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Frango100 05-20-2012 09:50 AM

Grounding of radiator
 
I changed my radiator some time ago and just now was thinking that it is not grounded at all. It is mounted with the plastic side tanks, but the aluminum core has no ground strap. I think it was Ypahihi who changed his radiator twice within a short timeframe due to a pinhole leak probably caused by currents flowing through the coolant, eventhough i don´t know where that current should go to. Measured the voltage difference between the coolant and the negative battery pole, which started at 40 mV, but then lateron dropped to around 15 mV. But i saw also a difference between the engine block and the battery of approx 100 mV. Probably have to check the ground straps to the engine block and clean them.
Anyone who put a ground strap to the radiator and if yes, where?
Jeep manual states that there should be an external ground wire to the hydraulic cooling fan module. Other then the 2 wires going to the control solenoid (from which one should be ground), there is no external ground strap or alike. How is that on your jeeps (with the hydraulic cooling fan)

01grand 05-20-2012 10:58 AM

Interesting, I will have to check this out when I get home.


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Frango100 05-20-2012 03:16 PM

Re: Grounding of radiator
 
Here some interresting reading i found on the net.

Testing for electrolysis in cooling systems
A voltmeter capable of reading both AC and DC currents is required to test cooling systems. The meter needs to read zero to the maximum voltage of the system being tested in tenths of a volt. The meter leads must be long enough to reach between the coolant and the groundside of the battery. An ohm function of a voltmeter is very helpful to pinpoint areas of resistance in as electrical system that will cause an electrical current to ground through the coolant rather than the engineered electrical circuit.
Procedure
  • <LI style="COLOR: #0000cc">
    Attach the proper meter lead to the groundside of the battery, negative-to-negative or positive-to-positive.
  • Install the second lead in the coolant touching the coolant only.
  • Read the DC and AC voltage with all systems off. If a block heater is present, also take a reading with the heater turned on. If an automatic battery charger is present, as a standby system, also take a reading with this system running.
  • Read the DC and AC voltage with the electrical starter engaged.
  • Read the DC and the AC voltage with the engine running and all systems turned on: lights, coolers, fans, heaters, air conditioning, cell phone, two-way radio, including the phone and radio on both standby and transmit.
  • The above procedure will test a complete system except for an electrical current, which can be generated by the rear end transmission. This is particularly true with air bag suspensions, rubber pad suspensions and rubber-mounted transmissions. Any current generated will travel up to the drive shaft to ground through the engine coolant. Grounding rear ends and transmissions is strongly recommended.
  • Voltage of zero to .3 is normal in a coolant of cast iron engine. Such an engine will be destroyed with time by .5 volts, and engine manufactures are reporting .15 volts will destroy an aluminum engine.
  • The current will be AC if the problem is due to static electricity.
  • If the coolant shows an electrical problem with all the equipment turned on; turn off one system at a time until you finally turn off the system that stops the electrical current. When the current stops, this will indicate the electrical system causing the problem.
  • Be partially careful of starters. They can cause as much damage to a cooling system as a direct connection to an arc welder. This is due to the amperage present.
  • Always change the coolant if a current is detected. The electrical current will destroy the protecting chemicals in a properly inhibited coolant.
The following are failures that are not manufacturer defects and therefore not covered under warranty.
  • Improper Flush - Cooling systems require a through flush of the radiator, engine, overflow tank, hoses and heater core, failure to do so will lead to mixing coolants and contaminates and creating a deadly cocktail for the cooling system.
  • Corrosion – The correct coolant and distilled water mixture prescribed by the coolant manufacture of choice must be maintained. Water with high trace elements of minerals will create problems for aluminum radiators not normally seen in copper radiators.
  • Electrolysis – Electrolysis is the systematic removal of the protective layer on the inside of the radiator tubes due to improper grounding. Electrical grounding problems can stem from poor installation of aftermarket accessories or incorrect vehicle collision damages.

Frango100 05-20-2012 07:55 PM

Re: Grounding of radiator
 
Some more interresting material regarding ground straps:

Be suspicious of ground wires

Damage to ground wires is almost inevitable, even during a moderate collision causing $3,000 to $7,000 in damage. During the repair process, be sure to check your collision repair reference to make sure you know the location and connection points for all ground wires. When they are securely connected, the electrical path is well defined. On the other hand, any breach will cause the electricity to find the shortest, easiest, quickest path of least resistance. Particularly for electrical components or circuitry in close proximity to the radiator or heater'that path can involve the coolant itself.
If you have the occasion to check for electrolysis, use a digital voltmeter set for 12 volts. Attach one test lead to the negative battery post and insert the other test lead into the radiator's coolant, making sure the lead does not touch the filler neck or the core. Initially, you may see a surface charge that could be 0.7 volts or higher. It could take up to two minutes for this surface charge to dissipate. Only then will you be able to obtain an accurate reading. A voltage reading of 0.3 or higher indicates that stray current is finding its path to ground through the cooling system.
Cooling fans and A/C-heater fans are logical sources to check and eliminate early in your diagnostic process. Then check any non-factory accessories that have been added. Next, you can turn the ignition to the run position while turning various accessories on and off. When the meter's voltage jumps, you've found the circuit with a bad ground. A small amount of electricity normally flows through a vehicle's cooling system. In a properly grounded system, this small charge (less than 0.3V) is constantly discharged and no harm is done.
http://www.erareplicas.com/427man/co.../radiator2.jpgSerious problems with stray-current electrolysis can occur when the cooling system is not grounded or when an ungrounded electrical device is part of the vehicle's operating system. The cooling system then becomes a warehouse for this stray electricity, and the coolant turns into an electrolyte. This charged coolant is constantly searching for a ground or a way out of the system. When it finds a material it can attack (the path of least resistance), the coolant goes to work 'eating through' that material radiator and/or heater causing damage such as the following:
  • Solder-joint destruction
  • Aluminum corrosion and flake formation that clogs the system
  • Cast-iron corrosion that causes rust to contaminate the cooling system
Stray current also can be a problem with new, straight-from-the-factory vehicles. Back in 1986, Ford recalled approximately 19,400 vehicles to find a misrouted battery cable that could send a low-grade electrical current through the radiator, setting up an electrolytic action that could promptly ruin the radiator.
Frequently, by the time your customer realizes electrolysis is taking place, the radiator or heater damage is already done. Unlike a radio that frequently hums when a short exists or a resistor malfunctions, the cooling system does not emit an audible sound. To make sure that electrolysis doesn't start in your shop, let your technicians know the importance of reconnecting all ground wires.
What the future holds

For sure, you and your technicians will see more, increasingly complex electrical components and circuits in the vehicles that are brought to your shop for collision repair. As the price of mass-produced technology declines and consumer demand for convenience increases, the world of the possible will continue coming to the automotive industry. Many other ideas that are common in the aerospace industry remain to be transferred to automotive applications.
Soon water pumps will be electrically driven. Hybrid electric cars are already here. Battery-powered vehicles are on the horizon. These vehicles already operate at higher voltages and carry warnings about possible electrocution. A near-term change using existing technology is the 42V electrical system. Any electrolysis problems are likely to be the same, but the higher voltage is a good bet to cause larger and/or faster problems.
Tune in to new developments and stay current with diagnostic tools and procedures. Proper electrical grounding is just one of the many facets of collision repair that you need to know. Lack of knowledge is no ground for returning your customers' vehicles with incomplete repairs and easily avoided radiator and/or heater failures caused by electrolysis.

hoffmanestates 05-23-2012 08:43 PM

do a DIY. ground mod..... I performed this on my wrx. and it idles smoother.

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