93 Explorer, 20+ flushes in a 2 year old cooling system, coolant still brown | Ford Explorer Forums - Serious Explorations

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93 Explorer, 20+ flushes in a 2 year old cooling system, coolant still brown

MountainSAR994

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1993 Ford Explorer XL
I'm aghast at the prospect of needing to trash a perfectly good cooling system and re-rebuild after only two years of operation.

I have had the pleasure of driving a 93 Explorer for two and a half years. The previous owner neglected the cooling system, so the coolant it had was rust soup. Two months of flushing once every two days with distilled water and occasionally Prestone flush solution yielded nothing. I changed over to 50/50 green antifreeze at the onset of winter temperatures, and that apparently killed the radiator. I conceded and rebuilt the entire system: new radiator, water pump, thermostat, new heater core, and new hoses.

That was two years ago. The system has run with pristine, green antifreeze ever since. I've replaced the water pump once in that time. I was not surprised, as it was a remanufactured part. I recently drove round trip to Nevada from Idaho and covered over 800 miles. During that trip, my engine threatened to overheat - the cause was silicone gasket material blocking the air bleed valve in the thermostat. I ended up replacing the thermostat in Nevada, myself. The coolant was a horrible brown, and several flushes first with tap, and finishing with distilled water did not change the condition of the water, it was perpetually rust brown.

I drove home and started flushing. I initially used my garden hose to purge the radiator with the hoses detached, then ran the system with tap water up to temperature, then drained and used one flush of distilled water to purge the system of tap water, then added distilled water and Prestone flush solution to be run in the system for several days.

I've been doing this for a month. I've drained two loads of distilled water out of my system just today and they are equally brown. I've even pulled the upper and lower hoses and scrubbed the insides to remove residual brown and I've scrubbed out the overflow reservoir, to no effect. This is an endless tide of brown and there is no end in sight.

I have never had anyone here speak of flushing more than once or twice, yet I am in over 20 or 30 flushes and I have made no progress, and this is a system that was perfectly clean two months ago and was new out of the box two years ago. I would understand a 20 year old system could be this bad, or a neglected one, but mine was pristine.

When the system heats up, the water in the radiator, at the cap, changes from clean to brown within seconds after the thermostat starts to open. This isn't accumulation of rust over weeks, it's something in the water becoming agitated instantly, and re-accumulating in the presence of Prestone radiator flush and distilled water.

My only theory on this was the extended trip and the high temperature caused rust in the cast iron block to break free, but that should have gone away more than a dozen flushes ago. I've read into head gasket failure symptoms and they're just not present, there is no water contamination of the oil, no oil contamination in the water, and no white steam out of the exhaust.

I'm running out of ideas. Everything I've read so far is inapplicable, especially someone's comment on mixing or burning coolant - impossible because I'm running straight water and flush solvent. Every response seems to address a system that has never been flushed, or a system with an ancient cooling system, neither of which is applicable.

Has anyone else faced an endless tide of brown water coming out of a new cooling system and figured out what it is and how it finally gets resolved?
 



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When you say you've been flushing the system do you mean just the radiator or the whole engine block? The engine block itself holds a good bit of coolant and if you're not getting that it may just be turning the whole system brown again in no time. One time when I was changing a water pump and flushed out the block I was surprised at the amount of brown that came out of there. You might try sticking a hose in the water pump where the hose goes in, undoing the outflow hose from the engine and try flushing it out.
 






When I drain, I pull the heater hose so I drain every drop out of that system, and get about two gallons. I have not tried the flush with the continuous feed from the hose but I have not done that because I don't trust my garden hose to stay in position, and that would make a real mess. I've been recovering the flush.
 






Oxalic acid works, white vinegar, or cascade dishwasher detergent. The auto parts store coolant flushing products are about as strong as mouthwash these days.
 






try muriatic acid disable thermostat when running.
roscoe
 






I'd also do a pressure test.
 






You could try this as well.

upload_2017-8-30_2-46-49.jpeg
 






CLR is tough stuff. I do have a question about it -- would you cut it with water, or use it full-strength?
 






I'd pour the whole bottle in, top it off with water and let the engine idle for 20 minutes. Then flush it 2-3 more times with water to get the CLR out (defiantly don't want leave it in there as it's corrosive to aluminum) then fill up with your anti-freeze and call it good enough. All the rust is probably settled to the bottom (in the block) and will be hard remove. Only other thing I can think of would be to remove the water pump and stick a pressure washer nozzle in the water passages (the two holes that go to the waterpump, front of the block) and try to blow it out.
 






