Continuity mistake: Al enters the house at 3am with Lucky. It is sleeting outside and there is snow all over the front and backyard. Later that day, Al is in the backyard, no snow to be seen, and grass and bushes in full bloom.
Continuity mistake: In this episode Al is building a dog house for Lucky. In Season 9 episode User Friendly, we are shown that there already is a dog house, which has electricity and a light.
Answer: It was one of the hoses connected to the engine, nothing specific, but to indicate that Al tampered with the vehicle.