wouldn't mind pitching in some bucks/beer if you know exactly what to do and will come help.

Click to expand...

Isn't that where the harness plugs in? Every VW temp sensor gauge has you quickly swap over the new plug to prevent fluid from pouring out. Pretty typical for this repair.

Nice DIY here http://www.pelicanparts.com/techart...R-Coolant_Temperature_Sensors_Replacement.htm


This is for another engine, but demonstrates the repair. I'm not sure where you're getting a spring from though.

We'll I put whatever that piece was back in, refilled the coolant, and replaced the engine temp sensor, so now I'm getting a good temp reading on my dashboard.

But now my heater is only blowing cold air, even with the heater on full blast. Any new ideas what may be happening?

You have air in your cooling system. I don't know how to bleed that out. Hopefully someone who does will chime in here.

1ashchuckton said:

You have air in your cooling system. I don't know how to bleed that out. Hopefully someone who does will chime in here.

Click to expand...

Pretty sure its a non burping system.. at least i think i read that somewhere that's why when they change it they hook it up to a machine to keep it pumping through so it doesnt get any air spots


But im not exactly sure.

Interesting but the problem remains the OP has air in his cooling system. He might try driving with the reservoir cap loose. That may let that trapped air escape. Just a guess on my part.