In marine issues, ships use a floating ground in all of their electrical connections, which means they must run a ground wire in the circut to complete the circut and is not normally attached to the box or ships hull. This is common with all 3phase, single phase and dc circuts.
Ships like most boats also use a zinc anode to attract the electrolisis that a hull would normall incur being in the water. On small water crafts such as out board motors, many will make the mistake of painting over the zinc anode, thus causing it to corrode and eat the metal surface.
Notice in this pic, the (silver colored)zinc anode used just above the prop.
To answer your question, the purpose for grounding the radiator and oil cooler makes little sense because in an automotive engine system, the frame unlike in marine applications, is also the dc ground tied directly to the battery. Also the rectifiers built into most alternators now, which takes the ac developed from the alternator and passes it through as a DC voltage which is tied directly to the dc battery which acts like a filter cap that keeps the dc clean from any ac ripple developed by the alternator which rides on top of the DC vcc.
There is a small cap mounted on the outside of the alternator that provides ac filtering which is tied to the same ground.
Also In marine applications,electrolysis is a common form of corrosion in marine environments. It occurs when two (or more) dissimilar metals are brought into electrical contact under water. One of the metals becomes the anode and corrodes faster than it would all by itself, while the other becomes the cathode and corrodes slower than it would alone. Either (or both) metals in the couple may or may not corrode by itself (themselves) in seawater. When contact with a dissimilar metal is made, however, the self-corrosion rates will change: corrosion of the anode will accelerate; corrosion of the cathode will decelerate or even stop.
So to ground radiators and such should not make a bit of difference as for electrolisys potential between those metals due to grounding, and since they are not normally touching dissimular metals, I see no way for this to make or break electrolisys any different as a circut.
As ED P. pointed out, the best way to eliminate any concerns is to watch the acidity levels or make a point to flush and change the antifreeze at recommended intervals therefore there is no electricly charged chemical re action due to the breakdown of the glycol. BTW, In all my shrimp boat applications, they too have radiators on their engines and they too have to watch for acidity like on diesel trucks, which carries a common ground to their engines and frames. Both can experience the same exact problem with leaking liners in their engines due to electrolysis. This is EXACTLY WHY you SHOULD BE USING a product such as the clean and cool.
One other thing,... read in your owners manual or check with dealer on any diesel engine, if you ARE NOT using some form of additive in your coolant, IT CAN VOID NEW ENGINE WARR if a liner leaks!!!.
Hope that helps.
[ February 22, 2003, 08:20 PM: Message edited by: BOBISTHEOILGUY ]
