Antifreeze Mixture - Lowest Temperature

[Nick1994]

First off I'd like to say that I do understand this car is going underwater and sinking fast and probably won't last much longer. Just trying to do my best with what I can.

So my mom's 2003 Buick Rendezvous 3.4L is overheating. The thermostat stuck closed in May and she overheated it and blew the head gasket. Exhaust gas is getting into the coolant. It has a new Murray "high flow" thermostat in it.

The car has only distilled water in it and no antifreeze. I'd like to know what mixture of antifreeze and water would make it run the coolest, I have a gallon of Dexcool concentrate. The car does leak coolant (water) somewhere, probably the intake manifold gasket. Not sure. The oil level is perfect and looks great, every time I change it it looks fantastic. I know that isn't scientific at all or very accurate. It's been losing coolant for just over a year now. It's currently at 143k miles.

She just needs to be able to get to work with the car and it doesn't overheat on the freeway, but once stop and go is incorporated it starts to run warm. The electric fans work perfectly as well.

Just trying to make the best of a bad situation with the car. She can't currently afford to have it fixed or buy another car and we'd like to limp it along for a while. It's also 110+ degrees outside.

Does that "Water wetter" stuff work?

Thanks guys.

 

[dishdude]

Antifreeze raises the boiling point (along with the pressure of the system) so it might be a good idea to do at least 25% antifreeze. I'm not sure I would waste money on any miracle treatments.

 

[Brad_C]

As dishdude says, antifreeze will raise the boiling point for a certain pressure, but what he didn't say is it reduces the cooling capacity. The more antifreeze the worse the coolant moves heat. Short of liquid sodium, 100% water is about as good as it gets for moving heat around (ie specific heat, and heat transfer).

We had a ford laser (mazda engine) that I lent to a "mate" and he cooked when it popped a heater hose and he "tried to baby it home on the freeway for 10km". From that point on it was only manageable with 100% water. Any other coolant would cause it to overheat.

The biggest problem is if it is losing coolant, you won't be able to keep the system pressurized enough to keep the boiling point under control. More glycol will help stop it boiling, but it might also cause it to overheat because you can't move enough of it to keep things cool.

If you were to try anything, generic low silicate glycol is what I'd go with.

If it's getting warm, but not overheating I'd stay with the water.

 

[michaelluscher]

Flush the Dexcool mess out, and remove the thermostat

Fill with 25% Dexcool and 75% water, bleed, and keep topped up

Then tell her to start saving for a proper repair

I assume in Phoenix the A/C is always on?
Good, keep it on, it commands both cooling fans on a constant low speed.

 

[Nick1994]

Is there a way to make the fans blow on high all the time when the car is on? Like a jumper wire?

 

[michaelluscher]

Originally Posted By: Nick1994
Is there a way to make the fans blow on high all the time when the car is on? Like a jumper wire?


IIRC unplugging the Coolant temperature sensor would do so, but that's a bad idea waiting to happen.

Leaving the Air on keeps them commanded low, will step up to high when temperature call for it.

 

[Kawiguy454]

i would also just use plain water and throw an extra container in the car. ...if you hardwire both fans on high you may run the battery down if it idles alot in stop and go. If you really want to get the heat out I have seen peeps with the hood taken off in Phoenix.

...keep an eye on the oil too when you shut off the car the pressure may push water into the engine it will look milky and eventually you'll spin a bearing somewhere..

Fix head gasket leak back in the day was a bottle of bars leak ...worth a try.

 

[Merkava_4]

Originally Posted By: Nick1994
I'd like to know what mixture of antifreeze and water would make it run the coolest, I have a gallon of Dexcool concentrate.


50/50 DexCool and distilled water. Mix it in a container before pouring it in.

 

[NHGUY]

Buick Rendezvous,at one time Tiger Woods favorite vehicle to hawk...

 

[TFB1]

Originally Posted By: Brad_C
As dishdude says, antifreeze will raise the boiling point for a certain pressure, but what he didn't say is it reduces the cooling capacity. The more antifreeze the worse the coolant moves heat. Short of liquid sodium, 100% water is about as good as it gets for moving heat around (ie specific heat, and heat transfer).


THIS, the more antifreeze added the less efficient the cooling system is... Sooo it's sort of a double edged sword, but straight water without any rust inhibitors is going to cause rust and scale, eventually clogging radiator...

 

[Brad_C]

Originally Posted By: TFB1

THIS, the more antifreeze added the less efficient the cooling system is... Sooo it's sort of a double edged sword, but straight water without any rust inhibitors is going to cause rust and scale, eventually clogging radiator...


We get long life coolant concentrate here (where we don't need freeze protection) in 1L bottles. 1L does 15L total (so 6.6%) and my cooling system is 8L, so I just use the whole bottle. It is just on 30% glycol so I'm putting ~300ml of glycol in an 8L cooling system (~3.8%) and receiving full corrosion protection. WIN! Iron block, alloy head, no rust or corrosion and near enough to 100% water efficiency.

If water is working for you (even if only just) look for some high concentration corrosion protection and go, go, go.

 

[punisher]

This is just one special situation where you might be better off with just water and some sort of additive like "Water Wetter".

Water pump seals might have wear problems with straight water, and the more antifreeze you run the less the heat transfer.

 

[Ethan1]

Take out the thermostat if you're just trying to save up for another car or a used motor. This will be 100x more efficacious than any change to the coolant mixture.