Is there a straight forward method of changing the coolant in a 2000 4.6? I wanted to be sure that all of the old was removed before adding new coolant and am guessing that simply opening the radiator drain will leave old coolant in the block and heater core. I am at about 50,000 miles and use the regular green coolant. Is this the time to change my thermostat as well?? Thanks

 

You can unscrew the block drain plug on the driver's side, it's easy to get to on a 4.6L, at least on a 2WD truck. Look for the line of big freeze plugs, and you'll see the block drain plug along there towards the back. I got at least another 3 Quarts out by pulling it. It has a pipe thread to it, so just use some antifreeze compatible Permatex sealer on the threads when putting it back in. There is a plug on the passenger side too, but the starter blocks it, and I didn't feel like pulling the starter. I'd leave the thermostat be.

I like to put in the Prestone Flush-n-Fill tee in the heater hose, and use a garden hose to flush. But there are less and less vehicles I can do that with nowdays, no good straight run of heater hose to put it into. I'm not comfortable putting a plastic tee into a short or curving heater hose, or one that flexes a lot with engine movement. So I didn't use on on my '97 4.6

 

Torky 2

Thanks for the help. Should I drain then fill and run with water and a special flush liquid, or just drain and refill? It sounds like there is no way to get ALL of the old stuff out (heater core etc.).

 

I just used water, no cleaner. If it was an old car, then I probably would have used some cleaner.

With radiator cap off, radiator drain open, and driver's side block plug out, I think the only place left for coolant to hide is in way down in the block, passengers side, low down by the freeze plugs. Pulling the drivers side block drain will drain everywhere else, including the heater core. I'm pretty sure the heater core empties out using this method.
BTW, I measured out what I drained out, came up just a Quart or two short of total system amount. Figured it was in the passenger side block low down.

With cap off, radiator drain open, and block plug out, after it stopped draining, I flushed water through the radiator neck (well, actually its the combination radiator cap holder and storage tank ) and let it run out both opens. Then I closed the radiator drain, and continued to flush it out the block drain. Then I put the block drain back in (no sealer, just temporary this time), and filled it up with water slowly. Then ran engine till upper radiator hose was pressurized and hot (thermostat open). Then let it cool for a hour or two, and opened it all up again and let it drain.

Then I put sealer on the block drain, and put it in. Closed radiator drain. Then filled with required A/F amount (1/2 of system capacity), then slowly filled the rest with water. For the next few days, I checked the tank level, as it continues to burp out some air for a bit.

Pretty easy all in all. I should probably do it again some time

 

Torky2


Thanks for the detailed directions. This is my weekend project!!

 

You're welcome!

Uh, can you come over and do mine again sometime? hee hee