Stray Current

[Nic_A31]

Hey guys,

I've been struck with an absolute head-f**k of a problem that's incredibly risky to keep running, and I need to sort it this weekend.

I don't have the car all day Saturday, and I need to do a 65km round trip on Monday.

She's producing a stray current while running.

Starts off small at around 0.10v and as the temperature increases it settles at anywhere between 0.60 to 0.80v.

Being an all alloy radiator I can't risk running this any longer, as it's already been on the go for at least one week.

I only came to realise today that there is a current in the coolant.

I checked the main earth lead of the battery, added another earth from the terminal straight to the chassis, and another 2 leads off the motor onto the chassis in the engine bay, but the current persists.

I completely disconnected the ECU loom from the ECU,

completely disconnected the starter motor wiring, alternator wiring,

I completely disconnected the battery and took it out of the engine bay, only to notice that the car STILL somehow has current in it.

As the temperature drops, the current does also, very very slowly.

Has anybody here had this issue before?

I don't even know where to start looking. Stressing big time.

I'm not keen on simply attaching a strap from the radiator to the chassis to earth it out, as this will have a two fold effect and actually promote somewhere for the said current to go, directly into the radiator, rather than via the coolant.

Edited August 5, 2011 by Nic_A31

[Shazza24]

Have you seen this... it may be in relation to your alloy rad but i personally don't know. GL and sorry i cannot help more....

http://www.rondavisradiators.com/tech.htm

[wlspn]

I feel your pain!

After having & repairing 6 odd coolant leaks in about 4 months I realised something else was going on & checked coolant to find it reads almost 1 volt through multimeter.

All earths, etc are clean.

Currently in the process of ripping my car apart, redoing ALL wiring, cleaning all earths, adding extra earths, etc to try & sort the problem.

Have you tried flushing old coolant & replacing with fresh stuff?

Let me know how you get on...

[Dan_J]

must be me but just i read that and thought " hmm your coolant/ radiator has voltage, so? is that a bad thing? "

put rubber washers/stoppers from clark rubber from anything that the rad is mounted with to the car body? then again the coolant goes by the intake manifold which is grounded so it would still transfer to the rad.

again why is this bad?

[Nic_A31]

Electrolysis. It causes corrosion and eats away at the insides of alloy radiators.

Can chew our radiators in a matter of days.

Radiator is sitting on brand new Nissan rubber mounts top and bottom, but like I said I'm reluctant to go adding any more earth straps directly to the radiator, that can do more harm than good.

[toffy]

where are you getting your water from??

[Nic_A31]

Everywhere.

Local guys at radiator shop put de-mineralised water in it when diagnosing why temp. sensor wasn't triggering the fan relay.

I flushed with tap water and went fresh pre-mixed coolant.

Flushed it again today with tap water (ran probably 50+ litres through it) and radiator flush.

Bit of an update,

I've ran an extra earth from another bolt on the engine mount straight to the chassis rail.

Ran extra lead from negative terminal on battery straight to chassis rail.

3 from motor itself to chassis.

1 from gearbox to chassis.

1 from diff to chassis.

1 from cradle to chassis.

STILL got current in the water that sits at around 0.80v when at normal operating temperature.

[wlspn]

When you removed your battery altogether how long did you wait before measuring voltage again?

Will take quite a while to dissipate...

Try again & wait a long time to see if voltage drops to 0/reasonable specs.

If that ends up being OK, run car with EVERYTHING on then turn things off one by one, waiting 5 mins between each to see if voltage drops.

Can also try removing fuses one by one...

Do you have many aftermarket electronics such as alarm, turbo-timer, EBC, gauges, amp(s), etc?

[Nic_A31]

I let the car sit for an hour without the battery and the current dropped at the same rate/speed as when it drops with the battery connected.

I also disconnected every single fuse one by one, and noticed no differece.

I put a stock radiator in today, and

the hose itself registers a reading of 0.10v-0.15v.

The coolant registeres between 0.03v-0.04v.

WTF ?

Next thing I'm doing is rubber lining both tanks on the alloy radiator and putting that back in, see if maybe it was the mounts that was causing trouble.