Best way to flush coolant system?

What is the Best way to Flush the coolant system? How do you do it with the engine hot w/o burning your self?


I am trying to get it all flushed out before I put in my new radiator, water pump, thermostat, t-stat housing, etc. I am running distilled water and a box of baking soda now to loosen up some of the crap that is in there.




Water and Bakin soda wont hurt the enviroment so I can change this stuff anywhere! I plan on doing this a couple of times before the new stuff goes in.

L.R.

drain it cold...run a cleaning agent of your choice for a couple of days...and drain again.

refill.

prestone flush 'n' fill kit is GREAT!

BG Coolant flush machine

-Will

red91inWA said:

drain it cold...run a cleaning agent of your choice for a couple of days...and drain again.

refill.

Click to expand...

By disconecting the lower radiator hose (right of of the water pump)? or by some other method?



L.R.

LoneRanger said:

By disconecting the lower radiator hose (right of of the water pump)? or by some other method?



L.R.

Click to expand...

Correct...I'd take the upper hose off as well and run some distilled water through it till its clean.

Don't know if it's practical for you, but there's someone here who said he's been hooking a garden hose up to his water heater, and backflushing with hot water. Seems to get good results...

When you're done cleaning and you're ready to fill it up properly, see if you can pull either the block drain (8mm square drive, near the exhaust collector) or the Coolant Temperature Sensor (for RENIX, it's on the lower driver's side of the block, above the oil sump rail. May be the same for later models...) to drain from as low in the system as possible.

5-90

I let Jiffy Lube do mine. They flushed it twice with water before it came out clear.

5-90, its not on the lower block for later years (its on the back of the head).

Those block plugs on mine are something like the wierd 8mm square size used on Pug trannies. Also, they used some sort of threadlocker on mine, I have never got the front one out and have always had to jack the hatch end of the jeep way up then try suctioning (shop vac) the remainder out with a shop vac. Don't know if this is really a good idea but it seems to work as the XJ takes the exactly prescribed 3.5 gal coolant refill.

He said he was doing the water pump, seems to me that that opens the whole thing up and he could spray in there with a garden hose while he has it open after doing his flush thing.
Short of the drain plug thing the only way to get all the coolant out is to either put it on a machine that will draw a suction on the system and will leave it dry pretty much. To remove all the 'stuff', old coolant, cleaning solution, etc then the prestone kit would be your best bet. Never thought of using a wetvac for that though. Might work if you disconnect the top hose at the rad, plug the bung on the radiator and tightly seal the vac hose to the upper hose. But I would duct tape vac hose at both ends where they go into those end adapters to seal out any air leaks. You should be able to draw a vacumn on the system that way but I don't know if it would be enough to draw the heater core out.
I know when I use the snap-on machine even that does not get all the old coolant out, the last bit of coolant comes out on that when you pump the new stuff in, it pushes out the last couple of pints and you can see the old dark green coolant change color to the new bright green color in the return hose to the machine.
The prestone back flush kit gets it all out and provided you get as much of the old coolant out as possible by dropping the lower hose then putting the rad filler neck adapter on and adding a hose to it long enough to reach a 5 gallon bucket you should be able to recover all the old coolant using the back flush method. Just make sure to turn you heater on hot so the valve is open and the core gets put in the loop.

kevin s I had read that allready, but it turned into a pissing match over thermostat temps 180* or 195* and had no REAL info on what the best way to change the fluid is.

Drain it. Flush it with water using the prestone flush and fill kit. About $2.99 at walmart. Drain out water and fill with white vinegar. Run for 2 days. Drain again and watch all the crud pour out. Hold your nose. Backflush it again with the hose and refill with your favorite coolant and distilled water.
This is the best way I have ever done it.

LoneRanger said:

kevin s I had read that allready, but it turned into a pissing match over thermostat temps 180* or 195* and had no REAL info on what the best way to change the fluid is.

Click to expand...

...so true!! LOL. If you look at it again, the thread sort of got hijacked towards the end into more useful info on flushing. Yeah, the 180 t-stat has been beat to death.

At any rate, I think you have the gist of it by now. Have fun.

Cascade.

Seriously, use unscented automatic dish washer detergent, about 3 to 4 ounces, as your coolant flush. Take the t-stat out and run it for about 20 mins with the heat on. Drain, flush with water and fill with coolant. Redline Water Wetter is a good coolant additive.

--Matt

I heard that water wetter had serious issues with engines. It makes the block and head absorb more heat, thus keeping the coolant cooler. Just what I heard

I've been using Water Wetter for about 4 years in two different cars with no issues.

My Jeep never goes about 200 - 210.

--Matt

It makes the block and head absorb more heat, thus keeping the coolant cooler.

?? So its absorbing more heat from the cooler coolant??

Its amazing the BS people invent to explain why their cooling systems dont work.

I open the drain with the radiator cap on, this way it sucks the coolant from the overflow container.
Then I remove the overflow container if it is dirty and I clean it.
I pour a container of Prestone Flush, fill up with water and run it with the heater on for about 15minutes.
Let it cool, drain the radiator, leave the drain open, put a water hose in radiator, start engine, keep draining with the hose keeping it full until the drain shows clear water. Turn engine off, let cool, fill with the 5 year green stuff, if it needs more, I use some distilled water.
Seems to work and gets all the old stuff out.