So.... It's the day after a tech day at Fat Diesel's Mantown where I spend the better part of the day performing a coolant flush on my 190k Excursion. The water pump had already been replaced by the PO's mechanic. I read Gooch's tips and Stewart's write-up and had Stewart helping me most of the day. Figured I'd post up my experiences for the sake of sharing info.
First some tips.
0. Keep your dogs and cats away from the repair site. Antifreeze is poisonous and they will try and drink it.
1. The kiddie pool idea is brilliant. I should of taken that tip more seriously. I only had 2 5 gallon catch pans and made a big mess.
2. If you don't have a kiddie pool, try and have enough containers to catch and store the first two flushes of antifreeze for recycling. Those will have the most amount of poison in them. After that, the mix is pretty diluted.
3. Expect to get soaked. If you are not doing this in the privacy and comfort of you own home, pack a change of clothes - including underwear, socks and shoes.
4. If you are doing this over dirt, plan on moving the truck once or twice. Unless you like rolling around in mud. I didn't expect to make as big of a mess as I did so I started in dirt...
5. If you have a higher mileage motor, 20 gallons of distilled / 2-3 flushing cycles with distilled may not be enough. I needed 40 gallons and probably 6+ flushing cycles. So have a helper around to go get extra water (Thanks Reno!!) or budget time into your schedule to go get it yourself.
6. The rear-most bolt on the thermostat housing is difficult to reach and you may drop the bolt. I did. Twice. We couldn't find either bolt... Have a spare (or three) on hand. Consider replacing that housing with Riff Raff Diesel's 7.3 billet aluminum thermostat housing
(no rust) - Riffraff Diesel: NLTD 7.3L Thermostat Housing
Now some comments on the process itself.
1. The back flush procedure
The back flush procedure using hose water didn't do much for me. We hooked up the flush kit and hooked up the hose and ran the truck through 2 flushes. I never really saw much of anything particularly dirty coming up through the degas bottle. This wound up being a huge surprise when I did the first flush using distilled. The water that got dumped from the radiator and block on the first flush with distilled was a dark doo-doo brown and pretty thick with sediment. I would have gotten a pic but see tip #3 and #4 above.
I think the reason why this happened is a potential fault with the back flush logic itself. The cooling system was designed to run in a certain path flow. In one end of the rad, out the other through the heater core and back to the rad. When you insert the T into the heater core hose, the direction of the water coming from the garden hose goes both ways - to the block and to the heater core. The flow from the heater core may not be counteracted by the pressure of the water coming our of the garden hose which may prevent all the crap from the heater core from actually making it past the garden hose and out to the radiator.
This explains why my first flush w/ distilled w/o the garden hose was dark brown.
2. Drain using the hoses not the radiator drain valve
My head of the radiator drain valve on my radiator had been broken off by the PO so I decided to pull the 2 lower radiator hoses on the passenger side of the radiator to drain fluids. It was a lot easier than trying to screw with the drain valve.
What I observed when draining using the radiator hoses was that the smaller diameter hose dumped out the nastiest looking water. I assume that hose had a more direct path back from heater core or whatever the dirtiest part of the engine block is. I consistently got dirtier water/coolant when draining from that hose compared to the lower radiator hose.
3. Idle time during the flush
I noticed that the best flushes that resulted in the dirtiest water dumps required that the engine idled for at least 4 minutes. I didn't go beyond 6 minutes of idle time on any of the flushes. If it idled less than 4 minutes, the water that was dumped out didn't look too bad. When I started watching how long the truck idled and monitoring the murkiness / dirtiness of the water returned to the degas bottle, I noticed a correlation between time spent idling and thoroughness of water circulating during the flush cycle and by extension the amount of crap getting dumped out of the engine and heater core back into the radiator.
4. Disconnect the batteries
One of the steps in the flush procedure is to remove the drain plugs on the block. The drain bolt on the passenger side is directly above the starter. The starter has a hot lead from the battery. Touch the starter with wet hands and metal tool and you'll be shocked. I made this mistake twice...
5. Step by step for draining
Building upon the above tip on disconnecting the battery, I found it helpful to have a repeatable process so I wouldn't shock myself again...
So the steps/process involved in draining will go something like this:
after engine has idled with distilled...
- turn off the engine
- disconnect the batteries
- remove the 2 lower radiator hoses, allowing to drain
- remove the block drain plugs, allowing to drain
- reconnect the hoses
- re-install the block drain plugs
- fill with ~7 gallons of distilled
- reconnect the batteries
- run engine for 4-6 minutes w/heater on high
That is all I can think of right now.
The only other tip I can share is with regards to sourcing the ELC. I wasted a few hours trying to find any of the recommended ELC coolant in concentrated form. I live in metro area so no truck stops or International dealers around me. I couldn't find a dealer close enough that was open on weekends and couldn't find it available online that could ship it to me at a reasonable cost and still make the date.
By sheer dumb luck I found that a local O'Riely's auto parts had 2 gallons of Peak Final Charge. The Peak brand seems to be the only brand of ELC coolants that auto parts stores carry. Turns out that they can special order the stuff even though they don't normally have it on the shelves. Maybe some of you know this already but it was my first time trying to find this stuff and it was a big friggin' pita and cost me time.
Hoping someone else can learn from my mistakes here.
In summary, this was hard work. My body hurts a lot today from all the up and down of the day. I probably spent 6-8 hours on this. The coolant was positively nasty and I know for a fact that there isn't a mechanic out there that I could have paid to do this job as thoroughly as we did. There is no performance gain out of this but I just ensured that my cooling system will be reliable and extended the life of the engine.
Special thanks to Andy, Stewart, Reno and David for all the help and support on this project.