Gotta Be the Water Pump, Right?

[jgilhuly]

'00 GC, 94K

Steady, constant high-pitched chirp/whining starts about the time the thermostat is probably opening. Persists as long as the car is running and does NOT vary with engine speed. Temp needle will intermittently jump to 3/4 or more and then usually settles back down, only to go back up again later, again with no change in the noise. No fluid loss to speak of and pressure test is OK.

This has got to be the water pump, right?

Can someone give me a ballpark on what a shop will charge me for this job?

Thanks a lot....

[Bernard Feltzer]

A bad water pump makes a low pitched rumbling sound and varies sightly with change in engine speed.

A high pitched whine could be caused by your alternator, idler, and /or tensioner.
Chirping caused by belt and worn tensioner.

Assuming it is a 3.3

If it is a 3.0, I wouldn't know, since those are junk.

[RIP]

Yes and no. The waterpump is driven by the drive belt which in turn is driven by the crankshaft pully. The crank pulley varies in speed according to the throttle so...the waterpump speeds up and slows down as the engine speeds up and slows down. Your noise doesn't change with engine speed so the pump may not be the cause. Usually when pumps make a noise its because the shaft bearings fail. A sign of this would be play in the shaft. Can you wiggle the pump pulley up and down?

3.3 and 3.8 ltr engine should cost around $150. That's $30-50 for the pump plus labor. Not sure about the 3.0 or 2.4.

Though they aren't a perfect fit for your symptoms either I would lean Bernards way. The Tensioner and idler pullies are infamous for creating a "cricket" like chirp. Sometimes described as bells under the hood. I'd bet it's the most common abnormal noise heard under these hoods. My 96 has been doing it for years. I just live with it. When I hit the gas it quiets down. Went through the musical chair routine with pullies and gave up. Just kept coming back. Cheers.

[jgilhuly]

Sorry, should have specified it's a 3.8.

So if it might not be the water pump, what's the correlation (if any) between the noise and the temp? Never had a temp problem until the noise started and if it was the tensioner, etc., why would it wait till the car warms up before chirping?

[RIP]

A general correlation is that temp expands any metal and increases wear. Specifically, no concrete answer for you. Best to let experienced ears listen to it.

If you want to give it a shot, one trick is to use a short length of garden hose cupped to your ear as a stethoscope. Just direct it close to each potential source and pinpoint the noise. It goes without saying, you have to use extreme caution around moving belts etc. They will do more than ruin your day.

Before I went for a pump without more proof, I would flush the system and change the thermostat ($5-10). Could be the source of the temp flux just as well as the pump. The noise? See para #1.

[jgilhuly]

Took a while but I finally got around to this one...

Replaced the stat and the temp fluctuation stopped as well as the noise. Now I've never heard of a thermostat whining before so perhaps the last poster was right about the temp of the motor itself causing some component to make noise. As long as the noise is only present when the temp gets excessive I'm going to declare victory and move on the the next item.

[RIP]

Well, your problem has been a learning experience for all of us. I never would have thought the t-stat would make a noise. Maybe it wasn't the t-stat at all. Maybe the fact it failed made something else in the system make the noise. We'll never know. Glad to hear all is well now. What is your next item? Or was that a figure of speach? Cheers.