Replacing coolant in 2003 V-6

[zoomie66]

Has anyone replaced the coolant in a 2003 V-6 themselves? My 2003 4Runner just turned over 30k so I bought the premixed pink Toyota coolant (yeah, the stuff with the "unobtanium" in it!) and tried to replace the coolant this weekend. According to the owner's manual the coolant capacity of the V-6 is 9.8 quarts, or slightly over 2 gallons (U.S.). I removed the sheetmetal guard under the radiator and opened the radiator drain, but after an hour+ only a little more than a gallon had drained out. I filled the radiator with a gallon of distilled water and ran the engine until it reached the normal temp range, then opened the drain again. Same thing...a little over a gallon drained out. I did this twice more, all with the same results. Each time I ran the engine up to the normal operating temp so the thermostat should have opened; should I have just removed the thermostat for the coolant replacement?
Obviously there must be one or more additional drains that I couldn't locate; what's the secret to draining all the old coolant out? I've owned and worked on Toyotas since 1981 and I never encountered this problem before. Help!!

 

[Jeff Kleb]

Flush it if you want......but that can be time-consuming and difficult.

When I did a drain/fill on my girlfriend's Highlander, it took awhile to get it right. There's a lot of coolant in the engine block, as well as what is in the radiator.

 

[GSGALLANT]

If I'm not mistaken, your 2003 4Runner V6 would be the 4.0L, right? Although it's not the same, on my 2002 3.4L 4Runner, there is an engine block drain on the passenger side of the block. However, if you set it up right on the 3.4L, you can drain all but about 0.5 quarts from the bottom of the radiator (same system capacity as yours - about 9.5 quarts). Once that's out, the last 0.5 quart can be drained out from the block drain.

Before starting to drain your system, be sure to select all your heater controls to hot. (I have front and rear heaters, and both controls should be set to hot), then remove your rad cap (It will drain a lot faster and more thoroughly this way. Finally, open the drain on your radiator.

Sorry I can't give you specifics on the 4.0L, though.
Good luck.

 

[zoomie66]

The 2003 V-6 is the 4.0L engine, and I'm fairly sure there must be at least one drain on the block somewhere...but I couldn't find it. Anyone have either a CD of or a hardcopy factory manual with a diagram of the 2003 4.0L V-6 engine which shows whether or not this block has coolant drains, and if so, where they are located?

 

[jeober]

I remember a discussion on this forum (I think) describing drain plugs on either side of the block accessible through each wheel well.

On the otherhand I could be losing my mind...

 

[PolkManiac]

Yeah, someone's done this before and posted instructions. I think there's two drain plugs in the engine itself - just search around and you'll find the thread...