Flushing cooling system with citric acid?

[GG-1]

Hello All!

Sorry guys, tried to delete this post since I realized there was a cooling/heating/A/C Forum and also posted there.. can't figure out how to delete this one though.

Im hoping some of you could share your experience flushing the radiator and block with a citric acid solution. The 383 in my 1967 Fury(GG) is still excreting brown water even after several flushes with just water, and one with a flush product added.
My radiator flushes clear by itself, but when it circulates through the block the water is still coming out brownish. I was told that the radiator was re-cored when I bought her 2 1/2 years ago.. but it seems like maybe a lot of stop leak may have been added at some point.. IDK for sure.. but the engine did sit for several decades without coolant changes. There are no signs of coolant leaks, internally or externally... and I don't want to create any! I've read conflicting accounts on the interwebs about citric acid. The standard protocol seems to first "degrease" the passages with a Dawn or Shout flush, drain, then a citric acid solution of 1 lb of citric acid dissolved in a gallon water, into the radiator, then fill the rest with water, and run/drive car for 15-30 minutes. Some say drive it longer, then flush. A few out there claimed this weakens water pump gaskets, etc. and caused leaks. Many others say it works great. So I ask you kind C-fellows-- any advice/ testimonials?
Thanks, Alex

ps. Also, where do I get an adapter tee/flush kit for garden hose attachment to the upper radiator hose. I want to run water in through the water pump housing(snugly fit) to pressure flush the block.

 

[Davea Lux]

Hello All!

Sorry guys, tried to delete this post since I realized there was a cooling/heating/A/C Forum and also posted there.. can't figure out how to delete this one though.

Im hoping some of you could share your experience flushing the radiator and block with a citric acid solution. The 383 in my 1967 Fury(GG) is still excreting brown water even after several flushes with just water, and one with a flush product added.
My radiator flushes clear by itself, but when it circulates through the block the water is still coming out brownish. I was told that the radiator was re-cored when I bought her 2 1/2 years ago.. but it seems like maybe a lot of stop leak may have been added at some point.. IDK for sure.. but the engine did sit for several decades without coolant changes. There are no signs of coolant leaks, internally or externally... and I don't want to create any! I've read conflicting accounts on the interwebs about citric acid. The standard protocol seems to first "degrease" the passages with a Dawn or Shout flush, drain, then a citric acid solution of 1 lb of citric acid dissolved in a gallon water, into the radiator, then fill the rest with water, and run/drive car for 15-30 minutes. Some say drive it longer, then flush. A few out there claimed this weakens water pump gaskets, etc. and caused leaks. Many others say it works great. So I ask you kind C-fellows-- any advice/ testimonials?
Thanks, Alex

ps. Also, where do I get an adapter tee/flush kit for garden hose attachment to the upper radiator hose. I want to run water in through the water pump housing(snugly fit) to pressure flush the block.

Your local auto parts should have the tee for the flush kit. Putting any kind of acid in a cooling system is a bad idea, your coolant going acidic is what probably caused the system to rust up in the first place. It should not be necessary to "degrease" your cooling system unless you have had an ATF leak into the cooling system from a faulty transmission cooler. Also keep in mind that tap water, if you live in the city, likely contains Chlorine and possibly Fluoride, both of which are highly corrosive and should not be left in a cooling system. Cooling systems are best flushed with distilled water. Many flush products come with a neutralizer, be sure to use it and then drain all of it out and flush the system. You have succeeded in breaking loose years worth of degraded antifreeze and rust and there is no quick fix. I would flush again and add a two-thirds mixture of fresh antifreeze, the rust inhibitors and corrosion inhibitors in the antifreeze will stabilize your cooling system. I would run this and keep an eye on how the coolant looks after a couple of months. If necessary, drain and refill again with fresh antifreeze.

Dave

 

[GG-1]

Your local auto parts should have the tee for the flush kit. Putting any kind of acid in a cooling system is a bad idea, your coolant going acidic is what probably caused the system to rust up in the first place. It should not be necessary to "degrease" your cooling system unless you have had an ATF leak into the cooling system from a faulty transmission cooler. Also keep in mind that tap water, if you live in the city, likely contains Chlorine and possibly Fluoride, both of which are highly corrosive and should not be left in a cooling system. Cooling systems are best flushed with distilled water. Many flush products come with a neutralizer, be sure to use it and then drain all of it out and flush the system. You have succeeded in breaking loose years worth of degraded antifreeze and rust and there is no quick fix. I would flush again and add a two-thirds mixture of fresh antifreeze, the rust inhibitors and corrosion inhibitors in the antifreeze will stabilize your cooling system. I would run this and keep an eye on how the coolant looks after a couple of months. If necessary, drain and refill again with fresh antifreeze.

Dave

Ok great, Thank you Dave.
I'll surely find the flush kit.
And you're right, there is no reason to degrease the system.
After the last flush I filled system with 50/50 antifreeze.
I live in NYC, but the car is an hour north of here.. still, the water is probably chlorinated and fluoridated.
I've heard Cascade is good for flushing and is dishwasher safe.. acidic? IDK.

I'll get the adapter and some patience and attempt to run water through both ways in hopes of it turning clear... then as you said, refill with a 2/3 antifreeze mix.

 

[Davea Lux]

Ok great, Thank you Dave.
I'll surely find the flush kit.
And you're right, there is no reason to degrease the system.
After the last flush I filled system with 50/50 antifreeze.
I live in NYC, but the car is an hour north of here.. still, the water is probably chlorinated and fluoridated.
I've heard Cascade is good for flushing and is dishwasher safe.. acidic? IDK.

I'll get the adapter and some patience and attempt to run water through both ways in hopes of it turning clear... then as you said, refill with a 2/3 antifreeze mix.

Cascade is a mild base, will help get rid of any residual acid. Be sure to remove the T-stat when flushing, might be a good time to replace it if it is old.

Dave

 

[Davea Lux]

Cascade is a mild base, will help get rid of any residual acid. Be sure to remove the T-stat when flushing, might be a good time to replace it if it is old.

Dave

When you get ready to put antifreeze back into it, be sure to use Ethylene Glycol type anti freeze. The more modern Propylene Glycol, or green antifreeze in not appropriate for this era engine.

Dave

 

[GG-1]

Cascade is a mild base, will help get rid of any residual acid. Be sure to remove the T-stat when flushing, might be a good time to replace it if it is old.

Dave

Ok, how much cascade powder per flush?

 

[GG-1]

When you get ready to put antifreeze back into it, be sure to use Ethylene Glycol type anti freeze. The more modern Propylene Glycol, or green antifreeze in not appropriate for this era engine.

Dave

Why, what happens with green? I've been using green Prestone 50/50 since I got the car.

 

[GG-1]

I've been using green Prestone 50/50 since I got the car.

 

[Davea Lux]

Why, what happens with green? I've been using green Prestone 50/50 since I got the car.

"Green" as in Al Gore enviornmental wacko, not green the color. The "earth friendly" antifreeze is usually pink in color. Green or yellow coloring will be Ethylene Glycol in either standard(green) or long life (yellow).
You have already put a flush product in you system, you probably do not need to do it again with Cascade as both are likely very similar in composition. To answer you question, about one tablespoon of powder per gallon of cooling system capacity and try to dissolve it as much as possible before putting it into the cooling system. Drive the car for 20 miles or so and drain it out. Flush the system twice afterwards. Cascade has some abrasive in it to get your dishes shiny clean and you want to get rid of all that.

Dave