How Much Antifreeze in Engine/Radiator?

[Nick1994]

2003 Buick Rendezvous AWD. Going to drain the radiator and refill with Dexcool. The car only has water in the entire system, no antifreeze in it.

How much antifreeze to pour into the radiator to get close to a 50/50 mix?

I've got:
1 gallon of Dexcool
1 gallon 50/50 Dexcool
1 gallon distilled water

What ratio do I use on fill up?

 

[Olas]

Depends on the capacity of the system..

If its upto 1 gallon I'd throw the premix in for convenience, if it's more than a gallon I'd use 50/50 pure coolant and distiller water..

 

[The_Jeff]

They say the system has 9.6 quarts.

If you can drain half via the radiator, that's 4.8 quarts that comes out.

If you do your first fill with the 50/50 and the rest water, that's 2 quarts of pure antifreeze in there. Run it so it mixed, drain it, and you'll have 1 quart of pure AF.

Refill with your gallon of dexcool and you're good to go! Top the last .8 quarts off with water.

If you don't mind being slightly under 50%, just toss the gallon of full strengh in first then top off with 50/50. This would work well in AZ.

 

[Nick1994]

Originally Posted By: eljefino
They say the system has 9.6 quarts.

If you can drain half via the radiator, that's 4.8 quarts that comes out.

If you do your first fill with the 50/50 and the rest water, that's 2 quarts of pure antifreeze in there. Run it so it mixed, drain it, and you'll have 1 quart of pure AF.

Refill with your gallon of dexcool and you're good to go! Top the last .8 quarts off with water.

If you don't mind being slightly under 50%, just toss the gallon of full strengh in first then top off with 50/50. This would work well in AZ.
Thanks. It's been overheating but I remembered it's missing the lower plastic thing underneath that helps direct air into the radiator so I picked one up yesterday. I want this thing to run as cool as possible.

 

[DoubleWasp]

If it's been running pure water,,I'd do a flush first to help pull out some of the corrosion that's been undoubtedly building up.

 

[old1]

From what I have always read, pure water actually cools better than 50/50 antifreeze. It takes a lot more temp. before it will boil of course, so protects better, but won't keep the temp down. Also antifreeze has anti-rust etc.

 

[ARCOgraphite]

Can't you safely run and old school EG antifreeze instead? Id dain out at least a gallon of you not going to flush (which you should!) the put in a gallon of pure AF then top off with distilled water with the cap off - let the T stat cycle a couple times then let cool overnight, then top off, then cap.

 

[SHOZ]

What I do is on the final flush use distilled water. Then add a gallon of the straight stuff. Then top off with 70/30.

 

[Chris142]

Old school was. 1 gallon in 4 cyls,1.5 in a v6 and 2 in a standard small v8. I'd aim for 1.5 of pure to dilute the water you can't drain

 

[Oro_O]

I don't know your system, but isn't there some H2O in the heater core that can't be drained?

I had this same issue last summer. Ran dH2O a little while to clean out the wrong fluid in the system, drained/filled with dH20 a couple times. After a week or two of this, I drained the radiator and block taps, and on that car's 9.7qt system (vs. your 9.6), I was told to expect 1.7 qts of fluid still in the heater core by the Toyota/Lexus experts. So I filled with the right amount of coolant to get to 55% (9.7qts*32ozs*.55 = 170ozs). Then I topped up with dH2O. I measured out the remaining water I added with a graduated quart mixing cup - and when all was said and done it was spot on what the allowance for 1.7qt in the heater core would have predicted to get to the 55/45 mix I like to use.

So on this toyota V6, the assumption that draining the radiator and block taps would leave 1.7qts in the system was bang on.

 

[DoubleWasp]

Originally Posted By: ARCOgraphite
Can't you safely run and old school EG antifreeze instead? Id dain out at least a gallon of you not going to flush (which you should!) the put in a gallon of pure AF then top off with distilled water with the cap off - let the T stat cycle a couple times then let cool overnight, then top off, then cap.


I'd vote to replace it with G05 first.

 

[A_Harman]

Too much guesswork involved. There is no good way of knowing how much water is left in the system, so there is no way to calculate how much coolant to put in to get a 50/50 mix. When you drain the radiator, be sure to measure how much drains out, then subtract that from the 9.6 qts that eljefino says your Rendevous takes. That's the amount of pure water remaining in the system. The object is to get to 4.8 quarts of water, and 4.8 quarts of antifreeze to get a 50/50 mix.

You may get lucky, and exactly 4.8 quarts drains out, then you can replace it with 4.8 qts of straight antifreeze.

But maybe 6 quarts (for example) drains out, leaving 3.6 quarts of water in the system. No problem. Just put 4.8 quarts of antifreeze in, and 1.2 quarts H2O.

But if only 3.6 quarts drains out, that does not leave enough free volume in the system to put in the required 4.8 qts of antifreeze. Then you have to figure out a way to get another 1.2 qts of h2o out.