can someone explain electrolosis in a radiator

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or any google ;)

Me thinks you got reamed...

It is quite probable, certainly if you have 2 dissimilar metals, water & a bit of stray electrical current. (Or even the incorrect coolant)
That is exactly the reason why moored boats & outboard motors have sacrificial anodes.

So, you may not have been "reamed".

There is a Potential electrical difference between you radiator and the rest of your car/ engine (dissimilar metals) and a current is flowing and the Radiator being the “Anode” in this case is being disintegrated in front of you eyes.

Another example of this> 302 Windsor, due to poor eathing It caused a hole to be eaten in the timing cover made of Aluminium block cast iron and allowed coolant to mix with oil and create this sprog LOL

Electrolysis is the production of crystalline or other deposits due to stray electrical currents. If you have an earth taken for say a second battery from a radiator mount or even mineral rich water or dirty water in a radiator it will carry electrical current and commence the process of electrolysis.

In some cases electrolysis causes rust and deterioration of metal, such that in high pressure gas mains, they have electrolytic protection and they use what they call a sacrificial anode.

If it were me I would check all mounts and maybe run an earth wire to the radiator mount.

Electrolysis is nothing like being reamed

Tone, these two links are interesting.
Stray current article
Aluminium radiators

Cheers
phil

If your prado has an electric fan on the radiator, check its earth wire too....possible it has a bad earth and is using the rad body to get a better one...best idea is to run an earth wire from the electrical equipment hanging off the rad to the battery.
On another note...
I dont know how true this is...but it sounded like it had enough merit for me to put out amoungst you....so i would appreciate any feedback....
Alloy headed motors.... by means of wear and tear, bits of alloy cast like sand particles break away inside the head and start circulating through the cooling system. Electrolisis or magnetism or whatever it is makes these pieces of alloy sand congregate in the middle of the radiator, furtherst point from earth.....when enough clog the centre of rad....thermo fan hub doesnt pick up heat from passing coolant, so does not engage properly....resulting in blown head gaskets....
TRUE or FALSE???????????

Any two dissimilar metals and an electrolyte can provide electrolisis. Corrosion (rust) is a form of electrolisis. It just depends, to a large degree, on the atomic weight of the metals... Ie copper & zinc with a little water (not distilled) in a non conducting container will react enthusiastically and the zinc will dissolve....From what I know the coolant has to be the one specified for the engine, read the containers and make certain that the one you intend to use is suited to the engine. If you have an alloy head and a copper/brass radiator the correct coolant is essential.

2 years and it was serviced by an authorized Toyota dealer.....

Has everyone missed the point!! 2 years!! Properly serviced and maintained by Toyota. Imagine what all radiators would be like when we abuse them. They most likely would last only one year at that rate.

I think you have been conned and they have just offered that up for an excuse. I cannot believe a Toyota radiator would last only 2 years. It should be at least 10 years before you start thinking about clean outs and leaks.

If this was the standard lifetime of a Toyota radiator, I wouldn't be buying Toyota.

Cheers.

Was the radiator leaking or were you having overheating issues? If not I'd say you've been 'reamed'.

I've got some interesting information from Denso (one the world's largest OEM radiator manufacturers) regarding aluminium radiators, flushing techniques and testing for stray current. I'll post them below, the 1st one is about radiator failures.
They are bit long but they have all the info you'll ever need.
Regards Andrew.

Radiator failure information from Denso & NRMA.

Premature radiator failure-/causes.
Corrosion ¬- Internal and External.
Erosion - Internal and External.
Stray Current - Electrolysis Internal- External.
Mechanical Damage - External.

Stray currents cause premature corrosion failures in radiators, water pumps and thermostat housings as well as premature ageing in coolant hoses. When we say premature, we mean in as little as three months.
NRMA Insurance did a front end repair on a VW Golf in which the radiator was replaced, three months after the owner took delivery it was found that the new radiator was so badly corroded it was irrepairable. The radiator core was dismantled and showed evidence of extensive electrolysis and mixed coolants.
Do’s and Don’ts:
# Never mix different brands of coolants or inhibitors. Mixture of incompatible coolants can induce radiator fouling and can reduce the corrosion protection of the coolant. Always flush out the cold coolant.
# Never use coolants that foam as this will lead to increased cavitation erosion of the water pump. Shake the bottle of coolant then let it stand for 5 seconds, if the foam has broken and the fluid has returned to normal then it probably won’t foam in the cooling system. If the foam has not broken after 5 seconds then it might pay to find another product.
#Never undertreat a cooling system as the incorrect ratio of coolant can actually increase the corrosion rate to above that of plain water.
#Only use the best quality water. De-mineralised is the best, never use bore or spring water.
#Always check for stray electrical current in the cooling system.
# If the vehicle is within the new vehicle warranty period, always use the manufacturer’s recommended coolant as to do otherwise could void the warranty should the cooling system fail.
# Always use the service stickers supplied by the coolant manufacturer to avoid any confusion as to which type of coolant is in the system when a top up is required.
#Always dispose of used coolants correctly. All used coolants will contain heavy metals irrespective of their claims of being environmentally friendly.

