Coolant change issue

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Okay everyone, 1994 Mustang GT, 5.0 HO. Began following the following directions to change coolant:

First: Remove the thermostat ( if you do buy a new one).
Second: Drian all of the fluid ( drain will be located on bottom left or right of radiator, its just a little plastic bolt).
Third: Cap the drains, replace your thermostat and fill the radiator with the suggested or correct amount of radiator flush.
Fourth: Fill the remainder of the radiator with water all the way up to the fill line.
Fifth: Start the engine and let it run for 10-20 min.
Sixth: Drain the water same way as coolant.
Seventh: Fill the radiator with just water to the fill line, than start the engine and let it run for 10 min. Repeat this step another 2 or 3 times to get all of the flush out.
Eight: Drain what is left of the water, than close the drain.
Nine: Fill your radiator with 50/50, coolant/water and your done!

Got through step 2 and I'm confused. Coolant is drained from radiator, but what am I supposed to do to drain block/resiviour. Not sure that it matters, but it turns out car didn't have a thermostat in it (Thanks PO) Anyway, I'm not well versed on coolant flushes so if someone could tell me the steps needed to finish, that'd be great. Thanks!
 
do you really need to use the chemical flush? you are correct, draining only through the radiator drain will leave a lot of coolant/water/sediment in the block. I would remove the lower hose from the water pump to help drain the block, and also look for drain plugs on the block itself. of course, no matter what, some liquid will remain in the block.
 
If you want to flush it I'd drain the radiator, refill with water, and drive it a day so the water circulates and the thermostat opens. Repeat as many times as you feel you need to. What falls out when you drain the rad should be at least 50% of the capacity so you can just replace with pure coolant to 1/2 rated cap when you're satisfied you've flushed enough out.

You'll be fine running on water for a few days as far as corrosion etc.
 
Is the car does not have a t-stat where it is supposed to have a t-stat?
If yes, you may want to install one.

Check youtube, they probably tell you where the t-stat suppose to be.
There is probably somebody showing you where the engine drain bolt is located also.

If not, check the appropriate forum for your specific car.
 
Always remove the block plugs if possible. Too many times I see engines that need a good ramming with a screwdriver just to get anything to come out.

They are in the very area where junk is going to settle. Bust them open and let the debris come out.
 
During the flush and rinse cycles, I would leave the thermostat out so it easier for the water to circulate through the system. Replace thermostat when u are ready for the new coolant. 50/50 give or take 10% either way, you will be fine
 
The drain plugs will be low on the block maybe 1" above the oil pan. They may be brass. They may not come out easy unless they are removed yearly which is done on boat engines.

I would not have used any chemical unless the engine was overheating. Usually a drain and fill is fine. Or flush with water.
 
Be cautious when you first drive it with the thermostat installed. Previous Owners are known to leave them out when the car has an issue at temperature.
 
Originally Posted By: eljefino
If you want to flush it I'd drain the radiator, refill with water, and drive it a day so the water circulates and the thermostat opens. Repeat as many times as you feel you need to. What falls out when you drain the rad should be at least 50% of the capacity so you can just replace with pure coolant to 1/2 rated cap when you're satisfied you've flushed enough out.

You'll be fine running on water for a few days as far as corrosion etc.


x2 on just refilling with water. Go to the grocery store and fill up on distilled for $.88 a gallon.
laugh.gif


I must admit, I didn't know you could drive the car on straight water for a few days.

I plan on doing 3-4 drain and fills with distilled on my Jeep then on the last drain, just top off with straight G-05. Should be a little more stout than 50/50. Doing one d/f per day sounds easy enough.
 
Last edited:
Originally Posted By: dlundblad

I plan on doing 3-4 drain and fills with distilled on my Jeep then on the last drain, just top off with straight G-05. Should be a little more stout than 50/50. Doing one d/f per day sounds easy enough.


A very good plan and exactly what I do. You can do more than one d/f per day as long as you drive the car ~10 miles b/t d/f. Also turn on the heater while driving.
 
Here's how I did my Sport Trac a few years ago:

Drain Radiator
Remove top hose from radiator
Remove Thermostat & reassemble housing
Fill radiator with water & put the end of the garden hose in the radiator
Start engine
Turn on water
When water runs clear out top hose, turn off water
Let the engine run until flow from top hose stops
Fill radiator with 50/50
Start engine
Keep adding 50/50 to the radiator until water runs green out of top hose
Turn off engine
Replace top hose to radiator
Fill radiator with 50/50 & install new cap
Install new thermostat
Add 50/50 to overflow
Idle engine until hot, keep filling overflow until level stabilizes at 'Max'
 
Why not do a drain and refill of 50/50 every year or two or three? Seems like a lot less work with the same benefit.
 
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