I bought a 2003 Disco 60,000 miles very late model vin after the oil pump.
I have test driven a bunch of these and none of them ran as good and strong as this one. I was against this purchase because of fuel mileage and maintenance issues but caved in to my wife's desire with her recent poor health. I have to say this truck is growing on me. My question is what makes all the racket when you first start the truck, it high idles and makes a lot of noise. Not valve clatter or anything nasty but just a very loud warm up high idle noise. It sounds like the electric fans all come on at the same time. It has been warm here in Chicago and I am thinking maybe the ac was left on and maybe the fans are just loud? After the idle kicks down the truck sounds great, and if I restart the warmed up truck it is quiet. It does not scare or bother me but my wife wanted to know what in the heck was all the initial noise. Anyone?
I can have my kid video the noise and put it on you tube. Feeling kind of stupid posting this but I am curious. I do all my own work on my cars brakes oil changes etc I am just puzzled by this.
Ernie

 

If the AC was left on then they will kick in when you start the engine. Also if your fan clutch is not releasing properly your engine fan will be turning full speed at start up which will also make a lot of noise. With the engine cool try to spin the fan by hand. If the clutch is locked up the fan will be extremely tough to turn if it turns at all. Replacing a bad fan clutch will help with your fuel mileage also. A video clip would be helpful for a more accurate diagnosis. Try to get a shot of the fan turning.

 

You are going to have to spend some time under the hood while the engine is making the noise and see if you can closer locate the area of the noise. What brand of oil filter are you using and how quick does your oil light go off?

 

Thanks AK Rover and Disco Mike when my wife gets home and truck cools down I will have a look and narrow it down.
Ernie

 

It could be the secondary air control turning on. When I start mine there is a loud hum for about 15 seconds and then it turns off. It has something to do with the emissions. If you pop you hood and the noise is coming from a black box by the firewall on the passenger side then that is your noise.

 

That's my noise too. Funny, my wife asked the same question too! It sounds like there is someone in my glove box running a dust buster for a minute or so when I first fire it up.

Brian

 

Yeah its the SAI, secondary air injection, it forces fresh air down the exhaust and into the catalitic convertors to help them heat up faster, cold cats dont reduce emissons but hot cats do, so thats it what it is doing and that is why it only happens when cold.
Think of it as a black smiths bellows, he needs a hotter flame he uses the bellows to make the fire hotter, the SAI does the same thing.
That is also why you have the fast idle, a cold engine is very ineffcient.

 

Dude, "High-Five". That was probably the best answer I've ever heard... about anything. Nice. Now I have something to tell my wife.

Brian

 

Thank you, thank you...I'll be here all week and dont foget to tip your waitress.

 

My SAI pump started howling a few days ago louder than normal and I removed it, opened it and inspected the filter and it is falling apart with the touch of a finger. A few pieces where INSIDE and I had to blow air through it to get the chunks of filter out. It no longer howls but I don't have a filter in it. =(

I am gonna try and get filter material from the local hardware store and cut it to size, I am afraid dust will damage the bearings in it with out a filter.