I have a new to me 2000 disco 120750 and have been hearing this noise it sound like a vacuum motor running under my hood I would have to say its coming from the passenger side. It happens after I shut it off it sound like I turned off a vacuum under my hood, till today turned the key and sounded like I had a hoover vacuum under my hood?
What is that?

 

Good news it just made the noise while I had the hood open its the SAI PUMP I looked it up on my manual, but what the heck is a SAI PUMP? FYI my manual just shows a picture's no info!

 

That would be the secondary air injection pump. Part of your emissions control system. That's about all I know about it.

 

Ok this is what I found out...."The secondary-air pump supplies extra oxygen when starting from cold, thus ensuring that any unburnt exhaust components are combusted in an afterburner. This afterburning leads to a direct reduction in emissions. In addition, the heat produced warms the catalytic converter up more quickly to the high operating temperature required for converting emissions. The secondary-air pump thus makes an important contribution towards clean engines in the future"

So will this mostly effect me during cold starts? I know it needs to be fixed but I had a death in the family and need to drive to AZ from ID soon!! So really what i'm asking is will this cause me and my family spend the day on the side of the freeway?

 

No, it is not going to leave you stranded. It is completely an emissions thing and the engine can run without it, but will put out more emissions until the cats get up to temp.

 

Ya thats what I hoped to be confirmed! thanks AK ROVER!

 

Clean the filter to it.
Pull it out, wash it, dry it, put it back.
Let it air dry.