Can an egg really help plug a radiator leak?

Dear Car Talk

Dear Car Talk | Jan 01, 2008

Dear Tom and Ray:

Following an end-of-semester party, my university English students were headed home for the holidays -- sober, at least for the moment. One of the girls said she was concerned about driving home in the snow with a radiator that had been leaking. The response from her classmates (remember, these are English students) was to put an egg in the radiator. Somebody grabbed a couple of eggs from my refrigerator, put one in the radiator and gave her the second to keep in the car -- I hope not for long. All my students responded to the idea with an: "Of course! Why didn't I suggest that?" attitude. I never thought to ask if the egg went in whole or if it was broken. The only possibility my husband and I could come up with is that the egg would cook in the hot radiator and be pulled toward the leak. Neither he nor I am mechanically or egg inclined. Were they messing with my mind after a brutal semester by confusing me, or is this a valid short-term solution to a leaky radiator? And if so, how does the mechanic remove the cooked egg? -- Leslie

RAY: It's a legitimate last-ditch potential solution for a leaky radiator, Leslie. But I would emphasize "last-ditch" and "potential." It's something you might try on one of my brother's heaps, not on a car that's in good condition.

TOM: It would be like, if you didn't know the answer to a question on your English final exam, you could quote Emily Dickinson. Would you get the answer right? Probably not, but since you've got nothing to lose, it can't hurt.

RAY: The egg works -- when it works -- exactly as you describe. You do have to crack it open, Leslie. You pour the contents into the radiator. Then the egg cooks and partially solidifies, and is pushed toward the leak, where it might -- if you're lucky -- lodge in a small hole and plug it up. At least for a while. And how do you get it out? You don't. Which is why we don't recommend this for a car that still has useful life in it.

TOM: Right. Because the egg can also plug up your heater core, for instance -- at least the yolk can. So I'd stick with the recommendations of the country's top cardiologists and use only the egg whites, Leslie.

RAY: Actually, instead, we'd recommend one of the many commercially available products that work on the same general theory -- only better. They use some kind of proprietary compound that dissolves in the coolant and then hardens when exposed to the air at the leak site. For all we know, those things have eggs in them, too!

TOM: But if you can afford the four bucks, we'd recommend a can of something like Stop Leak or AlumAseal rather than something that came out of a chicken's behind.

RAY: And what would you call OUR advice?

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