Mixing Dexcool with All color All purpose Prestone.

[ChevMali99]

Hi folks, long time no see. It's been a while thankfully since I've had a problem with my Malibu 99 3.1, actually the few problems I've had I've basically ignored, like the rattling in the trunk or the off and on AC or the driver seat that no longer reclines. There's a problem that I can no longer ignore because... well it could become significantly expensive and that is - Leaking antifreeze. I've been using the Prestone green for all colors and all makes for a while 6 months or so, today the car's temperature range was unusually wide and the red light indicating low anti-freeze was coming on and off. I pulled over and the reservoir was adequately filled yet there was a trickling on the driver's side. I'm not sure of the cause, is it a cracked radiator or a loose knob? I popped the reservoir open and the vacuum effect ceased and antifreeze fluid over topped the reservoir... Weird. I'm gonna take a look under the car and attempt to see where the leak is coming from but any help or recommendations will be greatly appreciated.

[ChevMali99]

I was looking around under the car, around the top of the radiator, and around the usual spots known to be related to the exhaust manifold problems that plague the malibu and other chevy & GM cars, and nothing - all is dry; except the driver side of the radiator. I imagine there is a crack because the hose is dry.

Now something interesting I discovered, maybe I'm imagining things or this is an effect that occurs from mixing Dexcool with Prestone's all color all makes antifreeze; it seems to make the gunk less sticky and soluble. I noticed this by adding more Prestone to the reservoir and the gunk that was in it floated. I removed some with my finger and instead of it being sticky as I remember it, the gunk was oily and disintegrated upon rubbing it between my fingers.

[ChevMali99]

Just bought a radiator for $100.00 gonna have it installed tomorrow for another $100. While making quick runs I noticed antifreeze was leaking at a faster rate. Popped the hood and all the troubled spots were dry, almost confirming a damaged radiator. We'll see tomorrow.

[j cAT]

dexcool GM approved coolant is not prestone compatible coolant. these are not to be used together.....................

Prestone now makes dexcool GM approved coolant . if the container states GM approved dexcool than this is what to use.

since you mixed these together good luck with the damage.

the only way to fix this is an acid flush . replace the hoses and then install dexcool or whatever other coolant you wish. but do not mix them ..I would also mark the fill cap as to what coolant you ended up using so that no one puts the wrong coolant in there... this is excatly why dexcool gets a bad rap.......mixing !

USE DISTILLED WATER WITH THE COOLANTS ..NO TAP / WELL WATER ..

[Ed_Strong]

I would also replace the thermostat as a good measure!

I would hate it if I get everything buttoned up and ready to go and find out that the cause for

"the car's temperature range was unusually wide and the red light indicating low anti-freeze was coming on and off"

as you mentioned was caused by a thermostat stuck in the closed position, not allowing coolant to circulate!

[autojoe]

also use distilled water for flush and do a couple times to get any of the flush residue out.

[FISH96]

does anyone know if they OE fill at the factory uses distilled water?

[autojoe]

the ph of the water will affect break down the inhibitors in the coolant which is 1.5-4%......the inhibitors prevent corrosion.only is it good to test freeze/boil point....also the ph.
Prestone team highly recommends that shops and DIYers use distilled, deionized or quality soft water during flush and fills to minimize potential contamination. Ions and impurities that are sometimes present in poor quality water can attack and/or adhere to metal surfaces in hot heat exchangers and cause scale build up. Also, some municipal water carries chloride, chlorine and sulfate, which can cause corrosive issues.
different ph range for conventional coolant or extended life coolant.
i dont know what prestone uses but probably deionized water.

[j cAT]

Originally Posted by autojoe

the ph of the water will affect break down the inhibitors in the coolant which is 1.5-4%......the inhibitors prevent corrosion.only is it good to test freeze/boil point....also the ph.
Prestone team highly recommends that shops and DIYers use distilled, deionized or quality soft water during flush and fills to minimize potential contamination. Ions and impurities that are sometimes present in poor quality water can attack and/or adhere to metal surfaces in hot heat exchangers and cause scale build up. Also, some municipal water carries chloride, chlorine and sulfate, which can cause corrosive issues.
different ph range for conventional coolant or extended life coolant.
i dont know what prestone uses but probably deionized water.

I want to add that my testing of some of these pre-mixed coolants are less than 50% of the coolant .

I do install 65 % coolant to 35% distilled water to ensure max corrosion protection with all coolants after 20 years now no corrosion ..

[slls]

I use tap water. Have a 14 yr old Sonoma and no problems, yes still has dexcool.

[j cAT]

Originally Posted by slls

I use tap water. Have a 14 yr old Sonoma and no problems, yes still has dexcool.

tap water quality is very variable . you are lucky . good gamble. cost of the distilled water is 1 buck per gallon , so not worth the risk IMO....

[FISH96]

I shall ask again. Does anyone know for a fact that the OE car manufacturers both foreign and domestic
use distilled water in the factory fill of the cooling system?

[j cAT]

Originally Posted by FISH96

I shall ask again. Does anyone know for a fact that the OE car manufacturers both foreign and domestic
use distilled water in the factory fill of the cooling system?

In the OEM GM manual the use of distilled water is mentioned to be mixed with the coolant .

when DEXCOOL was used by GM this is when GM came out with the distilled water. I was ahead of GM with the use of distilled with the green silicate based coolant formula. got 380,000miles out of my 1983 gm vehicle with no coolant issues. no scale or corroded internal damage. prior to the 1983 I did have problems with the coolant system . used tap water and got all the bad issues with this damaging water. too much metal and chlorine.

toyota has only pre-mixed coolant for specific years and this is distilled water.

I doubt GM would put tap water in the factory vehicles but if they used tap water it would not surprise me just to save a few cents. I know my coolant systems are cleaner now then when I first purchased my vehicles 18 and 13 years ago !

anyone who has others work there vehicles is at risk to have the fluids contaminated .... all the fluids. lube shops are not up to speed on this .

[stripe]

You could use water from a dehumidifier.
It is pretty close to dis-stilled and free.

Cheers
Stripe

[slls]

Originally Posted by j cAT

tap water quality is very variable . you are lucky . good gamble. cost of the distilled water is 1 buck per gallon , so not worth the risk IMO....

My 09 G6 is getting the same treatment, as all my vehicles since the 50 decade.

I think doing nothing, which most people do as far changing coolant, is more of a problem.

2 oil and filter changes ago I let my OLM go to GM change mileage. Gm thinks it's ok to go 12,300 miles between oil changes. So I don't go with them, even 100K between transmission fluid changes, I go 50K with the syn oil, 30 K with regular oil.