Safe to use oxalic acid in Ford 4.6?

[Twisted1]

Hey all. Wondering if it would be safe to run oxalic acid with distilled water in my 2001 Ford 4.6? I’ve flushed the coolant per interval with Motorcraft coolant but the last 2 times the system seemed rusty.. Is that the best method or any other suggestions? Google doesn’t come up with much so I thought I’d come here and ask.

 

[joegreen]

I use the Mercedes’ citric acid flush. I would look that up. It’s a Mercedes’ factory certified way to clean out the cooling system.

 

[Falcon_LS]

Get yourself 2 lbs of citric acid powder from the grocery store and dissolve it in 1.5 gallons of warm water.

Drain your radiator, pull out your thermostat and with the lower radiator hose disconnected, back flush the system through the thermostat housing with water until it runs clean.

With the radiator cap off, pull the heater core hose off the intake manifold near the firewall, reconnect the lower radiator hose and fill the system with 1.5 gallon citric acid powder solution, topping off with water as necessary. Once it overflows, reconnect the heater hose and keep filling the system until it is full. Replace the thermostat, tighten the housing and start the engine.

With the heater on, run engine for 15 minutes at 2,500 RPM and blip throttle occasionally. Once this is done, allow take the petcock off the radiator and let it drain until it stops. Take the radiator cap off and allow it to drain some more before pulling the thermostat out again and thoroughly backflush the system with a hose until it runs crystal clear.

Refill the system, as described previously, with distilled water this time. Start the engine and run it at 2,500 RPM for 5-10 minutes to flush all cleaning solution from system before repeating the drain procedure described previously. You may need to repeat this process, depending on how the water flows out the radiator. But once it runs clear, refill with your coolant of choice and replace the thermostat and the o-ring. Make sure you "burp" the system afterwards.

 

[Trav]

Citric acid only in mixed metal engines or cooling systems.

 

[Twisted1]

Get yourself 2 lbs of citric acid powder from the grocery store and dissolve it in 1.5 gallons of warm water.

Drain your radiator, pull out your thermostat and with the lower radiator hose disconnected, back flush the system through the thermostat housing with water until it runs clean.

With the radiator cap off, pull the heater core hose off the intake manifold near the firewall, reconnect the lower radiator hose and fill the system with 1.5 gallon citric acid powder solution, topping off with water as necessary. Once it overflows, reconnect the heater hose and keep filling the system until it is full. Replace the thermostat, tighten the housing and start the engine.

With the heater on, run engine for 15 minutes at 2,500 RPM and blip throttle occasionally. Once this is done, allow take the petcock off the radiator and let it drain until it stops. Take the radiator cap off and allow it to drain some more before pulling the thermostat out again and thoroughly backflush the system with a hose until it runs crystal clear.

Refill the system, as described previously, with distilled water this time. Start the engine and run it at 2,500 RPM for 5-10 minutes to flush all cleaning solution from system before repeating the drain procedure described previously. You may need to repeat this process, depending on how the water flows out the radiator. But once it runs clear, refill with your coolant of choice and replace the thermostat and the o-ring. Make sure you "burp" the system afterwards.

Thank you! My only concern is would I be introducing any new issues by doing this i.e. issues to the radiator (brand new), water pump etc.?

 

[Twisted1]

Citric acid only in mixed metal engines or cooling systems.

My 4.6 2V had an iron block and aluminum heads

 

[Twisted1]

I use the Mercedes’ citric acid flush. I would look that up. It’s a Mercedes’ factory certified way to clean out the cooling system.

Thank you!

 

[LowMilesLesabre]

Citric acid only in mixed metal engines or cooling systems.

Get yourself 2 lbs of citric acid powder from the grocery store and dissolve it in 1.5 gallons of warm water.

Drain your radiator, pull out your thermostat and with the lower radiator hose disconnected, back flush the system through the thermostat housing with water until it runs clean.

With the radiator cap off, pull the heater core hose off the intake manifold near the firewall, reconnect the lower radiator hose and fill the system with 1.5 gallon citric acid powder solution, topping off with water as necessary. Once it overflows, reconnect the heater hose and keep filling the system until it is full. Replace the thermostat, tighten the housing and start the engine.

With the heater on, run engine for 15 minutes at 2,500 RPM and blip throttle occasionally. Once this is done, allow take the petcock off the radiator and let it drain until it stops. Take the radiator cap off and allow it to drain some more before pulling the thermostat out again and thoroughly backflush the system with a hose until it runs crystal clear.

Refill the system, as described previously, with distilled water this time. Start the engine and run it at 2,500 RPM for 5-10 minutes to flush all cleaning solution from system before repeating the drain procedure described previously. You may need to repeat this process, depending on how the water flows out the radiator. But once it runs clear, refill with your coolant of choice and replace the thermostat and the o-ring. Make sure you "burp" the system afterwards.

Very often, the citric acid in the grocery store that he is referring to can often be found in the section or aisle where they keep canning supplies.

 

[joegreen]

I like to get my citric acid on ebay. Last time i bought it it was a better price than the store.

 

[nthach]

You used to be able to buy citric acid at Whole Foods in bulk. Not anymore, I get that off Amazon.

Citric acid, after an detergent cycle using dishwasher detergent(ideally phosphated Cascade fryer boil-out but if not, any dishwasher pod works) would be the way to go. Oxalic acid is aggressive and fine for all-iron engines - hence why GM recommended Prestone’s old acidic cleaner for Dex-sludge on the 3.1/3.4/3.8/4.3/5.7L engines.

 

[michaelluscher]

Oxalic acid is aggressive and fine for all-iron engines - hence why GM recommended Prestone’s old acidic cleaner for Dex-sludge on the 3.1/3.4/3.8/4.3/5.7L engines.

3100/3400
They had to make a training video to absolve Dexcool and their overflow bottle design of cooling system woes on the early 2000s pig iron they were peddling
Fill it to the hot mark cold, that'll make up for shoddy engineering


To the OP, I'd pull the thermostat, and drive around with straight water + a few bottles of the cheap Prestone citric acid coolant flush
You can get a case on Amazon delivered
I did that to my late Taurus, made the already clean Iron anchor 3.0 Vulcan spotless

 

[Trav]

Citric Acid | eBay

Citric acid is one of the most common food additives in the world, used to boost acidity, enhance flavor, and preserve ingredients. Taste and Aroma: No aroma, but taste is slightly sour. Finally, citric acid is often used as a neutralizing agent and conditioner.

www.ebay.com