2008 Grand Prix coolant flush

[daviddawg]

Need to flush the coolant on my 2008 Grand Prix 3800series 3 repair manual says to get a complete drain pull the knock sensors is there a better way to flush system

[Fivefingerdeathpunch]

Pulling a knock sensor would drain the block, that's why they say to do that.

If you really want to flush everything out just remove the upper rad hose and thermostat housing. Stick a garden hose straight into the lower intake manifold and take the rad cap off. Start the car and let it run, it should flush just about all the coolant out.

Even pop the lower hose off the water pump if you want.

Then dump a full bottle of coolant into the lower intake manifold thermostat hole, fill it up with water to the top, stick the thermostat back in. Top off the radiator with coolant and water, let it run. Test the strength of the coolant bleed as required.

[daviddawg]

Thanks Buddy seems a lot easier than pulling the sensor like I did the last time I flushed the system

[SaukRapids]

I always just used Scott's thing where he takes the stat housing off, shoves a hose in the radiator and fires that piece right up. Runs the water pump and the old crap goes down the driveway.

Ol' Grumpy (my car) did it no problem, lol

[SaukRapids]

This is what I did the last couple times. Bled out fairly easy.

From Scottydogs

"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"

[daviddawg]

Thanks Buddy