Massive amounts of rust in radiator

[jdwk]

So my stock radiator developed a leak a very long time ago.
But it was a slow leak, I knew where it was coming from and so I just filled it up with a quart of distilled every month or so.

Eventually I ponied up and bought an all aluminum radiator from Ron Davis.

When I emptied the old radiator, the amount of rust in there was alarming. Then with both ends of the engine open and the thermostat removed, I ran my (softened water) hose through the engine, and it took about 10 gallons before it was really clear with no rust.

I went half and half on the Prestone and distilled when I filled her back up, thinking the Prestone would help with the rust. (We don't really need anti-freeze in Phoenix)

Now, it's been a few months with the new coolant and it has piles of rust in the radiator. It's even clumped around the radiator cap. Dark red iron rust.

What could be causing my engine block to be oxidizing so quickly?

If my water pump isn't fouled up beforehand, it's going to eat away a jacket wall, and I'll be seeing white smoke before too long.

I know electrolysis can contribute if you aren't properly grounded, but I've gone through voltage test and while I do see a very small voltage .15V, it doesn't change when the car is on, running, or using accessories.

One thing I have noticed with this car. Is that during the winter months, it produces a very large amount of static electricity, zapping the crap out of me every time I get out of the car, even after very short distances. Whether this is contributing to the rust I have no idea. But other than dragging a grounding strap below the car, I don't have a solution for that either.

 

[BOOSTR]

That crap is in your block also, which is why it came back. Looks like the product of mixing dex cool with regular anti-freeze or serious neglect on changing the coolant as needed prior to developing issues. Get rid of your home brew and put some 50/50 ready mix in there after having it flushed professionally would be my suggestion.

 

[haveahotcarl]

The first problem that caused the initial rust you found is from using ONLY distilled water in your system. As warm as Phoenix may be, every car NEEDS some sort of antifreeze! The beauty of antifreeze is that it not only prevents freezing but, it also has rust inhibitors as a part of the formula. Albeit you may not need to go with a 50/50 or higher mix like I do in Wisconsin, you should at least do a 25% Coolant with 75% water mix. Not having the rust inhibitors, or slowly diluting them over time by adding only water, caused the cast iron block to rust.

Flushing the system like you did is good and can work, but the problem is that rust is hard to remove and once it starts, it is hard to stop. Even adding coolant later won't stop the rust, it could slow the rusting however. I agree with BOOSTR, you probably didn't get the rust all out, but I don't think a professional would do too much better.

The reason why you are seeing so much corrosion in such a short time isn't quite as simple of an answer. You are right, electrolysis can speed up the iron oxidation reaction. The voltage you are getting is definitely enough to cause electrolysis and should be looked into. Using a 50/50 mix probably did help slow the oxidation, but the rusting that has already occurred likely killed all the anti-corrosive properties of the coolant rather quickly and put you back to square one. Galvanic corrosion, dissimilar metals in contact with the presence of an electrolyte (impure water), can cause breakdown of the metal components. The aluminum radiator would corrode before the iron block, so galvanic corrosion can be ruled out (at least for the iron oxide rust). I think the bigger player in the rusting game is residual rust deposits left in the system. Either they are causing more rust or your new radiator is better at trapping the particles as they enter. I am not familiar with all the crazy chemicals that are out there, but I would assume there must be some sort of rust "eliminator" for automotive cooling systems. Someone with more knowledge of cooling systems could better speak to that.

Lastly, as for your static shocks in the winter, completely normal and actually caused by your ass (literally). Static shocks are often in the range of 1,000 to 10,000 volts and will not contribute to electrolytic corrosion in the cooling system. The dry air allows electrons to build when you slide off the seat and then the shock results when you touch a 'source' with a lower potential (not at 10,000 volts). Easiest remedy, touch someone else before you touch metal, at least you will get some enjoyment out of shocking them.

