Thread: New Radiator - Leaking !

Ah great, another thing to watch out for. I would never have guessed.

My earth straps are good, but this possibility makes me uncomfortable because I don't understand it.

Are you saying that if an earth strap to the engine is bad then anything that uses the engine as an earth will potentially get some negative current through the coolant from the radiator assembly? Or would it be a positive short to the radiator assembly that runs out through the radiator -> coolant -> engine...



What about a faulty temperature sender/switch that sits in coolant?

My radiator sits on rubber grommets top and bottom theres a good chance it is isolated from the support that is ground to chassis by its mounts so if a positive short hit the radiator it would probably look for ground throught the coolant...


am I close?

Manic was there any chance the fan cable tied to the rad was electrically grounding on the fins , that would cause the problem, for sure.

in my old job they were anal about earth leakage

I would NOT earth the radiator , it should be rubber mounted / electrically isolated , And if you have one I would REMOVE your Low coolant level alarm , that puts a stray current into your coolant top hose, (the type that works by putting an electrical current into your coolant in the form of a metal probe in the top hose bleed hole)

The way I see it if the radiator is electrically isolated (rubber mounted) there will be no reason for it to become a sacrificial anode.

Earth everything else, over & above what LR do,

Landrovers are notoriously bad for Earth faults,
ever pulled an old Landy apart, the white powder that forms under a bolt head is aluminium oxide caused by electrolysis and it is an excellent electrical insulator, so just because an alloy panel is bolted to another metal part don't assume its earthed.
Ive got redundant earthing on mine in the form of a seperate earth bus that bonds the loom in various places, firewall, roof, guards, tub , chassis, engine, bullbar , gearbox, ECU & battery, At least I'll be OK if I get hit by lightning

edit, I just found this, interesting reading,

http://www.qldstreetscene.com/forums...ium-radiators/

Excellent info in that post, thanks.

I do have a coolant level sensor in the rad plug that works on conductivity. And it is possible that the electric fan on the rad caused the issue with a short/current leak. Only recently the fan would go on but the indicator light would not.... Considering it failed so abruptly it may have been a hard and fast short when I was working around that area doing the coolant drain and top up. I'll be sure to improve the fan set up when I re-install.

Hopefully any coolant level sensor voltage in the system is negligible. Its a nice set up as it is and I'd rather not butcher my header tank with a float switch.
I'll find an analogue multimeter and do a current check with distilled water when I get a water tight rad sorted. I'll post results. There must be quite a few people on here with electric coolant sensors in their aluminium rads.

Maybe I should just get a copper core rad considering how rapidly an aluminum one deteriorates when current goes astray.

Originally Posted by goingbush

I would NOT earth the radiator , it should be rubber mounted / electrically isolated ,

Don, I would've thought the same except the Patrol rad was totally isolated, rubber mounts top and bottom off the plastic tanks and it went through....

Given that most alloy Radiators have plastic tanks which are in themselves insulators , Is it possible that the current,or some of it, is "leaping" from core to core? The fins may not be a very good electrical bond with the cores and that is how the electrolysis is "eating" the alloy away? This earthing game and stray current can do some strange things at times, and is not always predictable.
That QSS forum post has some very interesting information, even if some of it just commonsense.
Cheers Scott

sacrificial anode ??

http://www.summitracing.com/parts/FLX-32060/


more info and a idea of what voltages are harmful, http://are.com.au/feat/techtalk/straycurrent.htm

and from the Jag club, some good info
http://www.jaguar.org.au/cooling-system-tips.htm

Just out of curiosity I got my multimeter out


negative lead on block (for all readings)

positive lead on low level alarm terminal in top hose.

Alarm wire disconnected
engine off .01v
engine on .01v

Alarm wire connected , ign on 1.25v

now the unexpected result, ignition off
multimeter lead clipped to radiator core -ve 0.2v
with ign on the voltage polarity on the radiator core changed to +0.2v !!!
apparantly from reading links in prev post the safe level is .05v

the voltage on the radiator core was not affected when I disconected / connected low level sensor alarm wire

when I shunt the rad core to earth the voltage reading falls to zero

with probe in coolant reservoir .01v engine running

not sure what to make of these results

I still have the original (AFIK) alloy radiator with plastic tanks,
its electrically insulated via rubber mounts & when I replaced the hoses & coolant prior to this trip I inspected inside radiator (borescope) and it looks corrosion free

will leave well enough alone and wont be earthing the radiator core, to me this will give any stray current in the coolant a direct path to earth thru the core, and as there is voltage in there even with car turned off it will be eating away at radiator 24/7

Wouldn't the radiator fluid which is mainly water be an earth straight to the motor??