Topic: Coolant Rust Flush

[66RagTop]

Any suggestions on the best process to flush rust out of an engine cooling system?

[cobrajetchris]

I have personally never tried it on a coolant system but I bet if you put a gallon of Evaporust in the system and let it run for awhile and sit in the radiator for a few days and flush it out it would work very well. I have used the product for removing rust on many parts with success and no damage. Just make sure you flush the system thoroughly with Water after draining the system and then replace with coolant. 

[Smokey 15]

 I have used some of the off the shelf radiator flush products. (I do remove the thermostat and replace it with a restricter so the water always flows. You can make one by cutting the center from an old thermostat) They seem to loosen some scale and rust in the system. Once done, I flush it completely out of the system 'til the water runs clear. I then run straight water for a few miles (or a 1/2 hour if you don't drive it) then flush again. I repeat the process 'til I get nothing clear water from the system. Then replace the thermostat and add water coolant/water mix you normally use.

[markb0729]

The Mercedes Benz citric acid flush runs circles around the typical off the shelf flushes.

A cheap alternative would be to drain the coolant, refill with water and add a couple of tablespoons of powdered Orange Tang.  Run at 30 minutes operating temp.  Drain and refill with water.  Run at operating temp another 10 minutes, drain and refill with coolant.  Tang cleans the hard water stains out of my dish washer like magic.    It creates a mild citric acid solution.  If you don't know what Tang is then google it.

[tomtri66]

I have personally never tried it on a coolant system but I bet if you put a gallon of Evaporust in the system and let it run for awhile and sit in the radiator for a few days and flush it out it would work very well. I have used the product for removing rust on many parts with success and no damage. Just make sure you flush the system thoroughly with Water after draining the system and then replace with coolant.

This is an interesting idea.  has anyone ever tried it?

[sgl66]

This is an interesting idea.  has anyone ever tried it?

Evaporust sells a product called Thermocure intended to dump in a cooling system. I tried it last year out of curiosity and didn't see any measurable difference but I started with a relatively clean system anyway. Your results may vary.

[CharlesTurner]

Consider going to a waterless coolant like the Evans product.

[67gtasanjose]

Here is your basic problem. Rusty cooling systems are basically a real bee-atch to get fully clean using a simple "mechanic-in-a-can" approach.

Sediment sitting in pockets of the block, heater core, radiator & such prevent a simple "solution" type 100% cure or removal of the rust. If you have ever been to a radiator shop and see what comes out after an initial "cold" flushing of a rusty water radiator, you get only a clue of what is trapped inside the engine block and elsewhere.

Sure, the solutions will help break down a good majority of the fluent rusty-colored water (coolant), but that sediment is still stuck in pockets (mostly in the block, have you ever knocked out a freeze plug and found nothing but orange mud ) and will likely continue to break loose, little by little, recontaminating the coolant again.

POWER FLUSHING is the best way to get +90% of the sludge out. I'd suggest having it done professionally. Environmental issues of just dumping old coolant & residue down such places like storm drains and sewage systems so be careful where you get rid of your sludge too if you end up doing it yourself anyways.

[67gtasanjose]

Don't underestimate the time it takes to get done right. The worst 289 as far as rusty coolant I worked with in a running Mustang took a couple days of flushing with straight water to get running clear, then the Mercedes flush was used on it. Worked great!

Problem with taking it to a "professional" shop is they don't have the kind of time you do over a weekend to run the car up to operating temperature, let it cool down (so you don't crack the block), then drain, and repeat over and over and over and over and over again.

I am a professional who does this, so I know they are out there. TRUE, I wouldn't take my car just anywhere either. Ask friends & family for a trustworthy shop in your area and ask that shop how they would go about it on a Classic car vs a daily driver Honda (or the likes).

Personally, I'd rather know this muck isn't flowing out into our rivers & streams. NO, I am NOT a "tree hugger" but I have seen my fair share of hazardous messes in peoples side yards while their drinking water well is within a few feet of, say just one example, where somebody was steam cleaning engines!

[KevinK]

I have heard of good results using the Ford Diesel  Engine flush.