Has anyone seen a water neck that is literally disintegrating before? Mine are corroded and covered with a bright green goo that I assume is congealed antifreeze. The sealing surface is degraded and along the inside edge missing in places. When I used my utility knife to gently try to get the goo off, chunks of aluminum were literally coming off. There are places on the inside that the material is half thickness or less. No holes yet but what would cause this?

don't worry I have already ordered new ones. I'm told they will be here by Thursday.

 

John, off hand it sounds like electrolysis (dissimilar metals reacting to each other). You have copper, aluminum and iron at least it sounds in your system. I see this all the time in marine engines but not usually in a closed automotive system. However if no/old antifreeze was used and possibly mixed with hard tap water (not distilled as you should) I could see this happening.

 

Electrolysis.....

 

I have only owned the truck for month and have really not driven it. Before that I can not speak to its life. I have flushed the radiator and block and put in a 50/50 blend of coolant and distilled water. I assume that in this scenario aluminum parts are the most susceptible to electrolysis damage. First is that a true statement and second what other parts do I need to work about? The radiator I assume but everything else is iron correct?

 

One more question. If I have replaced the fluid do I need to work about any other causes of electrolysis?

 

Check for good grounds throughout. Stray electrical currents cause electrolysis.

 

Actually you could have Electrolysis or galvanic corrosion, two different problems with similar result. Either way you are doing the correct thing. Purified water and good antifreeze will help with both. make sure you have a good gasket between dissimilar metals, aluminum water neck and cast iron block (helps with galvanic corrosion) and be careful when using something like a radiator for a ground as if the radiator itself is not properly grounded to everything else in the cooling system you could be setting up a possible Electrolysis path.

 

I suspect finding grounds will not be easy. The truck was converted to 12V by the previous owner so I am discovering new wiring on a daily basis. I should probably try to do a layout so I can picture what is going on.

 

You don't need to "find" them, you need to install them...you can never have too many bonding straps between the engine/frame/cab. One area that many people miss is the radiator. Most radiators are shock isolated with rubber pads...this makes the radiator electrically isolated from the rest of the truck system. Find a place to attach a bonding strap to the radiator and run it to the frame as well. As folks have already said, dissimilar metals are not good bedfellows, especially when they are not grounded to one another. Good luck...

 

I purchased sacrificial zinc anode rods from a marine supply. They come mounted to various NPT (and other) threaded brass holders that will readily replace a radiator drain or water jacket plug. Check 'em during the annual once-over.
Many places carry them:
http://m.autozone.com/autozone-mobil...n2?switch=true

(Cellphone link).

 

The best antifreeze spec for multi-metal systems is GO-5, which is what Mercedes and BMW spec. Prestone and others sell GO-5 spec, I buy it at NAPA. It's only a couple bucks more a gallon.

 

X2 on what ^^^^ he said