How To Replace A Fan Belt Sensor

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  • Difficulty: Moderate
  • Avg. Time Necessary: 1-2 Hours
  • Cost: ~ $100


The bearing inside the fan belt roller sensor can become dry and rusty over time and starts to squeak. It usually starts to make the squeaking noise only in the morning but eventually the problem will get worse and the squeak will remain constant. I believe moisture plays a big part on the cause of this problem, and when the bearing gets dry it will starts to squeak. Most often the squeaking noise has been blamed on the belt, but the roller is also one place to check for the source of the noise.

Note: The fan belt roller in the part catalog is called "sender", since the only function of the roller is to send a signal to the DME telling it that the fan belt is functioning properly. On all 993s prior to 1997 the fan belt roller part number is 964 106 035 07, after 1997 an updated roller part number 993 106 035 00 was introduced.

Tools required for this DIY are:

5 mm allen socket


Lubrication oil

There is only one 5 mm allen bolt that holds the fan belt roller in place. To remove the 5 mm bolt I strongly recommend using a 5 mm allen socket to remove this bolt. Because of the limited space you have to work with you will be tempted to use an allen key, but I strongly suggest against this idea.

Image:993 fan roller - rollerb.jpg

Prior to the removal of the fan belt roller I had to make a slight modification to my 5 mm allen socket in order for the tool to fit in the confined space. As you can see from the picture the allen shaft on the allen socket is quit long. I had to cut a section of it off in order for it fit into the engine bay with the ratchet attached.

Image:993 fan roller -5mmbeforeb.jpg

Image:993 fan roller - 5mmafterb.jpg

Be very careful once the bolt has been loosen to take the bolt off first before you remove the fan belt roller. Because if you are not careful and bolt will fall off and you will have one heck of time to fish it out from under the crank pulley.

Image:993 fan roller - removeb.jpg

In my case I used some "Break Free" lubricating oil to soak the roller bearing assembly with oil. "Break Free" oil can be picked up from many firearm shops, it is primary used to provide lubrication and protection to firearms. I poured some oil in the bearing area and had it soak over night before installing the roller unit back on to the car.

Image:993 fan roller - breakfreeb.jpg

Image:993 fan roller - oilsoakb.jpg

Reinstall the fan belt roller and you are done. The squeaking noise will not come back for sometime.

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All auto modifications and repairs listed at are to be done at your risk. does not, at any point, assume responsibility of any injury, damage, or charges that may occur through modifying or repair of your or anyone else's car. Car modifications are to be done at your discretion and should be done by qualified individuals. Please check your motor vehicle regulations regarding any car modifications or car tuning you may do to ensure they are street legal.