ok , 2000 monte carlo ls has 112,miles car is driven every day an runs like a TOP ! yesterday the temp. outside was around 50 when driving the temp gauge only gets up to about 1/4, if your in heavy slow traffic the gauge might go up to the 1/2 mark the heat works fine the car doesn't missfire or nothing. so yesterday whyl I was having the oil changed i asked them to check the coolant [antifreeze] they told me an SHOWED ME what looked as if ther was oil or mud in the radiator and the over flow bottle ?? there was NO anti freze in the oil !the oil that was drained out was even clean looking not milky,Transmission fluid looked nice and pink/red ! so they changed the oil an filter and i drove the car probly 55miles or so and it ran an acted the same as it has since i'v owned it I even ran the crap outa it tryin to get it HOT. where does the fan kick on at on gauge? i know 1or both fans are on with the a/c but even powerbraking/ i couldn't get it hot enought to kick a fan or past 1/2 on that gauge? but my concern is MORE with that oil in the radiator ?

sorry for such long qustion i just wanted to give as much info as possible !

 

Its probably not oil. Its probably a combination of rust and mixed coolant. Dex-cool is known to be very corrosive and if you mix it with green antifreeze, it will form a redish brown sludge. I recommend flushing the radiator and engine completely of the old antifreeze and switching to green glycol based antifreeze.

 

Old Dex-Cool.

We hit a huge piece of tire on the highway one day, it ripped the air deflector thingy off underneath and my fans didn't kick in until it was a few marks past the halfway mark.

 

I agree w/ MRL, you should probably flush out the radiator and switch to something different. Dexcool is known for eating seals and causing leaks (i have replaced the LIM gasket on my car twice now). Glycol based (green) antifreeze is fine, but for newer radiators most auto shops will suggest the orange universal coolant sold at most auto parts stores.

edit: if i remember right, stat kicks on at 190, and fans should kick on at 200 or 210

 

I agree with everyone previously posted. It doesn't sound like you're descibing a serious condition of failure, but you are describing that you are probably at a maintanance point.
People tend to neglect fluids like anti-freeze, but the chemicals in any anti-free (Dex and the ol' green stuff) do break down, do get "brown" looking and do create sludge deposits in the system.

I would recommend since it sounds like the coolant was never flushed, get it flushed, and it may not hurt to replace your T-Stat (again, those wear out over time). But sounds like things are "ok", so long as you do some recommended maintanance.

 

thanks for the help