RADIATOR FLUSH WITH VINEGAR

[charles walton]

I have a CAT D-6c and a 941b loader and I want to do a deep cleaning flush on the cooling system. Has anyone tried using vinegar and if so what ratio of water to vinegar and how long did you leave it in,did you run it long or just circulate it and then let it sit?

 

[Birken Vogt]

My personal opinion is, if it is rusty flush it with clear water until the junk is out. If it is contaminated with oil or something then it will need dishwasher soap and a good flush afterward. Not a fan of chemical cleaner because of the difficulty getting it all out. Plus one time I did that and the radiator sprang 12 leaks, the dirt was all that was holding it together.

 

[1693TA]

I use muriatic acid and water with thermostats removed. 2qts in a five gallon bucket is a good ratio. Learned that almost 50 years ago working in a radiator shop. If you have weak spots such as rusty core plugs or marginal radiator core, it could leak after this mixture is drained, rinsed with clean water, and then topped up with coolant of choice. I let the engine run an hour to come up to temp and stabilize, the allow to self cool to about 150 degrees, then drain, rinse, and refill.

 

[OzDozer]

You need to be real careful using Muriatic (Hydrochloric) acid in cooling systems. Muriatic acid attacks every metal, as well as the rust. About 3% solution is the maximum you want to go - and don't leave it to soak!

I don't believe Vinegar is strong enough to remove heavy corrosion in a cooling system.
I use Citric acid. About 5% to 10% solution, depending on the level of corrosion. It's safe (it's a food preservative, added to a vast number of foods, including bread), no need to worry about acid burns as with Muriatic acid, no need to worry about splashes etching everything the splashes land on, and no need to worry about kids finding it, and playing with it. And no chlorine fumes, as you get with Muriatic acid.
Citric acid can be left in the cooling system overnight, and even for a couple of days if necessary. It simply dissolves rust, and doesn't badly etch the base metal, as Muriatic does. It doesn't eat copper or aluminium and doesn't adversely affect hoses. It does help to pressure-wash the cooling system once you've emptied the Citric acid out.

For heavy black scale though, you would need a dose of Muriatic acid to clean that stuff out.
FWIW, Cat claimed many years ago that a 1/16" coating of scale on a liner or block will prevent 40% of the engine heat from escaping. Scale is the best insulation material since Asbestos!

 

[1693TA]

I've been working on an old air compressor that was used in a rental fleet for a lot of years. The cooling system is a mess with a lot of rust and sludge contained. I pulled the radiator, and sent it in having the bottom tank removed and the core "rodded" clean as it was partially plugged, and then pressure tested to 50psi. All was found to be good after this service. I've now added the muratic solution in the aforementioned ratio through the cooling system four times and this is the drain water just yesterday afternoon:



That sample was pulled as the muratic solution was draining. A final rinse was ran through the engine allowing to warm, then drained also. I'm going to do the same once again later today until the water is much clearer and then will add a 50/50 mix of coolant.

The operating temperature of the engine has dropped at least 15 degrees from prior.

 

[1693TA]

And if another Muratic acid treatment doesn't work, I'm going to mix up a solution of caustic soda, (sodium hydroxide) and run it for a short bit. I still use caustic in my aqueous parts washer cabinet for ferrous iron and steel parts. I pump this clear when washing anything non ferrous however as the caustic solution is not the most friendly to aluminum parts and I have other cleaner for that duty.

 

[Birken Vogt]

The problem with muratic acid is that it is hydrogen chloride. The chloride ion is what corrodes the metals over time. Same process as salt (sodium chloride) on metals. In my view, it's better not to introduce it in the first place. Vinegar and citric acid have only hydrogen, oxygen, and carbon, so no chloride in the first place.

For final rinse, I like to run a hose in the engine with clear water somewhere, usually the radiator fill, and let it pump the water out as fast as it can, such as removing a heater hose, until it runs clear. Finding the balance point of water in = water out. It's a pain but worth it.

All this can be avoided by just draining and refilling with fresh coolant every 5 years or so.

 

[1693TA]

You're right but some tasks require extreme measures to correct.

Here is the same water drain water this morning:



This is the ground around the compressor and again this is after the fourth flush and the first with the compressor sitting where it is:



Not to dispute but I'm going to keep on the same track with Muratic acid as I know it works. I dump this mixture in, start the engine warming to 180 degrees or stabilization temperature, allow the engine to run and dwell for 30 minutes, then drain and refill with fresh water. I then run the engine again for another 1/2 hour before draining yet again. Once the drain water runs clear (and hasn't yet) I'll refill with a 50/50 mix of ethylene glycol and distilled water. I have a drain port and ball valve on the block but so far each time I remove the pipe plug in the bottom of the lower radiator tank, the discharge is "chunky", so keep draining there. The first three drains were into buckets and you see the fourth in the photo.

I too would like to be as gentle as possible but sometimes extreme measures are called for. I'd rather a piece of equipment fail in my driveway rather than a jobsite so even if the engine were leak being corroded through, I'd install another engine before it goes back out. Regardless, I cannot have it overheating on a jobsite when it's depended upon which is what started this dilemma on a 96 degree day with pretty close to matching humidity, (92%) doing this:

 

[1693TA]

Drain water after 5th cycle of Muratic acid wash:



After the water was poured off, this is the "gunk" in the bottom of the cup and what I called "chunky" in a previous post. This is obviously corrosion of the engine metals so the engine cooling system has been neglected a long time.




