Flushing Coolant

[TexasAggie09]

After doing lots of research and such, I will be removing my oil cooler this weekend to replace the leaking seals and I will be doing an oil change and coolant flush while I had it all drained. I think I will do a complete flush of my coolant and have decided to go ahead and fill it with the ELC. My questions are:

Can I use any EC-1 ELC or does it have to be that specific Cat brand? Where have yall gotten it?

Does anyone know a good place to get new plugs for the block once I take them out to drain?

Do I have to/Should I replce the t-stat? If so, which one?

Thanks yall

[TexasAggie09]

Anyone have any ideas?

[zROCK]

As far as i know you don't need to remove the plugs to do a coolant flush but i could be wrong. What worked best for me is i removed the rad and kept filling it with water blocking the bottom outlet and draining it until it ran clear. Their was a crap load of junk in the bottom of the rad. Then i put the rad back in and filled the system with water and ran until the thermostat opened and drained. Did this a few times until it ran clear

[madpogue]

I thought I read somewhere that we should NOT use ELC in the OBS. Of course you need the anti-cavitation.

Are you talking about the freeze plugs? Seems like a strange way to drain coolant, since they're nowhere near the bottom of the block, and they're meant to be permanent. Wouldn't the block drain simply by removing the lower radiator hose?

[jacobm24]

I know this was on a newer 7.3 but I thought it might help. I didn't take out the engine plugs. I just drained my radiator and refilled with distilled water only and ran down the highway and back and drained again. repeated about 5 or six times until I only got clear water coming out. for the last time I drained the radiator and refilled the whole radiator with coolant. I'm not sure about yours but the newer 7.3 holds 4 gallons in the engine and 4 in the radiator so that came out to a decent 50/50 mix. Whoop!

[TexasAggie09]

Thanks for the info guys. As far as the ELC, there are lots of threads with many pages of people debating ELC antifreeze vs. the green stuck with SCAs so I don't want to open that can up here. I just came to my own decision after reading for a few days.

On the drain plugs, I've read a few write-ups that say to remove the two drain plugs at the bottom rear of each side of the block. Doesn't seem like the freeze plugs to me but it could be I guess.

[madpogue]

I think the OP was referring to freeze plugs, since s/he mentioned replacing them. You certainly don't need to replace the drain plugs if you remove them.

[mymileager]

use a 203* diesel site t stat and ELC Coolant is ok for the 7.3L truck.. removing the plugs can vary depending on how your flushing the system, if your hooking it up to a garden hose then i would say remove them, if your just running several applications of water threw the system by driving then i would say pass on removing them, and also for replacement... only if the threads or head are bad then replace if not then i would say reuse but be sure to place some Teflon on the threads

[vegasjeep]

I had pics of the drain plugs, ill see if I can dig them up again for you.

as for flushing, i drained by removing the lower rad hose. I also pulled the thermostat out and replaced it. I ran the hose right in the thermostat housing and kept filling and flushing that way. I would leave the truck running and running cool water through it while it flushed out. When done I had crystal clear water and let it all drain the best way possible Refilled with distilled and antifreeze and was good to go.

[TexasAggie09]

Did any of yall have problems with the oil cooler clogging? Since I am changing oil and replacing the oil cooler gaskets and seals at the same time, I was planning on draining oil and coolant first, doing my thing on the oil cooler, then finish changing the oil then start flushing the coolant. What happens if the oil cooler clogs? How does one fix that?