Changing coolant on my 2004 4.7 2wd. Radiator draincock only drains less than a gallon, even with the rear of the truck elevated, but capacity is 17 qts. Any ideas on draining the majority of the old coolant? Hate to resort to trying to remove engine block plugs. Thanks!

 

Did you check to see if it was low to begin with? Pull bottom radiator hose from block. This is is where the thermostat resides, so good opportunity if you want to replace it. You can also fill, drive and drain again to increase percentage.

 

The thermostat (and coolant) is original, so I think that's a great idea. I'll try that. Not worried about every last drop draining, but if I can get most of it I'll be good. Thanks!

 

Pay attention to thermostat orientation before you remove it. It can be easy to forget. Also, don't crank too hard on the thermostat housing bolts as they don't need much torque. I've seen guys break em.

 

Did you have the heater control to "Hot"? The core and hoses can hold quite a bit.

 

I've always removed the lower hose, then removed the upper hose and blew through it to remove any pockets of coolant trapped, usually isn't much. Seems good enough unless your coolant is mud then maybe do a more thorough job.
Once you rack up enough miles you'll never have to perform regular coolant changes again.
Something fails often enough where you end up changing it during the repair

 

Thanks everyone for the good tips. Removing the thermostat got another half gallon out. Haven't tried having the temp set to hot, that very well may get some out of the heater core. Coolant was original and was full when I started. Looks clean like new, but it's 16 years old. (This is a 70,000 mile truck.)
Now for the bad news. I broke the lower thermostat housing bolt taking it out. I was working it back and forth, as it was obviously corroded in there, but I guess I got a little too rough. I should have known better, I've been repairing my own vehicles for 30+ years. Should have put some heat in it. Oh, well. I guess now I'm removing the whole timing cover to repair or replace.

 

Can you drill out the part that's still in there? I would hope there is a chance of getting out the rest of the bolt before dismantling the entire front of your engine.

 

Unfortunately, I think it'll have to come out. There's just no way to see what I'm doing with it on the engine. It'll be tedious, even on a work bench.

 

I mentioned it, but should have stressed the multiple drain and fills. It's always the least troublesome and least risky method. I never mess with freeze plugs or disconnecting anything unless absolutely necessary. Also, the heater being on hot makes no difference. There is no heater valves in these trucks, so the core drains regardless.