Best way to flush coolant

blksn955.o said:

drop the lower hose off the rad. and into a bucket (prob a few 5gal. if you want to jack up the car). Undo the upper hose at the rad. and stick the hose in there (might want to do a t-stat change as well and after removing it just not install it until after its done flushing to make sure water will flow easly just bolt up the t-stat elbow though). The water from the hose will flush the engine and then reverse it by putting the hose in the rad. at the upper to flush out the rad. Then install the new antifreeze after you re-install hoses and t-stat (if you do the t-stat) and check it to make sure you have a proper mix for your weather.

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MLC Stang said:

MustangSupra,

These are all good ideas and will get the job done, but the best way I have found is to use a Prestone Flush N’ Fill Cooling System Flush Kit.

Prestone still makes a really simple Flush & Fill Kit that works great to flush all of the coolant out of your engine and replace it with a new 50/50 mix of anti-freeze and water. Most Wal-Marts and Targets carry them. They cost less than $10.00.

The kit consists of a plastic T-fitting that you splice into one of your heater hoses. That fitting has a garden hose connector on it, so that you can connect a regular old garden hose to it and use that water source to flush all of the old coolant out of your engine. The other part of the kit was is an angled plastic nozzle that fits into the top of your radiator after you removed the radiator pressure cap. The other end of the nozzle is just open.

When you hook the garden hose up to the heater hose T-fitting, turn on the hose and start your engine, all of the old coolant will pump right out of the top of the radiator through that nozzle, fly across the front of your car, and onto the ground and down the drain. (Not exactly PC today, but it works.) Oh yeah, the heater controls have to be set to full ON high heat for this to work.

Once you are done with the flush, i.e. nothing but clear water coming out, turn off the engine and then turn off the garden hose and disconnect it. Put the cap back on the T-fitting and remove the nozzle from the top of your radiator. Next, drain all the water out of your radiator by opening the bottom draincock. When it’s all drained out, shut the draincock valve. So, now you've got an engine full of clear fresh water and an empty radiator.

Now look up your car's cooling system capacity in quarts/gallons, whatever. Divide that number by 2 and pour that much pure antifreeze into your radiator. This gives you approximately the recommended 50/50 mix of water/antifreeze. (After you add the correct amount of antifreeze, you might have to add a little bit of water to top off the radiator to the correct level.)

PS) The best place I found to splice in the T-fitting on my 95 GT was in the heater hose just above and to the left of the water pump at the front of the engine. Be sure to have the hose fitting pointing in the right direction to get a garden hose connected to it before you tighten up the hose clamps.

Hope that helps.

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Methodical said:

Uhmmm. I've always looked at that kit but never knew anyone who actually used it. Sounds like a good cheap investment. ? - Do you turn the water hose up high for maximum pressure or is on low?

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sade04 said:

hey great write-up mlc stang could you possibly post a pic of where you spliced the t-fitting? are you talking about the bypass hose?

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8950HO said:

If you want to get all the crap out,you need to remove the cylinder block drain plugs after using a flushing tee.

If the block drain plugs are not removed after running water through the system,you will not get all the crap out of the bottom of the block.

So after flushing it normally,remove the plugs and turn the water back on and let it run out the block.

Makes the system easier to refill because you don`t have all that water in the block diluting your new coolant mix.
You may not even get the right concentration if you don`t remove them because theres too much water in the block.Then you have to drain some out and add more straight coolant to get the right freeze protection level.

Warning;the block drain plugs will likely be a pita to remove if they`ve never been touched before .

I remove mine when I flush the system.

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8950HO said:

If you want to get all the crap out,you need to remove the cylinder block drain plugs after using a flushing tee.

If the block drain plugs are not removed after running water through the system,you will not get all the crap out of the bottom of the block.

So after flushing it normally,remove the plugs and turn the water back on and let it run out the block.

Makes the system easier to refill because you don`t have all that water in the block diluting your new coolant mix.
You may not even get the right concentration if you don`t remove them because theres too much water in the block.Then you have to drain some out and add more straight coolant to get the right freeze protection level.

Warning;the block drain plugs will likely be a pita to remove if they`ve never been touched before .

I remove mine when I flush the system.

Click to expand...

8950HO said:

If you want to get all the crap out,you need to remove the cylinder block drain plugs after using a flushing tee.

If the block drain plugs are not removed after running water through the system,you will not get all the crap out of the bottom of the block.

So after flushing it normally,remove the plugs and turn the water back on and let it run out the block.

Makes the system easier to refill because you don`t have all that water in the block diluting your new coolant mix.
You may not even get the right concentration if you don`t remove them because theres too much water in the block.Then you have to drain some out and add more straight coolant to get the right freeze protection level.

Warning;the block drain plugs will likely be a pita to remove if they`ve never been touched before .

I remove mine when I flush the system.

Click to expand...