My camaro has recently started to overheat at highway speeds. I followed a couple posts on here and checked the airdam, coolant to water ratio, and the thermostat. The airdam is in place and in good shape, the antifreeze concentration is good, the cooling system is fairly clean and does not appear plugged, and the thermostat is working properly. The only thing I haven't checked is the water pump, now some time after the overheating started a little rattling grinding noise started under the hood. I can't be sure if it's the pump or not.

So my question is do water pumps ever die slowly with diminished capacity until they stop working? Or will it eventually start squealing and leaking like its supposed to? Thus far it has not leaked a drop.

 

Could be the pump.
IMO,
sounds like the pump is going out, eating the bearing on the input.

Use a long socket extension,
1 end on the pump,
the other against your ear. You will hear the grinding amplified if it is the pump.

 

Hey thats a neat trick, thanks for the tip I'll try that out in the morning.

 

BE CAREFUL!!

Do it from the back or side, keep hair & clothes away from the belt & pulleys!!
Use a couple extensions if needed. 8-10 inches *should* keep you in the safe zone!! If that's not long enough, put a few more together.
Use your best judgement & be careful!!!

 

Do it to the BODY of the pump,
NOT the input shaft or pulley itself!!

 

Just get a mechanics stethoscope from the parts store. Alot better than a screw driver or something.

 

Any long "stick" will do. Even your radio antenna off your fender would work. A broomstick is big & not as easy to set on a small point, but will work. Just hafta hold your ear next to the stick, since you can't stick the whole bristle in to your ear. Just be sure to avoid any moving parts & be careful.

 

well at least if I did do that I'd have some interesting pictures to post X.X

 

Actually, this gives me a good idea to check my pump out with my scope to see if there is a grinding noise before I flush the coolant. The pump is 5 years old and doesn't leak.

 

If the bearings are going out on the pump, you should be able to see some coolant from the weep holes in the pump. If you have anything coming out of those holes, the pump is bad.

 

Just tryed listening to the pump itself with a dowel rod, whatever the noise is it isn't coming from the pump. So that just shot down my theory on the overheating, but the pump is almost 4 years old is it possible that it's capacity has just diminished over time? Or am I looking at some other problem?

 

Pumps don't usually just "dimish" in their cooling capacity over time. Unless you've got a lot of sand in your coolant.

Your have a 400 block engine eh? Am I the first to notice this little tidbit? They are notorious for overheating -- BECAUSE - The cylinder heads or head gaskets may not have the holes drilled.
***Was this done?***

 

the car has cooled fine since I bought it about 2 years ago, the overheating only started just earlier this spring mid-april was when I noticed it.

 

ah ok, gotcha.

Were you the guy I recommended pulling the t-stat to see if it's flowing? I assume your v-belts are good an tight and all that?

 

Pulling the t-stat is the next thing I might try. I was going to back flush the system and replace the coolant and possibly replace the water pump at the same time, just trying to decide if its worth doing since the pump seems to be ok. And yup the belts are all good and tight.

Just by looking at the coolant it doesn't seem overly dirty or cruddy but now I'm starting to think there could be a little blockage or something. There must be something reducing the coolant flow...

 

If it were me? I'd probably pull the t-stat, and see how fast the water is flowing.
My next step would be to replace the water pump. Small block chev water pumps are hilariously cheap (like $50). I wouldn't even do any more troubleshooting myself.
I have heard horror stories that rebuild pumps only get new seals, and the impeller itself just keeps wearing down. So a rebuilt pump could be just as crappy. I personally have not had this problem with rebuilt pumps, but just a tidbit of info.

 

Alrighty thanks for all the advice, I might as well replace the pump anyway if it isn't bad now it'll probably go next month sometime.