^^^^^ Note that the clip is for the CORD for the block heater. The heater element itself is threaded in; doesn't just pull out.

We have two PSDs and one IDI, and it's a mish-mash of block drain plug types. Some square hole, some hex bolt, IIRC at least one square bolt. By this time in the lifetimes of our trucks, most likely one/both have been replaced, and it's a generic plug, and of course if both were removed for a drain/flush/fill, they could have been swapped. Be prepared for anything.

I remove the starter, but I don't disconnect the wires. There's enough wire to allow you to swing it around 180 and set it on top of the TTB arm (if so equipped). Never had a starting problem afterward.

Hmm, I wonder if the block heater might be a bit lower than the drain, and might allow a little more of the old stuff to be drained out. Similarly, for the radiator, it's good to remove the lower rad hose after dong the rad drain each cycle of the flush, since the hose is lower than the drain.

 

Yeah they are pretty hard to take off, normally I just heat them up with a propane torch and they come off. But I like glenns Idea better.

 

Typically pulling the block heater with a quick post flush will get almost all of it out.

You mention the truck runs hotter than it used to after the flush? Might want to take a look at the thermostat as well then. There are different opinion on thermostats on these trucks, but if you plan to pull heavy I'd suggest getting a Terminator 180 thermostat from riffraff diesel Terminator 180ºF Thermostat - Riffraff Diesel Performance

Stock its a 192-195. They make a 203 as well. In all honesty the 180 keeps the truck running right around N with no load. O to M when pulling hard with a big load. The OE unit either was defective from the factory or simply wasn't the right combo for heavy towing as I went through two of them and the truck would push past L on the dash gauge. The 180 did the trick, never went past M pulling twice as much.

I have never tried or considered a 203. This was all post OE new water pump install. I thought I had a plugged radiator for a while. During the winter it heats up and the air is just as hot as it was with the OE thermo in there when it -20 out.

The dash gauge some call a dummy gauge. Yes its not numerical correct for an exact number, but its not worthless either. If one is running hot on that gauge(above m) unloaded.... the truck is not cooling properly.

 

I hate trying to unscrew old, rusted-in plugs from an old block and removing the starter in the process. So I just drain the radiator and put in the proper formula of distilled water, new green coolant and DCA4 every three years or so.


To catch any debris that might be in the cooling system, I also have a bypass filter installed in the heater hoses and change it with the coolant.


If I feel guilty about leaving maybe a third of the old coolant in during any given coolant change, I flush out the system with distilled water for two or three heat cycles before putting in the proper amount of antifreeze and DCA4, then topping off with distilled water. If I feel really, really guilty, I use a radiator flush treatment for the first heat cycle.


This process has been working OK since I bought the truck in 1996. My OEM radiator just began leaking a little bit a few weeks ago after 20 years of service, so I replaced it. I had to replace the water pump a couple of years earlier.


Everything looks good and clean in the system. No rust or corrosion evident anywhere. Steady as she goes for the future.

 

I mentioned earlier in this thread running into a no start issue during the coolant change process. Just wanted to follow up briefly. Hate to post a problem and then not comment on how it was solved.

So the problem was a no start, no crank, single click issue. Did normal troubleshooting - checked to ensure batteries were charged, battery terminal connections were tight, grounds were clean and secure, power was getting to starter relay on RF fender, removed starter and tested it. Truck would start after sitting a day or so. Would get this problem during draining and flushing process. Got a little frustrating. Once the coolant change was done I had the issue after driving in the rain.

Pretty sure the problem was the small ignition switch wire that goes from the relay on the RF fender down to the starter solenoid. Found these cracks in the wire.




Taped up cracks, truck is starting fine now, knock on wood.

Regarding the original question about how much drains and how much goes back in, I think I got about 3-4 gallons out of the radiator and about a 1-1.5 out of each side of the block. When refilling, it took about 6 gallons, 4 antifreeze and 2 distilled water, topping off periodically to get it close to 8 gallons full.

 

Good find, glad for you its running again. Thanks for reporting back.