I have a 2003 Monte Carlo SS with 145XXX miles on it. It has been overheating for the last few days. The coolant was fine, the oil was fine. Then yesterday it overheated to the point that the high coolant temp message came on. When we looked under the hood there was coolant leaking to the ground from the water pump, and what looked liked oil slung on the hood from the belt that is by the water pump. Should I replace my water pump and hope for the best or what? Also when I looked on auto zone website it said I should replace the fan cluch, but I couldn't find anything like that on their website.

 

welcome to the fourm. hope i can help u. first, get the dex cool flushed out and DO NOT put it back in. that stuff causes more trouble than it's worth. use prestone 50/50.if i were u and my car had 145xxx u might as well put a new water pump on when u get it flushed. my 04 ss 3.8 does just fine and i had a problem like yours. not a problem since. and it's been 100` in st louis and im running the air, no problems. good luck. let me know how it turns out.P.s our cars have electric fans. no fan clutch, thats why u cant find it!

 

It sounds like the water pump is the problem. Dexcool does gunk up a bit but if you keep it flushed out and fresh it works fine. I would only switch over if you get every bit of the old antifreeze out. If not your the dexcool that's left will turn to sludge. I would use a dexcool safe antifreeze, you can get it at autozone. It says safe for any color.

 

Sounds like a water pump OR a coolant elbow. Either way, you may want to replace the coolant elbows. I put a Dorman replacement on my last year when I had the top of the engine apart, then this spring when I got her out, I had the elbow push out and leak coolant all over the place. I read a LOT of people had issues with the Dorman elbows. I replaced my $5 Dorman elbows for $30 GM ones (ugh).

There is NOTHING wrong with Dex as long as you properly maintain it. Dex has been falsely blamed for years on LIM gasket failures, the real problem is crappy nylon gaskets (I've sen cars that never ran Dex a day in their lives have LIM gaskets fail because the nylon is just bad for a gasket).
There's nothing wrong to switch from Dex to the ol' green stuff, but there is no reason to RUN away from Dex. Even if you switch to green, you should still flush the coolant on a regular basis.