I have a 2000 Disco II with 136k on it. When I start the car, a lot times I hear a funny noise coming from the passenger side of the engine. The rover always idles at about 1,200 - 1,300 rpms for maybe 10 or 15 seconds and then the rpms go down to about 800. I don't think there is any problem there...

The sound I hear does NOT coincide with the rpms. It is kind of a high pitched electric hum. Not too high pitched though. Almost like the sound a microwave makes when it's on. It goes usually for only 5-10 seconds and then stops. I don't really hear it ever do that when I am driving, and only very irregularly do I hear it sometimes when I am stopped at light, or just sitting idling. Any idea what this is?

 

Was your car from California? Sounds like you MIGHT be talking about Secondary Air Injection. Shouldn't come on while driving and stopped at a light, though, unless it's still on from the cold start.

 

Actually, yes. I think the Rover was originally purchased in Cali... at least that's what the Carfax shows. It really only comes on when I first start up. I can recall maybe 1 or 2 times it came on while I was sitting at a light or stopped for a while. I live in Reno.

 

Does it almost sound like a hair dryer? If so that could be your SAI on it's way out.

 

1. The truck makes those higher rpms to warm up the CATS ASAP - normal.

2. The SAI makes the hairdryer sound on cold starts, it also wants to shove a little air in there for some "after burner" effect and reduce pollution just at startup. There is a filter in the pump, but noise usually means the end is near. May not find a lot of them in salvage yard near you, but we have had recent posts from a dismantler in California....

 

Thanks everyone for the help. It does sound like a haridryer, so I believe it is the SAI. Any idea how long it takes for it to go out?

 

After looking at the RAVE manual, the SAI looks like a pretty easy fix. I believe this is what is causing the noise as it is in the exact location that I can hear the noise coming from.

On Roverlandparts.com they have an SAI unit for $225.

From what I can read, the SAI only helps control emission on start up. If it fails will it affect anything other than emissions?

aka, does this need to be fixed right away if it goes out?

 

Might check with a dismantler. Seems like if plumbing is OK, the unit might make a code appear. But it does not hold the power of say an oil pump, etc.

 

check this out:

SAI faults ? - DiscoWeb Message Boards

I provide no warranty for this link.

 

bballjames, although these guys can point you in a better direction than I can, I have experienced this problem before. Its a little hard to describe the sound I think you're talking about, but you might want to check the terminals and connections at your battery and make sure everything is clean and tight. I had a similar noise in my 2003 Discovery II and while I was poking around I realized that the one of the leads was loose. Once I tightened it up the noise disappeared and everything was back to normal. Its worth a look.