Golf 4 Temperature Gauge Not Working: Troubleshooting

A colleague just approached me. On his 2003 Golf 1.6, the temperature gauge in the instrument cluster isn't working. Initially, it would occasionally fail for short periods, and the needle would sometimes drop to the "cold" mark on the left. For the past few days, nothing has happened at all; the needle is stuck. The engine runs smoothly, and fuel consumption is normal.

Where should I start looking?

Hello,

If the issue relates to the coolant temperature, the sensor located on the engine is a common source of problems.

Best regards, Rainer.

Okay, I mean the coolant temperature indicator! Can you tell me where I can find it on the engine? Unfortunately, I don't have much experience with VWs and therefore lack any basic knowledge.

What kind of 1.6 engine? Is it an SR, 16V, or 8V? Does it have 101 hp, 102 hp, or 105 hp?

At the water outlet nozzle.

So, it's inserted towards the front, from the direction of the transmission or from above, and secured with a clip.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

1.6 16V. I don't have the documents available at the moment. My colleague is in class. I will take a look at it when he has time.

PM with pictures.

Okay, thanks! But I'm not allowed to download it at work, so I have to wait until tomorrow...

I found the thing! It's actually located above the clutch bell. However, it's not accessible because of the dining table that's installed on the engine . By the way, it says "1.6 SR" on it.

Hutfahrer wrote:

..."1.6 SR" is actually printed on it.

Then it's not a 16V engine; the SR models are the 8V engines with 101 horsepower.

My colleague told me about it. I was only able to take a look under the hood just now. How does an eight-valve engine with only 1.6 liters manage to produce a reliable 101 horsepower?

101 horsepower / 1.6 liters = 63.1 horsepower per liter.

That's not an achievement to just get it to be durable.

The 1.6-liter engine in the Golf 2 had approximately 25% less power. The specific output of the comparable 1.8-liter engine from the Golf 3 or Passat was even lower.

Hutfahrer wrote:

The 1.6-liter engine in the Golf 2 had approximately 25% less power. The specific output of the comparable 1.8-liter engine from the Golf 3 or Passat was even lower.

However, time doesn't stand still either. One fact remains: 63.1 horsepower per liter isn't *that* outstanding a power-to-liter ratio.

Feedback: The connector on the temperature sensor is corroding. The contact pins are heavily damaged. Unfortunately, the connector on the wiring harness is also affected.

My colleague was able to carefully disassemble it and cleaned the contact pins on the sensor as much as possible with a fiber optic brush. However, he couldn't reach inside the connector itself. He initially reassembled it using plenty of lubricant, and now the display is working normally again.

In the medium term, it might be possible to replace the sensor. I think you should also replace the connector at the same time. However, nobody seems to have a single one lying around here. Soldering and securing it with heat shrink tubing shouldn't be a problem for me.


Since there are no MKL (presumably a type of sensor) readings visible, it seems this sensor is only responsible for the display in the AI (likely referring to an artificial intelligence system). Is that correct? If so, I would only address this issue if the problem becomes acute again.

Hutfahrer wrote:

Since there are no MKL (presumably a specific component) visible, it seems this sensor is only responsible for the display in the AI (Artificial Intelligence) system.

Is that correct?
Yep, that part is called a "dual temperature sensor" for a reason. It has 4 pins and communicates with two NTC sensors.

You can buy the plugs individually; they should cost around 3-4€. I can bring some pins for crimping to our meeting if you want.