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| twr7cx |
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Anyone able to educate me further on stray current, how to test for it and how to get rid of it?
I just put the positive end of the multimeter into the coolant and the negitive on the body and it read 260mV - is that fine or an issue? I'm wanting to install a PWR radiator, but I've been told they won't last long if their's any stray current. |
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| n00bus m@x1mus |
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A stray current can result from a faulty or out of range coolant temp sender or coolant level sender but also current can be amplified by a high corrosion level due to different metals contained in cooling systems such as mild steel/alloys/brass/copper/aluminium which mixed together creates electrolisis between each other.
Check again with the battery disconected and engine stopped and compare to engine running and if there is no change it will be a current stored in the coolant by electrolisis. |
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| twr7cx |
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how do you get the current out if it's stored in the coolant by electolisis? drain, flush and refill?
will check tonight. |
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| snap0964 |
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The temp sender shouldn't cause any electrical disturbance - it's simply an insulated variable resistor. Coolant may have some additives that may conduct electricity, but it would be very minimal as it is mainly glycol. Distilled water should be used.
All you can do is change the coolant regularly. What you can do is mix up some coolant in a dish, put 12v through it with a meter in series measuring current - see what you get for interest sake. You could also check and make sure the radiator is electrically bonded to the chassis.
_________________ 96 XH Longreach 'S': LPG, Alarm, 3.23:1 LSD, Cruise, Trip Comp, ABS, Power Windows, Mid Series Dome Lt, Climate Ctrl |
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| EL__Fairmont |
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Maybe add a few more earths like one to the radiator support panel? There is only that little gauge earth wire from the battery to the 10mm bolt near the coolant reservoir. That is the only body earth I have on found on my el falcon.
_________________ 97 EL Fairmont 4l OHC .Silver. |
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| n00bus m@x1mus |
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twr7cx wrote: how do you get the current out if it's stored in the coolant by electolisis? drain, flush and refill?
will check tonight. The only sure fire way to delete all electrolisis is to dismantle the engine and cleanout and flush all the water jackets and cooling system. as this is not an option many want to take u could try a high grade coolant flush and remove radiator and thermostat housing and waterpump (if ur keen bang out the welsh plugs and replace too) and visually inspect for corrosion, clean up or replace corroded parts and flush system with clean fresh water, operating the heater core in the dash as well. Then reassemble and use a high grade coolant recommended for ur exact engine as there are alot of differences between coolants and brands out there, check ur user manual for a guide. Addition earths will do nothing at all as it has nothing to do with the 12v electrical system of the car it is electrolisis, same way a battery with and acidic fluid and lead plate generates current, or when u plate a metal with another kind or metal (ie chrome/nickel/zinc/galv ) Beside how can u supply additional earth to the coolant if it is is constant contact with the internals of the engine which is earthed anyway. Try the above method and all should be well. |
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| snap0964 |
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Actually, the car's electrics is quite important.
snap0964 wrote: You could also check and make sure the radiator is electrically bonded to the chassis. With falcons and their plastic tanks, the mounts won't bond it to the chassis - earlier cars did bond to the chassis through all metal construction, but you'd want the extra bonding of the engine block so the electric charge won't all discharge to chassis through the radiator.
Looks like what you've found with the meter reading is normal, see http://www.search-autoparts.com/searcha ... ?id=154932 .
_________________ 96 XH Longreach 'S': LPG, Alarm, 3.23:1 LSD, Cruise, Trip Comp, ABS, Power Windows, Mid Series Dome Lt, Climate Ctrl |
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| twr7cx |
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cheers for that. would seem I'm under what that article recomends, so all should be good.
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| n00bus m@x1mus |
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^^^^^ This is fair enough but u would have to put in place a lot of earth to be of less resistance than the block has at its earth strap so any current discharge will be thru the block earth strap and not thru the radiator earth. Any way if u did manage to provide less resistance at the radiator it would become the most vunerable point for corrosion, as all energy would be transmitted to the earth point so would the corrosion and would quickly eat out a wafer thin aluminium radiator than a cast iron block.
The replacable components of a cooling system (ie the thermostat housing/water pump/welsh plugs) are all made of a lighter, more sacrificial metal so as to concentrate corrosion at these parts, saving the more irreplacable parts such as alloy heads and intakes and such. |
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| EL__Fairmont |
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I only can find 3 earth wires on my EL.
1) Battery neg to engine block 2) battery Neg to coolant reservoir support bracket 3) ECU earth strap to passenger kick panel frame That article says that there is 10-20 earth points in most modern cars? I know my old EA falcon had a strap from the block to the floor left of the gearbox. EL doesn't have this!! cheers...
_________________ 97 EL Fairmont 4l OHC .Silver. |
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| snap0964 |
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twr7cx wrote: cheers for that. would seem I'm under what that article recomends, so all should be good. Yeah, change your coolant regularly, make sure your earth straps are good - you'll find the design of the std setup to be fine, otherwise you'd of heard of E series issues with electrolysis. Obviously, don't earth any extra electrical components through the radiator.n00bus m@x1mus wrote: The replacable components of a cooling system (ie the thermostat housing/water pump/welsh plugs) are all made of a lighter, more sacrificial metal so as to concentrate corrosion at these parts, saving the more irreplacable parts such as alloy heads and intakes and such. Replacement welch plugs are brass AFAIK, and brass is more noble than aluminium or alloy.
_________________ 96 XH Longreach 'S': LPG, Alarm, 3.23:1 LSD, Cruise, Trip Comp, ABS, Power Windows, Mid Series Dome Lt, Climate Ctrl |
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| twr7cx |
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snap0964 wrote: Obviously, don't earth any extra electrical components through the radiator.
lol. didn't plan on. |
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| n00bus m@x1mus |
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snap0964 wrote: Replacement welch plugs are brass AFAIK, and brass is more noble than aluminium or alloy.
This is exactly right, if the welsh plugs were made of a different metal like for example an alloy then they would corrode out same as the thermostat housing as well as starting electrolisis corrosion in the water jackets leading to pin holes in the bores and side walls of the block. All metals are strategically placed in order in a cooling system to control electrolisis and to divert corrosion to more managable places. the pH level of coolant will always cause corrosion and with the addition of multiple metals it is a bad combination to start with, so this is why car manufacturers recommend a particular brand and concentrate of coolant so as to keep the pH balance right. In ur case of fitting a fully aluminium PWR radiator i dont think this will be a problem as the factory radiator also has an aluminium core so u will not be changing anything here. If ur current level is lower than scary than go for gold mate just keep the bugs out of it 
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