Model: Audi A4L 2.0T B8
Miles traveled: 149,000
Fault symptom: None (the idler wheel of the tensioner of the original car has traveled for 150,000 kilometers, and it is time to replace it)
Replacement items: generator belt, belt tensioner, idler pulley
Accessories brand:INA
Tools needed:16 open-ended wrench, 30-long M12 twelve-corner head, 30-long T40 head, and 10 ring wrenches.
Without saying much nonsense, explain while drawing pictures
Three-piece set: 340 yuan
Details of the idle wheel, everyone can distinguish between the truth and the truth
Tensioner assembly
First, put a 16-ring wrench on the tensioner, compress the spring clockwise, and release the belt
After compressing it in place, find a 4mm drill bit or pin to secure it to prevent rebound. Remove the belt at this time.
Prepare to remove the tensioner with 10 ring wrenches and 12 corner ring wrenches
The two tools combine like this
Send the screws counterclockwise, and be careful not to fall off the head, which makes it difficult to find the guard plate
Loosen the screws and use your left hand to press them sideways to unscrew the screws by hand.
After removing the tensioner, you can see the idler gear below. The idler gear screw is T40
Next, remove the idler gear, use a combination of 10 wrenches and a T40 batch head to remove it. This batch head is not easy to place. It is recommended to put a magnet on the idler gear screw first and then put the batch head on it. I dropped it on the engine guard twice. Finally, I used a magnet to put it in.
After placing the T40 batch head, remove the wrench set.
Where do you come from? Compare the size and details.
Summary of disassembly parts:
The space is small, and the person stands on the left side of the front of the car. Both the tensioner and the idler pulley mainly rely on the left hand to remove the screws. When setting the batch head, they use magnets to prevent the batch head from falling. When removing the idler gear, the 10 wrenches are not long enough. They can be lengthened with a steel pipe. Otherwise, the space between the front and the fan bracket is more than 4 centimeters, which will be difficult to use force with hands and the screws cannot be removed.
When the screws are loosened, you can use your left index finger to move the screws until they are removed.
When installing new parts, operate in reverse order. Grasp the moment of attention well,
This is when I was installing the idler gear. I removed the engine guard just to find the T40 batch head that fell off.
Next, install the tensioner and tighten the screws with your left hand. Then the tool applies force
At this time, it is time to install the belt. The new belt is bent and is difficult to set. After removing the guard plate, you can lay under the car and put the crankshaft wheel, compressor, and idler wheel. When these three are set well, you can put it on it. Set the tensioner and generator belt.
16 Wrench loosen the tensioner and remove the limit pin.
After releasing the tensioner, plug in the oil pressure sensor and start the test run.
Note: Regarding the forward and reverse of the belt. The words on the belt can be read in the forward direction!
There was no problem in the test run, but the tensioner beat at a higher frequency than the original. The reason was that the belt was packed and shipped in half. When the new belt was running, the crease had not yet been opened, so there was a beat. This is normal!
Pack up your tools, come back and study the old tensioner and idler pulley,
Turn the tensioner with your hand and feel that there is already a noise in the bearing. This is the feeling in your hand and cannot be heard by your ears.
The idle wheel was turned by hand, and there was already a slight salsa sound. This was audible, but in the car, the engine noise was drowned out.
Summary: At 150,000 kilometers, the life of the idler pulley of the generator belt tensioner is almost the same. Don’t wait for the abnormal sound to repair it, it may throw you on the road at that time.
ClarenceRoy 
3 
September 3, 2024 
