Coolant change on Ford Ranger

[doitmyself]

My son's '02 Ranger (4 cyl) has no radiator cap, but has a pressurized overflow tank.

How do you do multiple drain/fills to flush this thing out with distilled water? There is a radiator drain plug I think.

Thanks!!!!

 

[jhMalibu]

What a coincidence...I just did a partial change on my 09 this weekend.

There is a drain valve on the bottom of the rad (passenger side). Mine was under this small plastic shroud which is held on by four bolts.

I did a drain of the radiator + disconnected the overflow tank to rinse out the fine stuff. The overflow tank emptied as the radiator was draining. Also disconnected the lower hose (since I was under there anyway).

It took a little under 2 gal to refill.

Hope this helps.

 

[doitmyself]

I would like to know how this system works.

When you open the radiator drain and/or take off the lower radiator hose, does the overflow tank empty by gravity. Or, do you leave the cap on and it drains via vacuum (I have tractors that do this)?

When you refill thru the overflow tank, does coolant fill to the top of the radiator....again by gravity?

It seems like this system/method would end up with air pockets in the radiator or other places.

Thanks.....This system is new to me.

IN OTHER WORDS, DO I JUST FILL THIS SYSTEM THRU THE OVERFLOW CAP AND TREAT IT JUST LIKE A REGULAR RADIATOR WITH CAP?

 

[jhMalibu]

I had the cap on the overflow tank off. It went down as the rad was draining.

For fillup, I poured a gallon of antifreeze in the overflow, started the engine, went back to the engine bay, saw how little I had left in the tank, muttered some expletives and started pouring my second gallon in the tank as fast as I could till I reached MIN. Sealed the overflow.

I let the engine warm up and pressed gas to around 1800 to 2000 RPM for short periods while having the heat on high, confirming that the heater core was working fine and the thermostat was open. After shut down, I carefully opened the tank and added more as there is a bit of a drop in fluid level once you get the entire system flowing.

I did it this way because that is roughly what the Haynes or GM (can't remember) manual says to do for my Malibu. I just adapted the procedure to the Ranger because as far as I can tell, they are both sealed systems with the overflow tank being the high point. The sustained RPMs helps flush out air pockets. I'm sure someone else around here will point out the errors of my thinking/ways.

 

[doitmyself]

Thanks,

Unless someone else chimes in, it seems that I can treat this just like a system with radiator cap, only I will use the overflow cap to fill the system.

 

[901Memphis]

The overflow tank is also a degasser tank which means under normal conditions that it will purge itself of air if everything is working properly. Just make sure you don't have any cracks in the tank, the cap is holding pressure, and there are no leaks in the system and it will rid itself of all air over a short period of time. After my flush run i think there was very little air in the system based on the low amount of top off fluid i had to add within the next few days.

My 99 Taurus is pretty much the same setup though; no rad cap with overflow tank and rad drain petcock. Its all gravity drain as far as i can tell from doing it myself and before, so you want to leave the overflow cap off when draining the radiator petcock for speed and fully draining the radiator.

When i flushed my system it took about 9 gallons of distilled water which equaled about 5-6 fill ups then i started the car topped off the tank, put the overflow cap back on and ran the engine til warm with the heater on full blast.

After each time i allowed it to cool off and kept warming it up each cycle to fully distribute the distilled water throughout the system. I allowed short cool off time in between runs by using a box fan to blow under the car on the radiator so i could drop the coolant temp just enough to not get burned in between. I think i waited approx. 10 minutes for cool off period, but the longer the better.

On the last drain of distilled water i measured the amount of water i got out of the radiator (Trying not to spill any for accuracy!) and then based on my total system capacity (11.5 quarts) and how many quarts of distilled water drained from the radiator on the last try i knew how much pure antifreeze to add to the system to get a 50/50 mix. I am sure it will vary in your system but i didn't even get 6 quarts from the radiator so that tells you the rad holds less than half the capacity of fluids in the system.


Also i would like to add that i have a stubborn system and it gets corrosion very easily so the first thing i did days prior to any of this was drain all the old coolant and cycle with water a few times to get all the old antifreeze out then i used some Prestone Super Radiator flush which greatly helped clean the stubborn stuff out of my system gently.

I am not sure if you are plagued with the same problems as my Taurus but my system accumulates rust very easily due to a few reasons and i recommend that Prestone Super Rad Flush which you can leave in with pure water for a few days or longer provided it doesn't get below freezing.

 

[doitmyself]

Awesome! Thanks.

 

[mechanicx]

Originally Posted By: doitmyself
Thanks,

Unless someone else chimes in, it seems that I can treat this just like a system with radiator cap, only I will use the overflow cap to fill the system.


Yep you can consider the reservoir the same as a radiator and cap. It is the high point connected to the top of the radiator and normally the bottom hose. So as was mentioned it acts like it is the part of the radiator and will gravity drain.