Freeze plug problems
 

I noticed I had a coolant leak under my ss396 Camaro that I just had at MCACN in November. I didn't rebuild the engine because it only had 41k on the rebuild. I did change all the freeze plugs because I had one leaking. I used the green coolant 50/50 mix with tap water. I've probably only driven the car 3-400 miles since the restoration. I now have three freeze plugs leaking. The one pictured is one I just removed. These were brand new less than a year ago. The battery is never left connected when in the garage.

I sent this picture to my friend Larry (lbnaz) & he indicates that it's most likely a ground problem causing electrolysis. I guess I need to check my grounds but I wanted to ask if anybody has seen this & maybe, where was the problem found?
Thank you, Joe

I always use distilled water when I mix with new green anti-freeze. Too much crud in the tap water here. Maybe the stuff in the tap water is reacting?

It never has before but once I resolve the problem I'll change everything out. I will have the old stuff tested that I pulled out....thank, Joe

Possibly, the freeze plugs have become a sacrificial anode. Brass or stainless-steel plugs may solve the problem.

https://www.corrosionpedia.com/defin...rificial-anode

Seems like all my engines have brass freeze plugs …

Normally that's what I do except I was going for as close to original as possible. Do you know how hard it is to find 1-3/4 steel freeze plugs without writing all over them? Not fun....Joe

I just dropped off a coolant sample to Caterpillar. They will send it to a lab & I should get results back next week. 20 bucks (cheap) for lab work but I can't lose that engine. i'll keep checking for ground issues....Joe

----All my marine engines have brass freeze plugs, even if the boats are in fresh water. My incoming water is super purified (even de-ionized) before it goes anywhere in the house or garage, so no problem there!.....Bill S

What he said.

Your coolant that is now in the engine will need to be fully flushed out , it is probably highly out of the PH range. Does your shifter cable seem to hard to move? If it is a bad ground it will try to use it as an alternative.