My car ('03 C4) started making a little noise today after an autocross event. It definitely sounded like a dragging bearing, pulley-type issue.

My wife drove the C4 and I followed. After several miles, I saw a piece of belt come out from under the car and had her immediately pull over. About half the width of the belt was gone, and I now had a coolant leak that I didn't have 15 minutes earlier.

Water pump, right? Any thing else it could even be?

(car is still parked in the same spot, by the way.... I have to go get it tomorrow.)

 

Like I told the guy who replaced his water pump without diagnosing it, get a pressure tester, pressure up your system and search for leaks, find out exactly where your leak is coming from and replace the part you actually need to. Chances are if you were hearing a bearing noise and the serpentine belt snapped it is a problem with the water pump but better to be sure than start replacing stuff you dont need

 

Good advice, thanks.

 

Same thing happened to me, it was the water pump.

 

Belt half part(s) may have pulled a hose when it came loose. Get it home (flat bed, drive it), pull the rest of the belt and check each rotating device for play, noise, freedom of movement, etc. If one of the idlers, pumps, alternator are bad enough to cut/throw the belt you will feel/hear it.

 

I too had the same issue and it was the water pump. Despite what some have asserted, some water pumps can fail without any play in the shaft or any noise. Mine had none. The seal went and that was it.

BTW, keep in mind that the belts are directional once they are installed and can fail if they are removed and replaced in the wrong direction. Porsche explicitly says to mark the belt direction if it is too be removed and replaced.

 

Good info on the directionality of the belt.

Car is on the hoist. Water pump is definitely toast. The pulley had so much wobble that I guarantee that's what shredded the belt. New pump is on the way.

While it's up in the air, it's getting an oil change, a new magnetic drain plug, 6 new plugs and 6 new coil packs.

 

You heard bearing noise the belt ripped in half and the shredded parts flew out of the car and you couldn't feel any play/roughness in any pulleys? Wow!

 

No play, no roughness. Everything was in alignment. It may be that the belt gave way per the Porsche TSB regarding the belt and ate the seal on the pump. The noise I heard was probably the edge of the belt giving way, not the bearings.

 

How old was the belt ?

 

Actually, if it's an '03 and has the original pump, there's a strong argument to just replace it anyway to minimize the chance of plastic impeller pieces from getting into the cooling channels and causing big damage.

It's not that expensive to do....and the amount you spend is a tiny fraction of what's involved if the pump goes south.

Treat it as a scheduled replacement wear item. No big deal.

 

I'm actually replacing mine this weekend as I have to change out the AOS and figured while I'm in there I might as well...

I'll start another thread when done outlining my experiences on how difficult it might be.

 

It makes sense to do the AOS and pump and the same time. Consider the coolant tank as well as it will save labor in the long run.

 

I did the coolant tank last weekend thinking that was source of my leak but it was the AOS. So I'll be repeating the steps again to remove it for this repair.

That's why I figured with nearly all the coolant out I might as well do the water pump too.

 

Can you give a link as to where Porsche state that if the belt is removed and replaced it has to go back on in the same direction or it will shred up or snap. I kind of find that hard to believe but worth noting anyway. Porsche may have meant the direction around the pulleys.