“Whilst not wanting to pick on any one area of the automotive industry, our own experience tells us that many vehicles we have examined for electrolysis and chemical corrosion damage are those that have had recent paint and panel repairs. If you suspect that a radiator has failed from electrolysis and you can’t find any apparent reason for it, look for signs of recent repairs (keep in mind that the problems can exist right from the time the vehicle was manufactured)
If you spot repairs, be wary of earth wires that:
1: Are not connected.
2: Are loose, corroded or insecure.
3: Earth wire mounting points have recently been painted, thus paint may be down the threaded holes causing poor earth contact.
4: Whist you are monitoring the presence of stray voltage in the cooling system, have a fellow worker operate the brake lights, parking, head and high beam lights and check for any increase in voltage readings in your multimeter
5: Also, turn on as many accessories as you can to load the vehicle’s electrical system whilst monitoring stray current.
6: Check battery cables and mid cable securing points for corrosion and tightness.
Testing for Stray Current.
Using your multimeter, connect one lead to negative side of battery and then with a test probe immersed in the coolant, make sure it doesn’t touch the core and for a proper reading the probe must stay in the same place in the neck at all times. If a current measuring above 50mv is present you then have to start looking for the source.
At this point, we have to say that if you have found a problem relative to the stray current, CHANGE THE COOLANT. Unfortunately we have found with some brands of coolant that their chemical composition does not allow them to dissipate the charged oxygen hat has resulted from stray current, so if you are unaware of the coolant in the system, flush it and replace it.
Common Sources of Stray Current.
1: Ford Laser: Multi earth plugs located at the front of both chassis rails, Check the thermo fan earth circuit.
2: Ford Falcon: Main battery earth cable fitting at the engine block. Wiring harness fitting at the right front inner guard.
3: Holden Commodore: Main battery earth cable fitting at the engine block. Rear stop light wiring harness earths. Earthing point located behind right front headlight.
4: Nissan Pulsar: Brown coloured earth cables attached to right side rear cylinder head bolt. ECU earth. Earth circuit for thermo fan.
5: Early Hydundais: Multi earth wire point located at left front inner guard, cut this off and replace with eyelet connectors.
6: Sigma/Magna: Main battery earth cable (both ends)
7: Nissan Skyline/Pintara: Air conditioning fan earth circuit, change from condensor mounting to adjoining radiator support panel threaded hole.

Unfortunately, in recent times we are coming across more and more cooling systems and engine failures associated with chemical corrosion. It is a problem common with poor quality inhibitors, low dosages of inhibitor, but we see many where different brands of inhibitors have been mixed and the results are catastrophic.

The mixing of different brands can degenerate into the formation of a chemical cocktail, which can strip metal away with amazing speed.
The internals will show a dark Grey or black discolouration. You can also try removing the radiator cap and feeling the top of the core tubes, they will feel flexible, even soft to touch.
Where this indication is present you may also find items such as thermostat housings and water pumps showing signs of cavitation.

Where chemical corrosion has occurred, quite often the cooling systems components such as the thermostat housing, water pump, heater and coolant pipes will be badly discoloured.
Chemical corrosion can also lead to the formation of small hard deposits of metals and rust within the radiator or engine block causing hard to find overheating problems. These deposits can be very hard to shift if they have been building up over a period of time and as such, become firmly lodged in coolant tubes and within water passages, etc. Keep in mind that 1.6mm of corrosion build up on aluminium causes as much heat retardation as 10.4mm of cast iron.

Mixing of coolants and even poor quality coolants can cause foaming and it’s the introduction of oxygen that leads to the formation of air bubbles that create their own version of cavitation erosion.
The bubbles or vapours, which result from the chemical activity, continually explode against the engine’s hot spots and if not caught early can completely destroy an engine. The exploding bubbles of air cause a hammering effect on the metal gradually eroding away that area and eventually forming a small pin hole. Often a large piece of metal will simply disappear from within the engine. Cavitation can be particularly harsh on cylinder liners and their seals and at different points of the cylinder head and gasket.

Stop Press
Don’t assume that fitting an earth wire directly to the radiator core is a fix all, We did a test on an aluminium core and the wire actually increased the current.

