Hi, I checked my car today and found an oil leak, and I think it's that black hose. Does anyone know where that oil is coming from and where I can buy a replacement? I'd appreciate your prompt response, as I wouldn't want my truck to get damaged.

 

Degrease the pipes, hoses and frame members...get it all clean and see where the leak is coming from before buying parts.
If it's the lower, metal pipe, it likely has taken 16 years of hits and finally sprung one....just replace it.
If it's the hose, replace all hoses...don't patch.

Vehicle details help:
Mileage on vehicle and of any major repairs, bought new or used...general condition or history etc.
What kind of power steering fluid is in it?