After this I mixed up a five gallon bucket of caustic soda, (sodium hydroxide) to a value of 13 on the litmus strips, added this to the cooling system and blocked off the radiator cooling air flow with cardboard. I let this run slowly allowing more air across the radiator core modulating the engine temperature between 180, and 190 degrees the best I could over an hour engine run time. I had left my phone on the charger at home so no photos, but the draining of this batch was absolutely black in color. A fresh water rinse and drain was also very dark. Another rinse was perfectly clear. Another run for five minutes with clear water and it drains almost 100% clear.

I did notice a core plug, (freeze plug, frost plug) etc. leaking just above, and to the front of the starter. There are three in that area and all are easy to replace so that will be tomorrow or the next day if I can get them locally.

This is a photo of the control panel for the engine and you can see the engine temperature is at about 150 degrees. It is currently 83 degrees outside so a considerable difference in operating temperature from where I started.



Since Detroit two stokers have gotten so much quieter during operation in my old age, I'm looking to replace this B427 Continental gasoline engine as just too hard to get parts for on short order. The 4-53 Detroit was the diesel option for this series of compressor.

 

[chidog]

I've seen some comments on youtube videos about using muriatic to clean rust. Some say it goes into the cast iron pores and stays.
My opinion is no, since I thought it was used in the steel / iron industry for cleaning the metal. 1693TA, so what is a good ratio to use to clean individual parts, not a cooling system?

 

[1466IH]

I use a 1/3 muratic acid 2/3 water solution to clean fuel and hydraulic tanks a lot. Let sit overnight then drain and flush with water. Use a solvent sprayer to fog the inside of tank to disperse water and keep from rusting until tank gets filled again.

 

[1693TA]

Muratic acid readily breaks down and washes away. Stuck in pores; I've never heard of that but have always double rinsed to ensure it's neutralized. It's used regularly to balance the ph level in swimming pools for instance. I really don't use it hardly at all except for the occasional cooling system cleanse, and etching concrete just before painting to ensure adhesion. Back in the 70's we used to dump it into a spray gun and spray a paint stripped car down till it was running to dissolve any "flash" rusting, wipe dry and blow out the seams well. Then off to whatever process was next.

I still like and use caustic soda for iron, or ferrous parts, and a high alkaline cleaner for non ferrous or plastic parts. Both are effective on grease with caustic being very aggressive on rust removal. When the washing temperature is elevated, both work very well in their respective tasks. However to degrease parts I still have an old agitated "Graymills" solvent based parts washer which I keep mineral spirits in. 50 gallon of it and it lasts a good long while. This saves on the heated parts washer solvent costs by removing the grease. Large parts get the steam cleaner treatment.

 

[chidog]

Where to get the soda ? 1455IH the ratio? The muratic is usually not a very high concentration as sold. I forget what the label says for %. So are you using that % in your calculation?

 

[1693TA]

Muratic acid sold over the counter is just over 30% concentration and it's all I use. Just purchased two gallons yesterday for this task.

 

[Old Doug]

My pickup rad had alot of calcium build up. I capped off the rad and used alot of muradaic acid in it then flushed it good. I was afraid to run it through the system but the rad is very clean.

 

[1466IH]

Where to get the soda ? 1455IH the ratio? The muratic is usually not a very high concentration as sold. I forget what the label says for %. So are you using that % in your calculation?

For small tanks I just go to the local hardware store and buy the over the counter gallon jugs. For a big tank I usually get a larger container from NuWay. Never really paid much attention to the dilution but I am guessing it's all the 30%

 

[chidog]

Where to get the caustc soda?

 

[1693TA]

Caustic soda by it's more consumer mainstream name is "Lye" and available at most any home center or industrial supplier. It can be purchased online easy enough by the 50# sacks, or 1# packages. Ebay has vendors also. The key is to purchase "Litmus" strips to dip in your mixture to keep tabs on concentration, or effectiveness. Hardness, or softness of water has great bearing upon the needed concentration of chemical so the "Litmus Test" is the best way to know what is correct.

Don't run caustic soda through a cooling system with aluminum parts meaning anything aluminum at all. The caustic is very detrimental to them and especially thin walled items such as a heater, or radiator core. Muratic acid, (in my experience) does not bother these items in the amounts I have used.

I popped a compromised core plug from my engine this morning and it is very corroded. This allowed me to measure the hole and order replacements. I installed a rubber expanding stopper, (plumbing item) filled the cooling system with water, and pressurized the cooling system to 20psi with no further leaks noted. I'm excited to have this one seemingly wrapped as the engine was consistently running right at 190 degrees with the compressor section declutched from the engine. When clutched in, about 35 minutes and she was shutting down from overtemp of about 215 degrees, (indicated). I've not had the compressor section engaged during the cleaning process but I've not been able to get the engine over 155 degrees where it was a consistent 190+ prior so indications look good so far.

 

[1693TA]

Replacement core plugs arrived today but I didn't install them; yet. That may be tomorrow, or Friday s I've other things to do. A friend has the proper driver set I'll borrow to install with. However the cooling system of the engine has much less buildup in it. Still very bad in comparison to new, but hopefully will be functional and not overheat till I find a diesel replacement engine.

 

[1693TA]

Installed new frost plugs and flushed cooling system with clear water once again. Drained and installed 50/50 mix of ethylene glycol and distilled water, started engine and allowed to run up to operating temperature. Then shut engine off, allowed to cool and topped up the expansion tank.

Later yesterday afternoon I ran over and blasted a KW frame clean over the course of 4.5 hours and engine temp never elevated above 190 degrees. Outside temp was 89 degrees and 87% relative humidity so I am quite pleased with the outcome.