The 2nd one is an explanation of stray current and the testing procedure required.
Regards Andrew.

Stray Current explanation & testing procedure.

In simple terms stray current is a chemical/electrical process which causes an electrical current to pass through a vehicles cooling system fluid. It can cause rapid damage to radiators and will indirectly cause problems with other engine components such as water pumps, thermostat housings, etc.
This is brought about when one or more items such as a cooling fan or headlamp develops a problem in its electrical circuitry. This causes an electrical current to seek out an earth path via the radiator core through the engine coolant.

1:Remove the radiator cap and run the engine to operating temperature. Do not rev the engine as this may cause the coolant to aerate. Note: Removing the cap will reduce the boiling point of the coolant. This may result in electric cooling fans not operating on some vehicles,
2. Switch ON all electrical items including Items such as a mobile phone, rear demister, driving lights, etc.
3. Switch an analogue multi-meter to a scale of 5 volts DC or less. Ideally the meter should be capable of reading millivolts. Do not use a digital multi-meter, as its internal operating characteristics are not suitable for this test.
4. Place the negative lead of the multi-meter on the battery negative post.
5. Dip the positive lead into the coolant without touching the filler neck or the core of the radiator
6.A reading of more than .05 volts indicates the presence of a potentially damaging stray current passing through the coolant. Ideally the voltage should be 0 volts, however it is highly possible that some voltage level will be detected
7. If no voltage or a very low voltage is detected, carry out the same test as in point 4, but with the ignition OFF.
8. If voltage is detected, isolate the circuit by turning all electrical items OFF and switching each circuit ON individually.

Caution:
Refilling a cooling system with coolant will itself generate a current that lasts approximately twelve hours.
This can be avoided by refilling a repaired vehicle, for example, with clean water and then proceeding to test for stray current.

The last one is the radiator flushing procedure.
Regards Andrew.

Cooling System Flushing Procedure.

Because coolant/inhibitors from different manufactures have different chemical compounds, which may adversely react if mixed, it is important that you DO NOT create a chemical cocktail within your cooling system by mixing different brands of coolant/inhibitor. Even though the coolant has been drained from the system, the inhibitors remain affixed to the cooling system components and must be chemically removed, using a quality alkaline flush.

Procedure:
1: Ensure the cooling system is sound and free from leaks and check all components for wear and condition. If need, replace worn components.
2: Choose a quality alkaline cooling system flush (500mL. Per 12 Litres). Observe the instructions on the container.
3: Replace the radiator cap and run the engine at operating temperature for 15 minutes in 4 cylinder vehicles and 30 minutes in 6 or 8 cylinder vehicles. (Ensure the vehicle heater is turned on).
4: Drain and rinse the cooling system including the overflow bottle and heater core. At this point a power flushing machine may be used if this equipment is available.

And/or:
4a). Rinse the system with clean water until you are convinced that the only fluid remaining in the system is clean water- RINSE- RINSE- RINSE (this may need to be refilled and drained a number of times).
5: Refill the cooling system using clean water (demineralised or distilled water), to perform a stray current check.
6: Do not add coolant at this time until a complete stray current check has been performed (refer to stray current procedure). The presence of stray current will deteriorate the cooling fluid quality immediately.
Always ensure you select a coolant/inhibitor that meets the vehicle manufacturers recommendation or one that meets AS 2108-97 Type A or Type B whichever is recommended as being in support of the vehicles manufacturers recommended coolant performance standard.
7: Ensure the correct rates of coolant/inhibitor is used, as overdosing or underdosing will have a direct affect on the performance of the cooling system and the life of the components including the radiator.
8: Only after the vehicle has been cleared of the possibility of stray current (electrolysis). Rebuild the cooling fluids by first adding the selected product then topping up with clean water (demineralised or distilled water). NOTE: NEVER MIX TWO BRANDS OF COOLANT!
9: Mix a portion of the coolant for the owner to use for topping up coolant level.

Dispose of Waste Fluid Correctly.

NOTE !
Radiator manufacturers warranty does not cover internal or external corrosion.

thanks to all - v.good info for me. I don't understand electrolosis any better, but can appreciate that it is BAD and looks like I have a earthing problem somewhere!

Had the same problem with a Ford Econovan work vehicle.Had a front end collision which stuffed the radiator.6 months after front rebuild I was travelling on highway at 110km/h and was engulfed by steam INSIDE the cabin.Couldn't see a thing....very scary. Found that it was the heater core.So now I check the WHOLE cooling/heating system occasionally to look for signs. The heater core when we removed it was white and very fragile.Have two good friends who are electronic engineers and they sussed the whole system for stray current and fixed whatever they fixed.But I still check occasionally!