2006 Katech C6 Z06 (ser #3) 550whp
Driving to work yesterday my water pump decided to eat itself. Only issue I ever had with the engine in the 3 years i have owned it. I was on a major highway (495N in Ma) when it happened doing about 30-40mph. There was a lot of traffic and it was raining so it was a slow roll. Car started to make weird noise for about 1-2minutes and then coolant over temp warning came on. I switch the DIC to coolant temp and it was at 266F. I also noticed that the voltage output was 11.8volts which I was like WTF. It went into limp/protect mode about 10seconds later and lucky for me there was an off-ramp /exit right there so i swung off the road and parked underneath the highway I was just on. Good thing too cause the sky opened up and it was torrential downpour and lightning.
Under the hood the water pump pulley was detached from the housing and tilted, leaning against the radiator fan shroud (not hitting the blades which were still running). The pump itself was still able to rotate by had so it was not seized. Once the coolant over-temp light came on the engine only ran for a minute or so to get off the highway (almost no breakdown lane and would have been very dangerous to stop on) before I shut off the engine.

I got the car towed to my house, about 35 miles away, which cost me $280 and missed a day of work. I did order a new OEM water pump, belt tensioner and belt for $265 shipped from RA. I will be installing myself next weekend and it doesnt look like that bad of a job. When I did get the car home I started her up just to get her into my garage and engine behaved and sounded normal with no CEL's. It was a bitch to steer her up my driveway with no power steering. Visually there is no other damage that I could see. Could have been a lot worse! Pulley could have easily damaged my ATI super dampener, Dewitt Radiator or fan. Not to mention I could have cooked the engine which I fairly confident did not happen. Searching this forum, I did notice a few post about this happening to others. Weird issue!

 

I've never heard of that happening to an N/A motor, geez. Sounds like you did everything just right.
I put an electric water pump on when I did the supercharger for exactly this reason but I would have never expected it on a non boosted set up.

 

When I installed the A & A S/C I decided to go ahead and install a new water pump, (came with a 165 degree thermostat) just in case (if you know what I mean). I also went with the ECP upgraded aluminum radiator (2 rows of 1" tubing), again, just in case. We need all the cooling possible with the S/C's in the desert summer heat. You were very fortunate to not have the radiator damaged with flying parts. The water pump install is very reasonable. Take your time and torque the bolts accordingly....water pump bolts--first pass is 11 lb ft--final pass is 22 lb ft. tensioner bracket bolts for accessory belt is 37 lb ft. Good luck.....

 

The only thing I can think it could have been a factor is the tensioner I have on the car. It is a Katech one and the tension is manually set. I can be heavy handed and I could have slightly over tensioned it. I decided to go back to OEM style tensioner.

 

Easy to spot the problem, and the only time you go manual belt tensioner, is with SC to keep the belt from slipping as a band aid*. But even then, you can not over crank the tension on the belt, or you will start to case problems with other pulley, such as here.

* band-aid, since if you are over spooling a S/C in the first place that it causing the main belt to slip, need to install its own secondary belt system, so you can add tension to just that belt, not the main belt to cause problem with over tension on the other pulleys, which just end up back where you started here.

 

https://www.corvetteforum.com/forums...p-failure.html

Here is another one that had this same failure as mine. Same Katech manual tensioner. For the record, the manual tensioner came with the car when I purchased it. Torque on the tensioner (for the belt tension) is set at 20 ft-lbs per intructions. It is real hard to hold the torque wrench exactly at 20ft-lbs with one hand and tighten the stop bolt down with the other. Could be anywhere between 15-25 ft-lbs when done. Happy i'm going with stock GM tensionier.

 

Problem is, you have to treat the belt system like its a Harley primary chain system, with none of the pulleys running true concentric in the first place., So would need to rotate the belt until you do find the tight spot across all the pulleys under higher rpms, then that would be the point that you could adjust the manual tensioner to it torque settting.



But since not running a S/C in the first place, then forgo the manual tensioner and just install the spring loaded unit, that will adjust with how the pulleys are not running concentric in the first place, to keep a constant tension to the belt at all times instead.

 

I seem to recall a few people having this problem when running a manual tensioner.

 

Yup. When the belt stretches under load, and it always does, you lose tension and get belt slip. To try to "cure" that, you run way too much tension. That's where all the drama comes from. Those were a bad idea from the get go. Heavy duty spring loaded tensioner and/or more ribs is a better solution.

 

Just wanted to post an update. Literally took about a half an hour (not including draining the coolant) to swap out the water pump. Super easy install! I went with OEM GM water pump, tensioner and belt. Total cost was $265 parts plus $30 coolant. Bleeding the sytem now usung the funnel method and everything iis running great,