I just bought a 2003 Discovery last night - 100k miles, had all services done: gaskets, seals, etc. under extended warranty, took it for a long test drive and didn't hear anything unusual with engine/tranny etc. so i went thru with the deal. On the way home, made a quick stop in town and was on back roads home - and at a stop light heard a descently loud ticking/clicking noise. Not like the typical click of the cylinders, but louder and only when idling. Once you step on the gas, it goes away. My first thought was a belt that was going bad (cooling fan to be spesific since was stop and go in the city), but i lifted the hood when i got home and the noise was coming from the left side of the motor, toward the back near the firewall. Any thoughts on what it could be? Dealership said they would take care of it but i just wanted to have an idea of whats wrong.

Thanks for your help!

 

Sounds like the SAI (secondary air injection) pump, the filter becomes clogged and it can be very noisy at start up but there is piping to the system that can become loose/broken and rattle.

 

SAI is only active during cold starts.

 

Spike, if it was the SAI pump wouldn't you hear it even when the truck was cold instead of only once it is warm?
Alex, you have the 03 tick, do a search for tick on the forum and you will find tons of threads about it. Some guys have pulled their engines apart and cannot find it, and there was a very convincing thread that linked to a post showing how the sleeves get very loose once warm and how that may be the cause. I'm glad you started this thread, I have been busy but I was meaning to post a clip of my tick to see if anyone had any ideas, it sounds exactly the same as you are describing. Not trying to hijack your thread, just help clarify, does this sound familiar?

YouTube - ‪IMG 1111‬‏

 

It would be cool to compile all of the tick threads and get to a consensus on this common issue, if there is one.

 

As an 03, you don't want to wait around to compare noises. I would go check your oil pressure ASAP before you trash that engine.
Test it stone cold at idle and 2000 RPM's and again when warm at idle and 2000 RPM's then get back to us with your 4 sets of numbers.

 

The tick in the video is exactly what im hearing..its only when completely warmed up and idling. Took it back last night so will have an exact answer on what was up when i get it back

 

Looking forward to hearing what they have to say.

 

When you say dealer, do you mean Land Rover dealer or used car lot dealer? Thanks. I'm highly interested in the findings.

 

Can you post a clip of the sound? More than likely the common tick some of these have. You also might want to change the oil yourself to be sure what is in there (a lazy dealer will just throw in 10w30 or whatever is in the bulk bucket) if they even bothered to change it. My tick has been there since I got it and many I test drove had the same. Mine seems a bit louder right now because I decided to throw some dino Rotella in because it was on sale dirt cheap and I figured give it a try (I've been testing different types every 1500 miles or so). It is noticably louder than the M1 10W40 High Mileage I have been using previously.