Dear Jim,

I have a 2005 Dodge Durango that hasn't given me any major trouble, although I did have a freeze plug replaced in it about four months ago. There's no problem with the replacement, but just last week I found that another one of the plugs had gone bad. I've never had a freeze plug replaced until I got the Durango. Why are these plugs going bad? Is it a common problem with this vehicle?

--Chad Billings

It shouldn't be a common problem with any particular vehicle, bro, but it will definitely happen under the right -- or wrong -- circumstances. As you know, these plugs are installed on the engine coolant lines, and they're intended to provide an important service in protecting your engine when the outdoor temperature dips below zero. In the ugly event that water freezes in the radiator, they're made to pop out and prevent your engine block from being damaged by the expanding ice. These are cheap but really useful little inventions.

The thing is, these plugs are normally made of tin, and tin rusts. I'll bet you didn't have any antifreeze coolant in your vehicle for a period of time, which is why these plugs corroded and needed to be replaced. Remember, not only does antifreeze lower the freezing point and raise the boiling point of your engine coolant, but it contains valuable rust-inhibiting ingredients. If you're just using water, the inhibitors aren't there and those tin plugs are eventually going to rust.

The first thing you should do is make sure you have the recommended 50/50 mix of water and fresh antifreeze in your coolant system. It's the only way to go, for all the reasons mentioned here. By the way, use the yellow antifreeze -- not green, orange, pink, blue or any of the other color-coded versions. Your Durango's engine is only compatible with yellow because that's what it was built to handle. The other antifreeze types may contain other additives that can actually damage your engine in the long run.

Anyway, once the coolant situation is taken care of, brother, have all those tin freeze plugs replaced with plugs made of brass. They do the exact same thing, they're not very expensive and brass won't corrode nearly as fast as tin.

Buffalo Jim, owner of Allstate Auto & Marine Repair in Las Vegas, writes a weekly column. Send your automotive questions to him at buffalojim@lasvegasniftynickel.com. If Jim picks your question to answer in Nuts & Bolts, you'll also be the proud recipient of a deck of official Buffalo Jim playing cards, presented in a classy, tin box bearing his hairy image.