CLR will foam up like crazy, but it works good!
Use the flush attachment as recommended. without the pressure release it has in the fitting you could blow out gaskets because the hose pressure will be over 45PSI, so be careful with it's installation.
You need to power flush it out I see no way of containing it all.



After a good flush and fill, Test your coolant for electrolysis, your water pump impeller could be going away if it is occurring, or, possibly the heater core.

Put your positive meter lead into the coolant in the radiator cap hole, and the negative lead on ground. You should read very little in the millivolt range. Any more than 10 milivolts is a concern.

Possibly ground straps missing?
 






I'm disappointed. The suggestions I get are damage my system with CLR, damage my system with muriatic acid, test if my new water pump is new, and use vinegar, which is something I've tried before, I tried again last week, and it has repeatedly disappointed with lack of efficacy. I'm done with this forum, goodbye.
 






I'm disappointed. The suggestions I get are damage my system with CLR, damage my system with muriatic acid, test if my new water pump is new, and use vinegar, which is something I've tried before, I tried again last week, and it has repeatedly disappointed with lack of efficacy. I'm done with this forum, goodbye.
Well, I damaged the cooling system of my 93 aerostar with half a bottle of CLR when I first got it , of course it got flushed out real good afterward.
I didn't do a thing to the coolant other than change it for the 140k miles we owned it. a deer finally killed the van. One power steering hose, one alternator and an 02 sensor and 2 sets of tires are the only parts it ever used.

So, to say we gave intentional bad advice is kinda being harsh. It's not our fault your truck is being a hooptie.

I assumed the traditional flushing wasn't working, so something a bit more robust, for a short time and flushed right out, would not hurt a thing. Good luck.
 






I'm not sure what you want, a magic solution? There is a huge wealth of information on this forum. You clearly have a very nasty engine block which is going to take extreme measures to correct. A short amount of time with CLR likely won't damage anything. I suppose you could flush it another 100 times without results.
 






CLR works fine and I've heard of it being used and vehicles running great for many, many years afterwards. If it isn't left in too long and the system is flushed clean afterward, with a new thermostat installed, it'll likely be fine.

Rustoleum also has some rust remover similar to Evaporust, that says on the back label that it's safe to use in automotive cooling systems.

http://www.autozone.com/paint-and-b...-thinner/rust-oleum-rust-dissolver/591721_0_0

http://www.autozone.com/paint-and-b...-thinner/rust-oleum-rust-dissolver/591720_0_0


It sounds like you were going overboard with the constant water use and flushing that way, instead of just hooking up a hose and flushing by running the engine until the water was clear, then using a rust remover, driving with that for a short while, then flushing with a hose and the engine running again, and maybe even repeating the cleaner use once or twice more.

You can also use nylon stockings as a net at the radiator intake (upper hose inlet on the radiator) to catch any solid particles that would otherwise clog the drain or get stuck in the system. Sometimes using those a few times with the rust cleaner really does the trick since it's those big rust chunks that cause a lot of the brown color in the flush. Once those are removed the cleaner can just clean the engine and cooling components and there's really nothing left to discolor the water as long as the water/cleaner mix isn't allowed to stay in the block/heads too long, and a fresh 50/50 water/coolant mix will do it's job and prevent rust and corrosion.
 












CLR is an Acid with a PH of about 2.7, most commercially produced Vinegar has a PH of 2.4 and the Prestone Radiator Flush is an Alkalyne with a PH in the area of 9.2 or so. If you used Vinegar, then from an Acid (PH) perspective, then CLR will do nothing for you. muriatic acid would work on the engine block if you bypassed the radiator, heater core and used a pump to circulate only through the engine. Just keep flushing the system the way you have been and hope for a different result each time....
 






See ya!!!!..........
But note that it's a 93 iron block. You could flush it till you drain a small lake & still not get it green. Mine is brown, & change it every 2 years & live in summer all year long & I never had a cooling problem.
 






I don't think you've got bad advice, CLR is probably the best thing to use. It is corrosive to aluminum, but so is anything that is going to eat rust. Run it for just a short time as was suggested, and drain. Then make sure you flush it out good with water.
 






The OP is frustrated. He'll do better without us.
N O T .
 



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a mechanic at a shop told me i needed to change out the timing cover since the gasket is leaking, the cover is corroded and thats what keeps my fluid murky brown even after flushing
 






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