[66RagTop]

Any suggestions on best practices to remove rust from cooling system? In process of installing new radiator but would like to clean out the block of any rust prior to the install. What products would you recommend to flush the system?

 

[awhtx]

Citric Acid flush.

https://www.google.com/search?q=citric+acid+flush&ie=utf-8&oe=utf-8

 

[Fordguy65]

I've been fighting this problem myself. I've flushed and flushed but the rust always comes back. Haven't tried the citric flush though...

 

[StangStang]

Man, that looks familiar. I just pulled the motor out of my 1967 Stang that I am restoring. The radiator was full of rust, water pump was packed with it and was very noticeable when rotated by hand. When I took the motor apart and knocked the block plugs out, flakes of rust fell out. I ended up building my own electrolysis setup in a big black container that the block could sit in. I made a hollow square out of wood to go around the perimeter of the block on top of the container and then mounted metal plates (6) that went down into the tub and not touch the motor. I connected all the plates with wiring on top. I filled the tub with water and Washing Soda (walmart) and connected a battery charger (negative on the block, positive on the plates). It sat for a week like this and the tank filled with rust on the plates. I pulled the block out and power washed it. It is like new now, even around the cylinders.

Of course you would only do this if you plan on pulling the engine... I know a lot of the guys with old cars and this problem will replace the radiator and install a filter inline between the return hose to the radiator and the radiator itself to prevent it from clogging up again. A good flushing will help.

 

[turbo2256b]

mORE LIKELY its old anti freeze over time it turns to a rusty looking muddy substance.

 

[1969sag]

On my Mustang and Ranchero.
I drained the cooling system. Properly disposing of the all of the old coolant. I then flushed the system with water until it was a clear as possible. I then used about 3 gallons of Evapo-Rust. I ran the cars that way for about 3-5 days.
Then I drained the cooling system. Flushed it with water, and I put in all new coolant.
I have not had one spec of rust in my cooling system for a few years now.
The evapo-rust removes all the rust from your system, it does not hurt any seals, sealant, or gaskets.
I am also a BIG supporter of using PROPYLENE GLYCOL for cooling systems. I am no super tree huger.
BUT. If you folks only knew how much ethylene glycol anti freeze poisons our environment for years, and years, and years. How it poisons our water table. You too would not use it. Every time a car accident happens, an a$$ dumps it where ever, every crappy junk yard, this poison enters out environment and it does not disperse, dissolve, or breakdown for YEARS ans YEARS.
The auto industry uses it because it is cheaper.
Please look into it and inform yourselves. This hobby could make a real difference.
I suggest Peak Sierra Antifreeze, or the BE-COOL antifreeze is also great.
I run the BE-COOL in my cars, that are not under specific manufacture warranty.
Hope this helps.

 

[Fordguy65]

mORE LIKELY its old anti freeze over time it turns to a rusty looking muddy substance.

This was a few months after flushing and cleaning. I even took it to an oil change place for a "power flush". Took forever until the fluid ran clear.
The rust comes right back.
I'm going to try the citric and maybe the evapo-rust. I've used that stuff before for other rust removal and it works pretty good.

 

[1969sag]

This was a few months after flushing and cleaning. I even took it to an oil change place for a "power flush". Took forever until the fluid ran clear.
The rust comes right back.
I'm going to try the citric and maybe the evapo-rust. I've used that stuff before for other rust removal and it works pretty good.

If that is after a flush.
I would make sure your engine ground is good. It is located at the back of the passenger side head and connects to the firewall. It needs to have good metal to metal contact. So you may need to remove a little bit of paint.
I use a little dielectric grease between the ground wire, head, and firewall, it seems to keep rust away. I also do not use the stock cable. I make a cable out of black battery cable.
JMO.

 

[stephanorf]

++ on the good block-to-firewall ground.

 

[1ofAMillion+]

Product? Lemon juice and/or Vinegar.
A citric flush will not remove all of the rust color, even after 4+ prolonged flushes for me. it does get better and better to a point.
I have read several good things about the evap-o-rust stuff removing all ugly colors. Dont forget to re-use that stuff.
One of the problems with worrying about the color of it is that there are many pockets where rust bits settle till its like beach sand. Water can't carry it away but I think it moves around enough to mix like a dye.
Also if its been sitting and rusty the freeze plugs are going to be weak and ready to blow with enough pressure, it is a good way to steam clean the engine though Behind each of the plugs are some pockets at the very bottom of the water passages where all the crap really settles, almost 1" worth that you can finger and get at but getting it all...??
I dont think flushing will ever get that stuff out without rotating the block so it can fall out.

 

[turbo2256b]

This was a few months after flushing and cleaning. I even took it to an oil change place for a "power flush". Took forever until the fluid ran clear.
The rust comes right back.
I'm going to try the citric and maybe the evapo-rust. I've used that stuff before for other rust removal and it works pretty good.

iTS NOT EASY STUFF TO REMOVE is sticky gummy almost hard over the years. Many passages have pockets and small passages in the heads, radiator and heater core. Best for radiator sometimes is best to have it rotted out. Passages in the heater core are even smaller and often requires replacement as rotting out dosent work.

Also its good to check voltage for in the the coolant with a multi meter
http://www.completeradiators.com/articles/34.htm

Could be oil getting into the coolant but it usally looks like grey puke and causes overheating
Dont ever use Dexcool in any car even the chevys it came in.

Mix coolant with distilled water only for best results.

Also you can look into Evens cooling http://www.evanscooling.com/
When I WORKED FOR fORD ENGINE DESIGN I was envolved wit ha meeting with Evans and had been using his set up on a 302 in my 84 mustang. Too pricy for ford to use think a gallon of coolant was around 30.00 at that time

 

[Fordguy65]

If that is after a flush.
I would make sure your engine ground is good. It is located at the back of the passenger side head and connects to the firewall. It needs to have good metal to metal contact. So you may need to remove a little bit of paint.
I use a little dielectric grease between the ground wire, head, and firewall, it seems to keep rust away. I also do not use the stock cable. I make a cable out of black battery cable.
JMO.

Anything magical about having the ground at the back of the head? I have a ground strap from the engine block to the frame at the front. Nothing really going from the head to the firewall.

 

[1969sag]

Anything magical about having the ground at the back of the head? I have a ground strap from the engine block to the frame at the front. Nothing really going from the head to the firewall.

That is where Ford thought it should be on almost every vehicle they made. The braided ground strap/wire they used usually rotted away though.

 

[RV6]

Anything magical about having the ground at the back of the head? I have a ground strap from the engine block to the frame at the front. Nothing really going from the head to the firewall.

A ground is a ground. Don't matter where it is. Ford chose the back of the head. The block to frame would work just as well.

 

[6sally6]

Using distilled water helps A LOT with the rust problem. Use a flush as listed above and then fill with distilled water and small amount of anti freeze for lube.
6sally6

 

[victor]

Get it as clean as you can and install 50/50 coolant and a Gano top hose filter. That should catch must gunk floating around and hopefully stopped your radiator from clogging. I have the same issue and the Gano catches everything. I change coolant when it discolors or every two years.

 

[Fordguy65]

Just an update. Did the citrus flush about a year ago. This pic is tells you how bad it was:

A year later and the fluid is relatively clear. I would definitely recommend doing this if you have the same rusty sludge.