Offroad-Express

The engine has taken to making a whistling sound (makes a sounds like old televisions did when turned off the broadcast…) – it happens only under light throttle between 1100 and about 1800rpm. Increasing or decreasing the throttle the noise instantly stops. The sound doesn’t change pitch when increasing the engine rpm’s.
Engine has to be fully warmed up for the noise to occur.
Can’t tell where the noise is coming from when listening under the bonnet as it gets lost with the other engine noise, but it’s quite noticable from in the cab.
Apart from the noise, the truck drives great.
Any ideas?

my best bet would be on either the head to exhaust gasket or the second guess would be a turbo gasket, my old truck did this and the exhasut gas passing between the steel gasket made it whistle on light throttle when warm

wastegate leaking??

mine whistles a wee bit ... i just turn up the stereo

There was a thread about a valve in the injector pump a while back may be worth a search.

There are a few things that create a whistle type noise in the 1KZ.
1 - EGR bolts/nuts come loose
2 - Turbo impellor fins get gummed up
3 - Fuel return valve in top of injector pump.

To fix:
- Check and tighten EGR bolts/nuts
- Clean impellor fins with carbclean or similar
- Replace fuel return valve with ND modified part (DSL have the part
available)

Edit: reading your post again, I think it could most likely be the fuel return valve. Very easy fix
Part number : 096020-0270

Problem sorted (was the fuelscrew) thanks to this website and it’s members! I’m really pleaeed I asked the questionheer as I would never have found the source of the problem otherwise.
With regards crap build up on the turbo compressor sometimes causing a noise, this doesn’t surprise me with the amount of crankcase vapours going through the turbo on these things.