a/c serpentine belt and Water pump mystery

[Nobleprofessor]

I was driving this weekend on a long trip (4 hours) and my ac working fine. In fact, my son and wife were complaining it was too cold. We stopped for gas and when we got back in the car, the a/c was not working -- at all. I drove for a little while and didn't understand how it could work perfectly and then suddenly stop. I stopped in a small town and decided to check some fuses to see if maybe a fuse was bad. I couldn't find any problems. I bought a can of 134 with the gauge thinking maybe it was low. When I put the gauge on it red very high. BUt, I noticed the a/c compressor was not cycling. I had to get to my destination for a party so I thought I would check it out later. The next day when I started it up, I noticed some noise. I popped the hood and noticed the serpentine belt was about half way off the fan pulley. The edge of the fan blade was starting to hit. At first I thought it was the fan clutch. But, it was tight without any wiggle. Finally, I noticed that it looked like the water pump shaft was bent. It was like it was angled over a little bit and that was why it was causing the belt to slip and why the fan was hitting. So, I assume the water pump is bad. I'm guessing these have a bearing and the bearing was failing. So, I proceeded to remove the water pump (wow what a job!). Here's the mystery. Assuming the water pump is/was failing, why was that affecting the a/c? The a/c has a separate accessory belt, right? I ended up having to order the water pump and leave my car there at family's house and rent a car.

[racer2086]

I wouldn't expect the water pump to kill your A/C unless the slipped belt affected the A/C belt somehow.

The reason your refill can read so high is because the AC compressor was not turning. This lets the high and low side equalize and read a much higher pressure than what that gauge would say for the low side if the compressor was on.

What you need to figure out is why the compressor is not turning on. That's either an electrical thing (clutch not getting power i.e. sensor reading wrong or fuse or wiring) or a mechanical thing (compressor clutch slipping or system low on charge causing the sensor to keep the clutch disengaged).

First check the easy stuff. Is the AC belt tight? Does the compressor clutch turn by hand? Was the car running hot because of the water pump? Then maybe read some codes in case it is low system pressure or something electrical.

[acspecialists]

If it was working fine on the road and died while parked the pressure went high and cut the compressor out. Unless the fan clutch is new replace it. You are already in there and they are less than $100. If it is working correctly it should sound like a turbine when you start the car and the quiet down. That being said if your fan clutch was not working the electric pusher fan should have been running to pick up the slack. If it was hot it may not be able to keep up while parked.

On another note if the engine gets hot say from the water pump failing the EMC will shut the a/c off. It does not have to be overheating just above the normal temperature. The EMC shuts off the A/C not to reduce the load on the engine but to remove the heat from the condenser going into the radiator.

[Nobleprofessor]

Turns out the bearing on the water pump went bad. it was twisting at an angle. The a/c was a blown fuse and it was a little low on freon. BUT, now I have a SES light. The code is for the AIR pipe. I'm guessing something wasn't quite hooked up tight enough. AND I have a buzzing when the radio is on.