Have you had a heater core fail, then replaced it only to discover it fail once more within a yr or much less? Or have you had a radiator fail in the inside out as a result of corrosion or pitting? These may be signs of cooling system electrolysis corrosion.

Electrolysis corrosion looks to be a frequent difficulty on numerous late model motor vehicles which have aluminum heater cores and radiators. Electrolysis is actually a chemical reaction that takes location concerning the coolant and metal surfaces. From the case of an automotive cooling system, by far the most vulnerable metal is aluminum, particularly if the engine has an iron block. Aluminum is softer than iron, and it is much more reactive to the two acids in the coolant and electric currents while in the coolant. Consequently, when the corrosion inhibitors within the coolant are worn out since the coolant has not been transformed in many years, or you’ll find stray electrical currents that are flowing throughout the coolant because of missing, loose or corroded engine ground straps, electrolysis can eat away with the heater core, radiator and any other aluminum parts within the system (including the water pump and passageways in aluminum intake manifolds and cylinder heads).

Symptoms of Cooling System Electrolysis Corrosion

* Coolant leaking in the heater core, plus the appearance of tiny black pinholes anywhere on the heater core. Coolant leaking from the heater core will ordinarily leave drips, wet spots or stains around the carpet around the passenger side from the automobile. Steam or maybe a greasy vapor may possibly also be seen coming in the A/C and heater vents within the dash once the heater or defroster is on. The gradual loss coolant will cause the coolant degree to grow to be low, plus the engine to sooner or later overheat.
heater core leaks brought on by cooling system electrolysis corrosion

* Coolant leaking from the radiator, with all the appearance of smaller black pinholes on the metal parts of your radiator. Just like the heater core, electrolysis corrosion has eaten through the metal from the inside out.

* Coolant leaks at intake manifold gasket connections. This type of leak is ofen resulting from a softening from the plastic carrier and seals on particular intake manifold gaskets that occurs with time, however it may perhaps also be caused by corrosion eating away at the coolant ports while in the cylinder heads and consumption manifold. If ample metal erodes away, the consumption manifold gasket may no longer be adequately supported and allow coolant to seep previous the seal. Replacing the intake manifold gasket will not always repair the leak unless of course the replacement gasket includes a wider sealing location with numerous sealing beads (which some aftermarket gaskets do). The eroded locations throughout the ports could have to be repaired by using a higher temperature metal-filled epoxy, then sanded flat and smooth before the gasket will seal appropriately.

In some instances, a heater core will fail from your inside out because of erosion as opposed to electrolysis. Erosion can be a physical sporting away of the metal brought on by dirt, grit and sediment circulating inside the coolant. The heater core is most vulnerable to dirty coolant as the tubes in the core have sharp bends. Because the contaminants circulate together with the coolant, they put on away with the inner surface in the tubes until eventually sooner or later the metal perforates and springs a leak. The same factor can come about on the plastic finish tanks on an aluminum/plastic radiator, or the plastic impeller within some water pumps. Any junk during the coolant may have an abrasive impact and wear away the softest material it comes into make contact with with, be it plastic or aluminum.

Radiator and heater hoses may also fail from the inside out resulting from electrolysis corrosion. Rubber is ordinarily non-conductive so you would imagine this can be unattainable. However the coolant can react electrochemically with the synthetic rubber, resulting in it to degenerate, pit, crack and at some point fail. For those who reduce open a hose that has failed because of electrolysis, the inside will generally have fissures, cracks and pits developed through the electrochemical attack.

Leads to of Cooling System Electrolysis Corrosion

Cooling system electrolysis corrosion can be attributable to two points:

Worn out coolant. This is normally the end result of not transforming your coolant typically ample. As time passes, the corrosion inhibitors in each and every type of coolant put on out. For standard green formula coolants, this will happen after two or three years or 30,000 to 50,000 miles. With “long life” OAT and HOAT formula coolants, the corrosion inhibitors may well no longer have the ability to guard your cooling system soon after five years or 100,000 miles, which ever comes very first (not final!). As soon as your coolant turns from alkaline to acidic, electrolysis starts to eat away with the metal surfaces within your cooling system. Sooner or later on your cooling system will start to leak.

Stray electrical currents while in the coolant. Worn out coolant is more electrically conductive than great coolant. Also, the coolant can serve as an alternate path to ground for your vehicle’s charging system and electrical system if there’s not a great ground connection concerning the engine, charging system and body (chassis). Loose, corroded, broken or missing ground straps concerning the engine and chassis are a common lead to of this sort of electrolysis corrosion.

Ways to Examine for Electrolysis Corrosion

Together with the engine running and at ordinary operating temperature, use a digital voltmeter to check for voltage among the coolant as well as battery unfavorable (-) cable. Properly remove the radiator cap or coolant reservoir cap (use a rag and open gradually as being the system is going to be beneath pressure and hot steam could blow out of the opening). Insert the positive (+) voltmeter lead during the coolant, and touch the adverse (-) voltmeter bring about the battery unfavorable publish. Should you see a zero reading through, that’s superior as it suggests there’s no stray electrical recent flowing from the coolant. But if you see a reading of 0.300 volts (300 millivolts) or larger, you’ve got electrolysis and likely trouble.
measuring coolant voltage
The voltage studying for the coolant among the coolant reservoir and battery negative terminal with all the engine idling is significantly less than 300 millivolts, which means the coolant is great and there is certainly no electrolysis taking place within the cooling system.

You’ll be able to examine the affliction (reserve alkalinity) from the antifreeze in the cooling system with chemical test strips that adjust color when dipped inside the coolant. These test strips can be found at most auto parts shops. Should the test strip demonstrates the coolant is acidic (poor), or is borderline, you need to alter your coolant now!
coolant test strips
The test strip demonstrates the coolant remains to be excellent.

Getting rid of Cooling System Electrolysis Corrosion

If it’s been over five many years due to the fact you have modified your coolant, drain and flush your cooling system, then refill it using a 50/50 combination of fresh lengthy lifestyle coolant and distilled water. Will not use ordinary tap water or softened water mainly because tap water can include dissolved minerals and soften water consists of salts which have been corrosive and can shorten the life of the corrosion inhibitors while in the coolant. Greater nevertheless, refill the system with pre-mixed antifreeze that previously contains distilled water and it is mixed inside the appropriate proportions.

If your old coolant displays signs of neglect (sediment, scum or extreme discoloration), flush your cooling system with a chemical cleaner item. Normally, you add the merchandise to your radiator or coolant reservoir, run the engine until eventually it really is warm (so the thermostat is open along with the coolant is circulating in the system), turn around the heater (so the cleaner will circulate from the heater core, too), then drive your motor vehicle for about 10 minutes or so to loosen all of the crud and sediment within the system. Then you certainly shut off the engine, allow anything awesome, and drain the radiator.

Stick to the directions to the merchandise to your letter and make sure you completely flush the system afterward with numerous gallons of clean, distilled water. This is necessary to remove all traces with the chemical and sediment from your system. Carry on flushing till you see nothing but clean water coming from the radiator drain valve.

Check out the engine ground straps and ensure they can be tight and in very good condition. If in doubt, remove and clean the ground strap connections, then reinstall and tighten for making positive there is certainly very good electrical make contact with. Also verify any ground straps about the alternator, and also the battery cables (each ends).

In some instances, stray electrical currents can uncover their way to the cooling system if aftermarket electrical accessories such like a stereo, Cd player, lighting, and so on. usually are not correctly grounded to the chassis.