Cooling System Electrolysis

[bmwdirtracer]

Is your coolant eating your engine alive? Did you know that improperly wired aftermarket electronics, or even a poor ground wire, can literally corrode your engine, from the inside out?

An electrical charge in your coolant as low as .15 volts destroys aluminum very quickly, and I've seen many cars with twice, even three times, that voltage in their cooling systems.

There are two ways this charge can occur: (1) a poor ground or improperly wired accessory can cause the coolant to become a ground path for battery voltage (or even static electricity), or (2) old coolant which has lost its protective elements can start to swap ions with the aluminum and other metal components, causing the coolant to become an electrolyte, much like a battery, producing its own electrical charge as it eats the aluminum.

For those of you with a multimeter, here's a quick test:

Set your multimeter to voltage, with a range of 0.000 volts.

Attach the negative probe to the best ground - ideally, the battery negative post, although the main ground post underhood will do, in a pinch. Ground the positive lead of the multimeter, momentarily, to zero the meter.

Then dip the positive probe of the multimeter into your coolant. If you see a voltage of 0.15 or above, it's time to change your coolant. To make sure the problem is old coolant, and not a bad ground or electrical issue, detach the negative cable from the battery, and use a ground point underhood. If the electrical charge is still present, your problem is in the coolant.

Coolant should be changed every two years, and you should use BMW blue coolant and distilled water.

[Yahweh]

Some good info in there. What I have noticed on newer cars is they dont get a coolant flush as Scheduled maintenance. But the failure of the components in the coolant system usually fail every couple of years where then the coolant is flushed or topped off....

I used to have some info about the new Blue bmw coolant vs older crap.

[bmwdirtracer]

It is worth noting that the vast majority of "coolant flushes" change less than half the coolant, because the block is left undrained.

[thejlevie]

Right!

The life of coolant is that of the corrosion protection package. That package is mostly a group of chemicals that scavenge oxygen from coolant. When the chemicals can no longer scavenge oxygen, corrosion begins. That means that for best life you mix anti-freeze with distilled water. Tap water contains oxygen and dissolved minerals, which cause an immediate depletion of the corrosion protection package. Distilled water contains neither.

[bmwdirtracer]

I'm bumping this, because I feel it's useful.

For a little added bonus: Sears sells their top-of-the-line Craftsman multimeter for about $100, when it's on sale. It has a point-and-shoot infrared temp sensor, built in - one of the best bargains of the tool world. When you have a cooling issue, it's really damned helpful to know the hose temps....

[GunnerNell]

I say again -- I learn something everytime I read one of your posts, Dirtracer. So again, thank you.

[bmwdirtracer]

Gunner, you're one of the truly great pleasures and gentlemen at this forum. If I've ever been of help to you, I'm very grateful for that opportunity.

Friends, it's been a BMW cooling system kind of week, in Hawaii, so check your systems carefully! Four down,, three more tomorrow; it's only Wednesday, and I had Monday off!

[bimmer_boyis]

Interesting. I've honestly never put much thought into the matter. Should be an excellent way to dispell BMW's "lifetime" coolant. Quick upsell tool if you have a writer that actually knows what they are talking about.

[bmwdirtracer]

I run the multimeter test on every BMW I see, damned near. (I don't get to work on many cars less than 4 or 5 years old). My race BMW gets a weak solution of fresh coolant mix every single year with water wetter. My street car, every year and a half, or so.

"Lifetime coolant", huh? I'll take that to mean that the coolant generally outlasts the first cooling system part that exploded, or the warranty, whichever comes first. Like "Lifetime ATF", I call that BS.

Everyone neglects their car; but it is my very firm opinion the there's not a fluid in the automotive world that doesn't need to be changed at regular intervals. Oil, brake fluid and coolant are my top 3.

[shadowpuck]

I say again -- I learn something everytime I read one of your posts, Dirtracer. So again, thank you.

same here......

thanks, as always, for posting up and sharing the knowledge.....