 

[jdwk]

BOOSTR: Yeah I know it's coming from my block; it's the only iron I know of in the cooling system. Definitely some neglect on my part, since I was only filling the radiator back up with distilled when it was leaking, and didn't do a complete flush for over a year. But that certainly doesn't seem long enough to develop this much rust.

However, I flushed it about as good as I'd imagine any shop would. It's 50/50 Prestone and distilled water. How would pre-mixed coolant be any better?

haveahotcarl: That is one of the most informed and intelligent sounding replies I've ever received on this forum. Thanks.
You are probably right on rust still in the block. I used at least 10 gallons of water, but ran out of containers to hold all the rusty water. It was pretty clear by the end, but could have been clearer.
I really hope there is a product that eliminates rust. Wonder how bad some hydrochloric would mess things up?

 

[haveahotcarl]

How would pre-mixed coolant be any better?

No, it is only a convenience factor. Just use distilled water and be sure to use the right mixture.

Edit: I wouldn't use any HCl in the engine...could form hydrogen gas and other Fe + Cl compounds you probably don't want in your engine block clogging it up.

 

[BOOSTR]

By professional, I mean using a machine and the proper chemicals for your SEVERE issue. Its beyond DIY mode but your choice of course to do as you see fit.

"RADIATOR
The most common problems radiators fall prey to are clogging (both internal and external) and leaks. Dirt, bugs and debris can block airflow through the core and reduce the radiators ability to dissipate heat.
Internal corrosion and an accumulation of deposits can likewise inhibit coolant circulation and reduce cooling. Backflushing the radiator and cooling system when changing coolant is highly recommended to dislodge accumulated deposits and to flush the remaining coolant from the engine block. Backflushing is running water back through the radiator and engine in the opposite direction to which it normally flows. After the coolant has been drained from the radiator, a T-fitting is installed in the heater inlet hose. The fitting is then connected to a pressurized water hose or power flusher. The water is turned on and the system is reverse flushed. The flushing should be continued until only clean water emerges from the radiator. Cleaning chemicals may also be used to remove accumulated deposits from the system.
When the cooling system is refilled, use a 50/50 mixture of ethylene glycol antifreeze and water. This will give freezing protection down to -34 degrees Fahrenheit, and boiling protection to 265 degrees F. in a pressurized system with a 14-psi radiator cap. A 70/30 mixture will protect against freezing down to -84 degrees F. and boilover up to 276 degrees F. Do not use more than 70% antifreeze because antifreeze carries heat less efficiently than water. Straight water should never be used in the cooling system because it offers no boilover or freezing protection and no corrosion protection (which is extremely important in todays bimetal and aluminum engines)."

http://www.arrowheadradiator.com/preventing_cylinder_head_gasket_and_cooling_system_failures.htm

 

[jdwk]

If you got a shop that had the right tools and followed that procedure correctly, it would be better than I could do in my garage. But that is a big if.
I've yet to find a shop out here I can really trust (I don't think mazda has ever gotten any of my problems right the first time), and it's not so much the shop as the actual person working on your car. The turnover out here is so bad, you have no idea who is actually working on your car.

Even if you are standing right there, sometimes you can't stop them quick enough. I just got new tires put on my other car, and the wheels have chrome painted lug nut covers. He knocked the covers straight out to the ground onto their face, and then he put his pneumatic on the ground next to it, which promptly sprung back snagging the cover and scraping it along the ground for 15 feet.

I may screw stuff up, and I may let things get out of hand sometimes (case in point), but at least I know what I messed up and usually learn something in the process.

So Prestone makes a whole line of coolant flushes. One is even called Super Anti-Rust. Guess that's right up my alley. Now if I can just find it in a local store, otherwise it looks like I'll be ordering a case of it.

Thanks for your help guys, I'll post back the results in a couple days.

 

[andrei1989]

i had the same problem too and i also repaced the radiator. I did the same with removing the thermostat and just ran a garden hose and kept circulatiing water through it until it came out clear. THen i put the new radiator in and put some of that flush stuff in and drove like that for a while..and the coolant got a little brown so i flushed it again...and refilled it with 50/50 coolant and had no problms