I got a check engine light for both my o2 Sensors on the passenger side. So I bought them and then went to go look to where they connect and I find that the outter most edge of my accessory belt is completely ripped off and resting in the engine bay, the o2 sensors have been rubbing against the spinning pulley and have worn through. Looking down by where the water pump pulley is I can see a small metal bracket that looks bent out of place, but I am unsure if thats the culprit or not.

Either way,

I plan on doing a new belt, new o2 sensors and potentially engine mounts.

Anything else I should look at?

 

Make sure there is no knicks on any of the pulleys that could have potentially caused the cut belt. If there’s the slightest Knick on the ribs it will eventually cut through the belt.

 

It was the leading edge of the belt that got torn away. I will be talking to a dropping it off at a shop this week for the repairs. I will go over with them how important it is to scan each pulley and replace any idler pulleys with even the slightest of resistance.

Anyone suggest going with a lighter crank pulley from the gt3RS?

 

My experience with my Boxster -- my Turbo never manifested this -- was signs of wear on the edge of the serpentine belt -- the edge was "sharp" compared to the other edge which was "dull" -- arose from a water pump with bearing play. The bearing play was not severe either. Only after I have removed the belt and checked each accessory drive for play did the water pump stand out as the accessory drive under suspicion as it had a bit of play while the other accessory drives had no play.

But there was sufficient play to let the edge of the belt rub against the pulley's side and wear the edge sharp.

I was clued in there might be a problem because of some noise that I confirmed was coming from the accessory drive system. (I removed the belt and started/ran the engine just long enough to confirm the noise was not present thus it was accessory drive related.)

What my 2003 Turbo manifested -- twice -- was what proved to be a bad idler roller bearing. The first time the symptom was with the engine idling a "dry bearing" sound. The 2nd time an intermittent "chirp". The 1st time the car was under CPO warranty and given I had never had any problems the idler/tensioner bearings in my Boxster (these were original even at 317K miles) I had the tech replace all idler rollers and even the tensioner. The 2nd time a roller bearing acted up I had him replace all again.

To be clear you must someone must confirm there is nothing out of place that the belt can rub against. Next the accessory drives need to be checked for any signs of bearing play. The water pump on my Turbo failed but the sign it was bad was coolant leak sign at the water pump. I don't know if the water pump had developed any play.

If an accessory drive is found with bearing play this must be addressed.

At the same time the idler and tensioner rollers need to be checked for any signs of bearing issues. This might be in the form of excessive play, too much (or too little) spin resistance, signs of seal degradation. You will have all the bearings to check and the one -- odds are it is just one -- that differs from the others is the bad one. Or you can just replace them all.

 

I am dropping it at the shop tomorrow.

I had the shop order the belt to begin with and then he is going to check the idler pulleys after its all apart. I expect to have to replace 1 or both idler pulleys. I have no coolant leaks whatsoever so I hope its not a water pump. I guess those are not cheap for this car??

I probably just jinxed myself! Ill keep you all posted!

 

The water pump is cheap and pretty easy to replace.

 

With my 2003 the water pump was partially blocked by some frame cross member or some body structural brace. The tech may have lowered the engine a bit to make getting the old pump off and the new pump installed. He had some kind of engine support that bolted to the place the rear sway bar bolted to -- the rear sway bar had to be removed first -- and had a bolt with a flat pad to use to adjust the engine up or down a bit.

I have pics of the Turbo water pump but I didn't get any pics of it in place.

 

The easy way is to... Put a jack under the engine and remove the engine mount at the rear side of the engine (5 minutes). After that, there is very little in the way and it is a quick fix. Not necessary to remove the sway bar.

 

Here is a link to a DIY I made up to replace the water pump... Water Pump Replacement DIY

 

So it was just the belt. Still unknown as to what caused it. There was a metal clip that was extending a little far into the belt path where some engine movement may have allowed the belt to get clipped or caught up causing it to shred itself. Idler rollers were fine. I do have a power steering fluid leak coming from the pump. So I will be getting that replaced in a few weeks.

Either way, the car is getting new rear tires early next week and then an alignment and it will be back on the road.

Now to fix my B8 S4 DSG transmission. God Damn audi sux at making dual clutch transmissions.