PPD 1.2 Temperature Display Problem

Hello everyone.

Recently, I've been having a problem where my engine barely reaches 90°C.
Sure, here's the translation:

"Preliminary information:"
My car has been chipped by me since August 2013.
It's my hobby.
I drive the car 160 km every day to work, and it's all highway.
I have never had any problems with the engine warming up; in fact, according to my VCDS logs, it warms up perfectly.
My DPF reaches temperatures of up to 850°C under full load, while the engine temperature fluctuates between 82-88°C.
Sometimes, under full load, it reaches 92°C.

I replaced the oil cooler because I had oil in the coolant reservoir. It was a lengthy process, but everything is working properly now.
Yes, it's possible that my head gasket is also damaged, because when I open the reservoir with the engine warm (but turned off), the level rises, which suggests that air is getting in.
Perhaps someone can give me a little advice on this. I've always driven with the minimum amount of oil in this car, but now the oil level is slightly above the "middle" mark on the dipstick.

After 20-25 minutes of being stuck in traffic, I reach 85°C. However, 10 minutes after I start moving again, the temperature drops to as low as 55°C (outside temperature is approximately 10°C).
Last winter, I didn't have this problem, which is incredible.

I'll be logging data with VCDS this weekend. Can anyone suggest other parameters I should log?

Please help!

Thank you very much in advance!

Hi.
When does your thermostat valve open?
It's not that it doesn't close properly and the cooling always goes through the radiator.
Best regards, Frank.

Hello, thank you.

Can you tell me what I should log?

I'm also checking to see if VCDS throws out any error codes.

Today, the temperature at work was again 60°C according to the display.

I would also like to mention that I had a check-up, as I do every year, and since then I've been experiencing this problem.

Could it be possible that the motor oil, which previously entered the cooling system, is slightly clogging or causing sludge buildup on the valve?

Quote:

After 20-25 minutes in traffic, I reach my 85°C, but once I start moving again, 10 minutes later, the temperature drops to as low as 55°C

.

Here, you've already indirectly mentioned the cause.

The thermostat is no longer closing completely, which causes the engine to cool down too much when there's airflow.

In the case of a faulty thermostat (open circuit), the engine and radiator should warm up simultaneously.

Hello, thank you.

Unfortunately, I don't know exactly where the thermostat is located; I haven't found anything directly on the radiator.
Could it be located on the engine block, above the transmission?

Best regards

It looks like a Golf or a Touran, so it's probably a BMN model.

It should be placed between the climate compressor and the block.

I don't have the exact list of everything that needs to be dismantled right now.

Quote:

...My car has been chipped by me personally since August 2013. is my hobby...

What tools do you use to process and program the datasets?