can i add water to my radioter 2000

gmc jimmy red antifreeze

in new england

You should add a 50/50 mix of coolant & water. Your Jimmy’s coolant is more likely orange - which is DexCool. It is best to use that if that is what’s in it. There are also several universal coolants you can buy now.

Perhaps more important, you should find out where the coolant is going - its mostly a closed system so if you’re adding its likely from a leak. Since yours is a 2000 GM product you should make sure that it isn’t your intake manifold gasket. Check your oil to make sure it doesn’t look like a chocolate milkshake. You can also have the cooling system pressure tested to find leaks.

If you add plain water you will reduce the freeze protection in the coolant, which could lead to HUGE problems.

You can either buy the correct antifreeze for your vehicle and mix it 50/50 with water, or you can buy premixed coolant and use that to top off the radiator.

Water, by itself, should not be added.

50/50 mixture will ensure the water in the radiator won’t freeze down to about -30. Add water and that mix could raise that temp. Rarely does NE see below -10…But when it does you DON’T want to be stranded in the middle of now where with a blown engine.

If the level of the overflow tank is dropping slowly and there is no obvious leak, it may be a sign of an intake manifold leak. My 2000 Blazer’s intake manifold started leaking in Feb. 2003 at 45k miles. I was catching a whiff of antifreeze after a drive. If enough coolant gets into the oil, it will wash the oil off the crankshaft bearings.


Here are a series of articles on the GM Dexcool/intake manifold problem. One suggestion is to change the radiator cap to a Stant 10230 or 11230. The original cap was prone to corrosion and letting air into the cooling system. Dexcool has a tendency to sludge up in the presence of air.

I changed over to green coolant after the intake gasket was repaired and replaced the radiator cap, no problems since.

Last year my radiator’s side tank split near the top and had a slow leak. The symptoms were the same as the intake gasket, I was almost relieved to find it was the radiator.

Good luck,

Ed B.

Asking that suggest you need a quick history. At some point 40 odd years ago, there was a collective “why in thee hell are we doing this?” By this, they meant changing out rusted radiators and thermostats far too often and dinking around with hydrometers and having to drain down the radiator some if it failed the freeze test and worrying if you remembered to test the coolant on the tractor and wondering if Aunt Edna had her radiator checked before tonight’s big freeze and on and on. Everybody just agreed…from now on we all do 50/50 in all radiators on all vehicles in all locations. Now why 50/50? Because it’s well beyond freeze worries, coolant is cheap and its easy to remember and mix up. It can take anything North Dakota can throw at it and it works real well at 112 degress in west Texas. Also, people started to notice fewer rust problems with the radiator and thermostats. Along with that collective agreement to eliminate a pain in the butt came a collective rule: DON’T PUT WATER IN A RADIATOR. It’s not a matter of can you (although you could get to a freeze level problem). It’s a matter of keeping things simple. Find out why your leaking fluid. Also, if your at or past 100K, flush it all out and replace.

Everybody just agreed…from now on we all do 50/50 in all radiators

Well, not exactly. There is a little more to the story. The fluids used today are far different than in Aunt Edna’s time. Back then they used antifreeze. Today we use coolant. That coolant prevents freezing and during the sumer it increases the cooling capacity to help prevent overheating.

Stick with the recommended mix ratios and coolant type recommended by the car’s manufacturer.