[dworthy]

Chris always has good tid bits of info. Don't forget about doing the same thing with the brake fluid too. I get quite a few cars in the shop that it looks like 30 weight, and people wonder why their brakes stick.

[Crescent]

For some reason all this lifetime crap started popping up out the left field when car companies decided to give away free maintenance as part of their supposed value. Yet I don't think they'll be coming up with a lifetime car anytime soon. Almost a century later some manufacturers still can't even get their spark plugs (Fords between spark plugs unable to be removed and ones that keep spitting them out ) right but they have engineered lifetime fluids for some harsh running conditions. Somebody should sue them for misleading the public if they didn't already buy that law out of the books.

[Schneldorff]

Fact= many coolants are formulated for many car manufacturers. Most all of them say to use their coolant. $

[bmwdirtracer]

Fact: I, and every BMW pro tech and racer that I know uses only BMW blue antifreeze. The formulations of various antifreezes are very different; after you've witnessed the coagulant effects of Volkswagen pink, or DexCool orange antifreeze, you'll likely stick with the blue stuff. I truly believe it to be the most anti-corrosive coolant, mixed with distilled water, of course. Sure, it'll cost you an extra eight bucks, once every two years.

[dworthy]

My wife always asks why I have to use the expensive stuff on the cars. I just reply with: How much does peace of mind cost? Do you not like to just jump in your car, turn the key and not worry about how far it will go before something breaks?

Sure you can skimp on some stuff, but I would rather perfer not to since I keep my cars till they are around 20 or so.

[IamHanSolo]

Ok, so I'll throw this out there because after this weekend, this is my number 1 priority. How do I get the crap green coolant completely out of my 92 E32? I just bought the car 10 days ago and it already has temp creep while stopped in traffic. On Sunday I wanted to check the coolant so I opened up the bleed screw and topped off the reservoir while the heater fan was on. Guess what came out? Green antifreeze... I know this is a bad situation from reading some of Shogun's posts about it, but I didn't get a clear picture of how to purge the system so I can put in the blue. Will I need to remove the plugs in the block?

[thejlevie]

Drain the radiator & block, refill with plain water, and bleed the system. The engine will be at normal temperature when the bleed is finished. Let it cool down and repeat. Then fill with BMW coolant mixed 50:50 with distilled water.

Just in case, I'd replace the thermostat while the system is dry and if it has 100k on it, the water pump, radiator, expansion tank, all hoses, and the fan clutch.

[IamHanSolo]

Awesome and thank you. Another question: should I run any kind of flush through the system? I have no idea what may be in there. The car has 260k on the clock, and I don't know when the system was last serviced, so everything will be replaced.

[thejlevie]

Using a commercial flush compound is good practice in my opinion. Do it after replacing the cooling system.

[IamHanSolo]

And the reason for using it after the parts swap is? My thought is that it might contaminate the new system.

[GasTurbine]

Interesting. I've honestly never put much thought into the matter.

Thats because in fact, its rather rare.

[dharmabmw]

Any thoughts on adding water pump lube to the coolant? I have used it and have saved my water pump bearing from premature failure.

[bmwdirtracer]

Thats because in fact, its rather rare.

There is NOTHING "RARE" about cooling system electrolysis. Have you ever measured the electricity in your coolant? I do it on almost every car I attend to - that would be hundreds of cars, every year --and pretty much every car with coolant over three years old has dangerous voltage in the coolant. Do your research - I have.

I wish I could show you the cylinder heads I've seen where the coolant actually corroded its way to the combustion chambers. At this very moment, I have a Mercedes head at the welder's shop, having metal added to replace the rotted aluminum.

[IamHanSolo]

Dirtracer, I think he was referring to the "thinking about it" part as opposed to the coolant electrolysis part. Just me 2 cents.

[bmwdirtracer]

Oops, that would make sense, huh? Must have been a rough day, sorry, Gasturbine, I forgot to engage my brain.