Overheating problems

Hey all, I thought the water pump was leaking on our aveo so I got a new gasket and replaced it (had done the timing belt and water pump all 10k miles before). I am still getting leaking and I think it's the tstat housing actually, it is the upgraded 2 piece metal part, not the oem plastic part, and it looks like it's leaking there.

Well today my wife says the car keeps almost overheating, but the coolant is full. I have also replaced both radiator hoses during all this work. It has to be the tstat sticking or the water pump broken right? What else could it be? It's even pretty cold out here around 50s this morning, and she was cruising at 60mph on the highway. I'm pretty sure the coolant is not circulating. Any help please, I am nearly stuck. I'm pretty mechanically able too, so I'm getting frustrated that I can't figure this out.

And how does a water pump "go bad" or "break"? Isn't it a direct shaft that connects from one side to the other, so if the timing belt is turning the pump isn't the fins on the other side spinning, moving coolant?

I did some googling and found out there is a vent/weep hole in the pump that will vent coolant out (leaking) if the pump is going bad. I have a bearing noise in this area(belt area) that started when we noticed the leak, do you think the almost brand new pump could be bad and is venting/weeping? I just assumed the bearing noise was from the leak getting on either the tensioner or idler pulleys. Maybe not though? I feel like I should just put the oem stock pump back in, even though it has over 100,000 miles on it. I don't trust another "new" one, if this one failed within 10,000 miles and is causing me so much time/trouble.

Any help appreciated. I'd hate to do the whole job again and not solve the issue. I've even thought about buying an entirely new timing belt kit with new pump and redoing it, but I'd hate to spend $200-$300 and it not be fixed. I'd rather throw the old pump in and have it last 40,000 or 50,000 miles then buy a whole new kit and redo it then (at the 60,000 mile belt interval).

i think you have answered all your own questions! seems like the waterpump is failing. noise(bearing)+ leaking = failure.change out the pump.i would purchase another brand after market 1.

Is it possible for the timing belt to turn the water pump gear, but the impeller on the other side of the pump is not spinning? As in, could the shaft break? Because even with a leaking/squeaking bearing, I'd expect coolant circulation from the pump...right?

heres a pic not much help thoughAttachment 5399

Thanks. I am pretty sure it's the water pump seeing as I'm getting grinding/bearing noise in that area and a coolant leak (which I now think is the vent/weep hole). I think I'm going to stick the original pump back in. I don't want to buy another aftermarket one and have it fail in 5k miles like this one. The original one has no play still and no noise when spinning it, it spins freely.

The only thing I don't understand is that I would still think the water pump would be moving the coolant even with a noisy/leaky bearing/seal. Unless the shaft broke. I don't think this happened though, but who knows...

it could or it couldnt. the parts could have separated, the fins could have broken off, there are a few possibilities.

some failed water pumps:
http://i64.photobucket.com/albums/h1...water_pump.jpg
http://img.photobucket.com/albums/v2...e/DSC00063.jpg

Thanks. So if I pull the water pump and it is not separated like that, what else could it be? I'm going to buy a new pump and swap it out tonight (I'm getting good at doing this procedure lol....probably only about 2-3 hours this time).

its doesnt need to be completely separated to not work effectively.

aside from the leak, bearing noise, what is the over heating problem? is it just on the gauge, is it boiling over? when does it happen? etc..

My wife said while driving to work the other day on the highway cruising at 60 mph (about 50-60 deg F out) the gauge got up to about 3/4 way. It normally is at just above half way. She said it happened to and from work.

The car has been getting hot like that for a while now due to it leaking coolant (which I now think is from the water pump vent/weep hole) and she wasn't topping it off but maybe once a week or two weeks and it'd get low then get hot. I don't believe it's ever got above 3/4 though. When the coolant would get low she said it'd get up to 3/4 when stopped at a light or something, then when moving it'd cool down to half rapidly. I think this was because it was low on fluid and air was in the system.

Well now the coolant is full and it's getting hot on the highway so I think the water pump is bad. Plus there's the noise and the leak in that area.

Well i would certainly address the water pump as a "primary" issue. But the original issue of getting hot while stopped sounds like the fans/fan relay need to be verified they are in working order, as well as that the system was properly purged of air and that the correct coolant has been used throughout.

No sorry I think I'm confusing the issue....

The fans do work.

The reason the car was getting hot while stopped was because she'd let it get low on coolant (letting it leak for a week or two without checking it) so it was very low and air got in the system. Then once it'd almost overheat she'd fill up the coolant and the cycle would repeat every week or two. Just laziness on checking it is all. I couldn't pinpoint the leak, I though it was the water pump gasket, but now think it's the weep/vent hole in the pump. I actually replaced the gasket again a few weekends ago.

The new issue is that it gets hot while cruising and full of coolant. I don't believe coolant is circulating. So I'm thinking water pump(especially because of the noise and leak in that area which I now realize is most likely the weep/vent hole). Also it could be tstat (only about 10k miles old) or a clog (doubt this).

Does this all sound logical?

The replacement pump I put in just looked cheap, it came with the gates timing belt kit. I believe the impeller was plastic. Just looked and felt cheap compared to the oem one. I believe it was from china or something.

To me it sounds like you should replace the water pump, flush the whole system and then if the problem is still there, address it here.

Well I guess I'm getting good at this, just changed the water pump with a new one from autozone (duralast brand) for $60. New gasket also. Took 3 hours from the time I opened the garage till closed the garage. All I have to do is put the serpentine belt on, fill with coolant, put airbox on, and put wheel/tire on. Maybe 30 min of work. We will see if this fixes it. I'm thinking while it's empty I oughta just replace the tstat and housing ($27) because I know it's leaking anyway...

Oh and the old pump didn't really appear to be broken in any way. It was definitely not as smooth to spin as the new one (or the original for that matter).

Finished it up and bought another new tstat and housing as well. The grinding/bearing noise is 100% gone (water pump), and there does not appear to be any leaking. Car did not overheat tonight on about 3 20 minute drives. Sat at autozone with AC on idling for at least 10 min (wife in car). No issues, appears to be good :)

So the culprit was a failed water pump (cheap part, less than 10k miles on it). Came with the gates timing belt kit. Also, the tstat housing was machined poorly, and wouldn't completely seal. I'll post pics of that later...