I have the blue, the photo plus the orange simulating of dirt was an example.
I had problem in the past with one with yellow collar and the stupid mechanic that install it was trying to persuade me that is the proper one but i insisted, NO.
So i bought a new with blue ring and expensive and now i am reassured.
My service notes helped me to understand the problem, i can call it as ''sneaky" because no one could believe that was the main cause of trouble, was hiding so well.
The problem began when i change the water pump (seal leak, almost all the coolant out in the street i was luck that i found quickly a parking space and i stopped the car), something went wrong to the repair shop with the Antifreeze and then the ''downfall" came (thermostat problem, radiator switch change, 2 brand of G11 mixed with MoCool, ECU-chip needed update etc) plus the wrong valve gap and the spark plug reference.
The Lambda sensor change was not necessary but i think the MAP change was.
I spend hours, day or night trying to understand every time what was wrong and the scanning tools never helped me, deep inside me i believed that my notes and methodical work plus discipline will pay off.
This was the main reason that i bought the TC-6, it was very expensive but with this i was able to have data to rely on and not just speculations, step after step i was making progress and with your help here i can see the light at the end of the tunnel.