How to determine bad water pump

[vhandobi]

How do I determine if my water pump is or is going bad? I have a '92 Lesabre.

It started with a small engine noise. Sounding possibly like something was scraping or bearings were going bad (although it is hard to describe a "noise") Anyway the first thing I looked at was the harmonic ballancer. I had an old Park Avenue that had the ballencer go bad and caused me to look everywhere but at the ballancer. However, on inspection the ballancer seems fine.

I pulled the belt off and the noise seems to go away. However I want to try this again when the engine is hot as it seems the noise is more pronounced at that time.

Without going out any buying several different size belts (to individually power different components) how can I tell if something is going bad? Specifically I'm looking at the water pump now. That "seems" where the noise is comming from, then again it is always difficult to pinpoint a noise in an engine.

I don't seem to have any fuel problems, no check engine lights or anything else has occured to indicate any problem has occured.

Thanks.

[avatar307]

Hmm... borrow a stethoscope and place the vibration pad near each pully. That will allow you to narrow down the noise very efficently.

However, I can tell you that the noises you are describing are the same noises I was describing before I replaced my water pump.

The gasket was leaking already, and the car had 175,000 miles on it, so I elected to spend $24 and change the water pump. Unfortunately, I now suspect the gasket included with the pump was junk. I will be changing it today, as the new water pump gasket is leaking.

When I pulled the water pump, there wasn't anything visually wrong with the insides. Beyond that the new pump was of a better design, more effiecent impeller. However, upon turning the pulley without any coolant to provide resistance, you could feel the bearing begging to grab as it went around.

Usually when a bearing starts to go, it's very subtle. About the only component you can detect it on is your alternator, but turning, spining, or pulling the spaft. (Mostly you do this just to pretend you know what you're doing.)

You can take the belt off the engine and turn the water pump pulley very slowly. You may be able to feel something catching as you rotate it. Odds are it will catch in only one place in a rotation, and only for a second. At 1500 RPMs though, it makes a very distinct noise.

Usually the part that fails in water pumps, on any engine, is the bearings. Eventually they will fail, the water pump with lock up, and you'll be screwed. You'll be able to cut off the $40 belt and drive 100 feet before it dies from lack of alternator.

A water pump costs $24. That's not the biggie with replacing it though. The biggie is that it's a big pain in the..... You're 92 is likely just like my 95. You'll have to lift the front of the engine up about 6 inches, remove the front engine axis mount, and front engine axis bracket before you'll even be able to take the bolts out.

Stupid water pump. Stupid gasket. I'm procrastrinating doing it. I haven't had enough sleep to be excited about it.