Alloy radator cracks

[tinkera Member Find all posts View Profile Close tinkera]

just returned from hols.Checked under bonnet saw that overflow tank was well down.Dropped down to local machanic told me tank core was leaking.Say's common problem electrolises or bug acid.has anyone had similar problem?.Car has only done 78k.BTW check prices to fit new one its an eye opener :shock:

[damonat Advanced Member Find all posts View Profile Close damonat]

Re: Alloy radator cracks

see the below link for this subject.
yes it has happened to a few of us, me included.

viewtopic.php?f=12&t=4802

[tinkera Member Find all posts View Profile Close tinkera]

Re: Alloy radator cracks

Hi guys. just had new radator fitted today,installer tells me i have .5v current running through tank ,witch will cause electrolosis inside tank causing alloy to brake down.Also had a line of locust strikes above condencer tank, same spot as leak.Put earth strap from tank to body still had .5 v in tank. :? Going to try earth tank to engine tommorow and see how we go.Has anyone got any ideas other than this :?:

[Billy Junior Member Find all posts View Profile Close Billy]

Re: Alloy radator cracks

Hi guys. just had new radator fitted today,installer tells me i have .5v current running through tank

How did you check this stray voltage?

[adrian5800 Advanced Member Find all posts View Profile Close adrian5800]

Re: Alloy radator cracks

Hi guys. just had new radator fitted today,installer tells me i have .5v current running through tank ,witch will cause electrolosis inside tank causing alloy to brake down.Also had a line of locust strikes above condencer tank, same spot as leak.Put earth strap from tank to body still had .5 v in tank. :? Going to try earth tank to engine tommorow and see how we go.Has anyone got any ideas other than this :?:

If the aluminium core is insulated from the chassis you won't get electrolysis occurring. 0.5V is insignificant anyway and by the way voltage isn't current..

Hi guys. just had new radator fitted today,installer tells me i have .5v current running through tank

How did you check this stray voltage?

The generally accepted way is voltmeter +ve probe in the coolant and -ve to earth.


Regards

Adrian

[tinkera Member Find all posts View Profile Close tinkera]

Re: Alloy radator cracks

Thanks for your replies. Installer tells book says .03 is max.You are right, meter neg is placed on battery neg terminal pos.is placed in radiator coolant carefull not to touch side of tank.I've since heard dumping coolant then refilling with demineralised water and new coolant.Tap water has to many minerals in it. I think i will try this sounds right.I'll keep you posted. :idea:

[Billy Junior Member Find all posts View Profile Close Billy]

Re: Alloy radator cracks

Hi guys. just had new radator fitted today,installer tells me i have .5v current running through tank ,witch will cause electrolosis inside tank causing alloy to brake down.Also had a line of locust strikes above condencer tank, same spot as leak.Put earth strap from tank to body still had .5 v in tank. :? Going to try earth tank to engine tommorow and see how we go.Has anyone got any ideas other than this :?:

If the problem was caused from electrolysis I would have thought that the radiator fitter would have found the source of the stray voltage before fitting a new radiator :!:

Anyway you need to sort this out asap.

I would start by checking that all of the grounding points in the engine bay (this should be done during servicing anyway) especially the engine and starter motor grounding points.Check the cooling system voltage before you start the car then during starting,running,switching lights on and other accessories on one by one.

Some people say that some coolants holds a small charge especialy if it has been topped up with tap water . Cooling systems should be flushed and checked for stray voltages with demineralised water only, before adding coolant to get a accurate reading.

[tinkera Member Find all posts View Profile Close tinkera]

Re: Alloy radator cracks

Hi billy,just read your post great .Do you have some experience with this :?: Have not had a chance to try anything yet what would you try first.Installer contacted auto elec. while i was there all he could suggest was earthing tank to engine because we had allready earthed tank to body.BTW volts were still there motor running or not.

[lawrance Senior Member Find all posts View Profile Close lawrance]

Re: Alloy radator cracks

I'm scratching my head as I'm reading this - I thought that the suggestion from the auto sparky to earth the engine to the radiator seems like the complete WRONG thing todo.

A current flows when there's a path for it to flow. Currents will flow when dissimilar metals are brought into contact with one another, causing galvanic corrosion (e.g. Old Land Rovers with aluminium door skins and steel door frames = bad galvanic corrosion of the steel)

So the solution when having dissimilar metals put together, e.g. a D4D cast iron block and an alloy radiator would be to keep the two isolated from one another. Hence only rubber hoses connect the two together and the radiator is mounted onto the body via rubber grommets. So there will be a voltage potential between the two, but no electrons will flow because there is no path for the electrons to travel.

By grounding the radiator to the engine, a circuit is created, and you can watch the galvanic corrosion process to begin.

So I say it is OK to have a voltage, because that's normal. As long as the radiator is not grounded in anyway, that voltage is not going to matter because there won't be any current flow.

[MickL Addicted PP Member Find all posts View Profile Close MickL]

Re: Alloy radator cracks

Depending on petrol/diesel it should be around $450-550 for a complete new radiator. Try "Nationwide Radiators" online.

By grounding the radiator to the engine, a circuit is created, and you can watch the galvanic corrosion process to begin

On this point you are correct, you should never ground the radiator.

So I say it is OK to have a voltage, because that's normal. As long as the radiator is not grounded in anyway, that voltage is not going to matter because there won't be any current flow.

I wouldn't say it's "OK" it's a symptom of another fault and if present will effect other components as well (Heads, thermostat housings etc). Here is some info I got from TAFE:

WHAT IS ELECTROLYSIS?

Electrolysis is the result of electricity flowing through your cooling system and causing an electrochemical charge across the aluminium. This results in rapid corrosion and severe damage to the components in your cooling system including discoloration, pitting, flaking, and pinholes. Most common in late model vehicles, electrolysis will usually occur if there is a defective or missing ground on one of the numerous potential electrical sources.

HOW CAN I TEST FOR ELECTROLYSIS?

To test if your cooling system has been affected by electrolysis, you will need to test the voltage in your cooling system. The first step is to connect the negative lead of a volt/ohm meter to the battery ground. Then, carefully insert the positive lead of the volt/ohm meter into the coolant inside the radiator without contacting the filler neck. If the result is more than 0.10 V, this indicates that there is an electrical current flowing through the system. Continue to check the voltage between the coolant and (1) the engine (2) the frame by touching the negative lead to each respectively. Repeat test with the positive lead touching the radiator instead of the coolant.
A simple and usually effective way to try and determine the faulty electrical source is to conduct this test with the engine running and all vehicle accessories on. Have a friend or assistant systematically switch on and off components of the car as you monitor the meter (in some instances, fuses need to be removed in order to switch the accessory off. You may also want to test with the ignition off). If voltage drops when disconnecting an electrical circuit, that circuit represents a likely electrical source.
WAYS TO PREVENT ELECTROLYSIS:

Unfortunately, only the careful monitoring and proper maintenance of your cooling and electrical system can really prevent electrolysis from destroying your system. ALWAYS make sure the radiator is not used as a ground and that all components are functioning properly. Periodically test your system and check for any discoloration or pinholes – especially around the tube-to-header joints and tubes near the centre of the core by the electric fan mounts.