Thread: Coolant System Flush

I'd like to do a coolant system flush on my car since I haven't done one since I first got in over a year ago, and because my TEMP light started to come on today so I guess it's starting to overheat a little bit. I can't find a write-up on how to do it, could someone point me in the right direction? Thanks!

umm its called the drain cock (like what you call a roster). Also your directions leave tons of dexcool in it. you need to drain the raditor then leave the plug open and run water in it for about 10 mins. this will flush all the old coolant out and leave you with water in there. Next lets the water drain out then fill it back up with what ever you like. and don't for get to bleed the system of air.

that prestone flush stuff is handy if its got gummed up dex, its like a detergent.

this video gives ya basics, nothing specific but its kinda handy



if youre worried and not afraid to spend a few extra bucks, buy premix, but its almost fool proof,

Bleeding is the key element, and it will bleed itself a little over first few days of driving.

also take and maybe change the thermostat, and flush the lim seperately with water, same as heater core, dex loves to hide there.

I remove both rad hoses, the lower gets removed from the rad, and the upper gets removed from the engine. I remove the thermostat and radiator cap. Then I flush the Radiator, engine block, and heater core separately with a garden hose on full blast for at least 30 seconds each way. Flushing, and back flushing. It's important to get all of the coolant out if you're switching from dex-cool to conventional. I did this and don't have a speck of brown sludge after the switch.

Okay I'm hearing you all talk about this, how do I flush the engine block and heater core?

the one reserviation i have about premix is that it cost more i just get the pure stuff then mix it my self 2 one gallon jugs makes 4 gallons. and its half the price.

I just bought 2 gallons of pure stuff and added it to my cooling system after the flush (engine block full of water). It's a 13-ish quart capacity, and I added 6 quarts of pure antifreeze. That's just about the 50/50 you want.

And flushing with water using a hose is the way to go. Back flushing gets some more crud out and changing the t-stat restores the cooling system's efficiency.

also a side note if you really feel up to the challenge of getting it perfect then you could (not saying you should) replace the radiator, heater core, and hoses to bring it back to perfect. but most don't because of cost and time.

Originally Posted by Dadillac

I did my sons car like this. Removed the lower radiator hoses from radiator. Removed the thermostat housing and kept it attached to the hose. Used a hose nozzle wrapped in a rag and inserted it into the intake where the thermostat sits. Ran water for several minutes. Reversed the flow by shooting the water through the lower hose so it came out the intake. Once it ran crystal clear I disconnected the heater hoses. Used a small nozzle and flushed the heater core and hoses going both directions. I then rinsed out the radiator same method, both directions, until crystal clear. put the lower hose back on the rad and added 1 gallon of 100% coolant. Then added 50/50 mix until it flowed out of intake. Installed new thermostat and closed it all up. Topped it off and bleed it out. Good to go

Don

this works well, but if you put the lower hose back on, leave the T stat out and the upper hose on the housing, and off the rad. put the hose in the rad, fill it up, then start the car, run it till clear water comes out the upper hose, then turn the hose off, then run the car till no water comes out the upper hose. turn it off. then put the T stat back, the upper hose back, then dump one gallon of straight antifreeze in the rad, start the car full the rest of the way with hose water.


then idle the car rad cap off till the fans turn on, then bleed the air out of the t stat housing, top off the rad as needed as it warms up, if it burps and the rad level drops, the T stat opened up for a a few seconds and took the coolant, the cold water from the rad made it close again.

waiting for the fans to come on means its hot enough that the T stat should be wide open.

you can also pull the heater core hoses off the back of the engine, and flush it both ways with a garden hose. then put the hoses back on, but fill the hoses with water so no air gets trapped in the core.