2000 Grand AM water vs coolant

75

Asked by JerryLL Jul 04, 2016 at 07:41 PM about the 2000 Pontiac Grand Am GT

Question type: Maintenance & Repair

Ok guys I'm sorry but this could be a long post as I feel you need to know everything I've done to maybe give an informed answer.

I have the above car. When I bought it, It would over heat on me all the time. I replaced the water pump thermostat and hoses, still overheating. So I did research on it and it turns out that I needed to burp the cooling system. Now I didn't have the money to put coolant in so I ran water and everything was great it ran (depending on how I drove it) from 180 deg to 195 deg. Next payday I bought 2 gallons of 50/50 antifreeze (green) and it ran at 210 deg to 230 deg (again depending on how I drove it). Thinking I ran the wrong coolant I bought 2 gallons of 50/50 extended life (orange) and it ran the same as the green.
I took the car to GM to have the ignition recall fixed (only made a key for me) and asked the tech why the car ran cooler on water than coolant. He explained the difference between running water and coolant but that didn't answer my question.

He said if you run water it will rust the engine unless you run distilled water. Then he told me running straight coolant the car would never reach operating temperature. Thinking like that I drained 1 gallon from the system and replaced it with straight concentrate antifreeze.

So here is my question, if it has mostly antifreeze (which is suppose to make run way below 195 never reaching operating temperature) why does it run at a constant 230 no matter how I drive it, and can someone explain why it runs cooler on water.

I appreciate your feedback

Thanks

3 Answers

103,225

I believe the optimal mix is 50/50 water/coolant. The water dilutes the antifreeze so it flows better through the radiator and water is a better 'coolant,' but antifreeze has properties needed that water alone can't provide - it is a rust inhibitor, and it doesn't freeze and has a much higher boiling point. Too much water, and it has the potential to boil away, lowering coolant levels, and causing the engine to overheat. Too little water, and the coolant mix is thicker and doesn't achieve as low an operating temperature. However that is not really an issue, so long as the engine stays withing operating ranges. With water alone, you also have the potential to never achieve optimal operating temperature, especially if you live in a cold/cool environment. I won't mention what a bad idea it is to just have water in the radiator if you live in a cold area as I think everyone knows about that. Your owner's manual will list the optimal temp for your engine.

10

The 2000 grand am takes a certain DEXcool coolant only. My question is can you use a different brand coolant? I bought a travellers brand that is 50/50 mix and am wondering if I should use it or not. I’ve been seeing mixed answers on this.

1 people found this helpful.
157,635

Do NOT use any coolant other than Dexcool, Havoline, or all makes/all models coolant! If the coolant doesn't clearly say all makes/all models on the bottle, don't use it!! Mixing any coolant will Dexcool will cause a chemical reaction that will create a sludge like substance that will clog your cooling system. All makes/all models coolant can be safely mixed with any type of coolant! Hope that helps! Jim

1 people found this helpful.

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