TIP - easy way to flush coolant

[got boost?]

it's nuts for people to flush coolant by radiator drain/refill cycles, just do it like this:

1 with engine cool, drain radiator and refill with water
2 remove upper radiator hose (this is the return line from the engine)
3 start engine and turn on heater
4 refill radiator with clean water as it empties (keep water level high in rad)

once clean water flows out of the hose, you are done. replace hose, drain rad and add pure antifreeze, system should mix to ~ 50/50.

 

[Bob Woods]

Thats pretty much the way I do it, but I look in the owners manual or service manual and see what the cooling system capacity is and add pure antifreeze to equal 50% of total capacity, then top off with distilled water.

 

[got boost?]

those garden hose flush kits could damage the heater core by over pressurizing it, if you do it that way make sure to remove the thermostat and block drain plugs. also NEVER run cold water into a hot engine if using those kits.

 

[BOBISTHEOILGUY]

Got Boost, That's only true with a hot engine(overheated).

The way I do this, costs nothing and is very simple, safe and clears out all the rust/bad fluids.

1- you disconnect the top hose to the radiator.
2- open radiator cap.(1 and 2 can be reversed)
3- turn on heater(1,2 and 3 can be reversed)
4- stuff a rag into radiator where hose normally
hooks to.
5- start engine, KEEP CLEAR OF ANY MOVING PARTS!
6- put garden hose into radiator cap hole
running full blast, control flow by
restricting hose(kink hose)
7- keep water running into the radiator, this
will cause water to pour out of top hose.
Engine will stay cool, but warm up enough to
allow to flow through thermostat.

All the while, you watch the water coming out of the top hose and it will turn completely clear like the water your pouring in through the hose. At that point, the complete system will have nothing but clean water. Turn off the hose, let water blow out for a few moments, allowing for room to add fresh coolant.

Attach hose back, add coolant and water mix, put cap back on, dispose of old water/coolant. close hood.

 

[Mike_dup1]

You can buy the kits that let you cut into a heater hose, install a "T" connection, connect the garden hose and let it run. Easy to do, I have done this for many, many years. I collect the used coolant in 5 gal pails, never let it run onto the ground. You have to be careful flushing some of the newer vehicles (some GM's). They have special fill procedures and if they are not followed, you could damage the engine by creating trapped air in the system.

 

[timzak]

Seems there would still be water in the engine block/radiator after the flush is complete, throwing your 50/50 fresh fill off. Drain the petcock before adding fresh fill?

 

[terryr]

Recently I drained the rad to add electric fan, and filled it with water. I noticed later it was rusty. So I drained and refilled. Rusty again. Refilled again and again. Each time I let the engine get hot.
It took 12 refills before the water stayed clear. Then I put in de-ionized water and antifreeze.( but its only good to just under freezing.)

 

[BOBISTHEOILGUY]

quote:

---

Originally posted by timzak:
Seems there would still be water in the engine block/radiator after the flush is complete, throwing your 50/50 fresh fill off. Drain the petcock before adding fresh fill?

---

Yes, there will be some UNLESS you run your engine to the point of where the water pump isn't picking up any more water. Understand, there isn't a science to filling a radiator with water and antifreeze. It's more like a government thing, close enough is all you need.

As for the flush, it will get ALL of the rust out of your system when done that way as it is going through the heater, radiator and engine block. When fresh looking water comes out, it is clean, no more rust. Basicly it works just like the transmission flush does, takes out all the old fluid and replaces/flushes it out with new.

I'm sure there's more complex ways to do the same thing, but I've yet to see it done nor have I've seen any better results by any other means.

Have fun, what ever way you go with.
bob

 

[Pablo]

I do pretty much a variant of Bob's method, but my Volvo blocks have a drain, so I open that too.

Then I close it all up (heater on) and fill it with DI water. Drive for a day or two and then drain - the water comes out pretty clean, so the flush must have been ok.