Coolant Flush Question

[TheRiGuy]

I recently purchased a 2007 base model Grand Prix and would like to try and perform a full coolant flush. I've never attempted to do a coolant flush before but my plan is to remove the upper and lower radiator hoses, the heater core hoses and flush the radiator, engine block and heater core with a garden hose in both directions until the water drains clear from all three. Then put in a new T-stat, reassemble and re-fill.

my questions are
1)is this an acceptable method of flushing the coolant system?
2)roughly how much water will be left in the system after the flush so i can adjust the water to coolant ratio?
3)should I re-fill with dex-cool as per the manual or switch to something else for any benefit?
4)how do I go about removing air pockets other then squeezing the hoses by hand and letting the engine run?

any advise. tips or tricks would be greatly appreciated thanks.

[Scottydoggs]

how to flush coolant:


remove the t stat, put the t stat housing back on, take the upper hose off the radiator, then push it down to the ground to a bucket or let it fly.


get your garden hose out, put it in the rad turn it on, then fire up the car, let it run till clear water pumps out the top hose.


then turn the hose off, run the car till no more water comes out the upper hose. then turn it off.


put your t stat back in, with new gasket, the upper hose back on.






now take 1 gallon of full strength green antifreeze, not the 50/50 crap. ( parts store cheap green is fine to use) dump the whole gallon in the radiator, fire up the car, fill the rad with hose water till its full. top as needed till its ready to be bled of air. it will burp and take coolant as the water in the block warms up the t stat opens up for a few seconds till cold coolant hits it and it shuts again.


now to bleed the air out, let it idle rad cap off till the fans turn on, (when the fans are on the temp is over 195 deg, the t stat is wide open) then open the bleeder screw on top the t stat housing a few turns till a steady stream of coolant comes out the hole, shut the screw, top off the rad. cap it.

[Fivefingerdeathpunch]

I prefer to fill the coolant via the thermostat opening instead of only the radiator. This require less bleed time and even no bleed time.

The thermostat opening is higher than the radiator and should help all the air escape.

[TheRiGuy]

then turn the hose off, run the car till no more water comes out the upper hose. then turn it off.

wont running the car until there is no coolant damage the water pump?

[Scottydoggs]

Not at as ll. Not lije theres a rubber impeller or anything.

[stocker]

I switched to green last year after flushing completely with water. No issues and no more worrying about Dexcool so I'd recommend switching to green.

[Bronco Boy]

3)should I re-fill with dex-cool as per the manual or switch to something else for any benefit?

Flush all the dex-cool out and go green. Dex-cool is for suckers.

[cheatah faheatah]

While you have all that apart, I would strongly suggest changing your coolant elbows to the aluminum ones. They're under 20$, cheap for peace of mind. Factory plastic ones will fail sooner or later. Not very difficult, 90 minutes tops, no special tools. Good luck! And count me in the Dexcool blows club...Greens cheaper anyway...

[TheRiGuy]

Thanks for all the advice everyone. I guess I'll be going green lol, not much love for dex-cool here it seems. I will definitely be sure to upgrade those elbows to aluminum while I'm at it.

[Scottydoggs]

metal elbows are in the help section at most parts stores, they run about 10 bucks. when you change them, clean the holes out really good, use some 120 grit sand paper if you have it in all 3 holes.

then oil the o rings on the new elbows and slide them in. not sure what year you got, but watch them alt bracket bolts, use the long one in the wrong place and you drive it into the valve cover and make a nice hole in it.