1PZ warm engine knock - help

[swenz]

my 1PZ sounds its usual rattly self when cold. But when warmed up, cruising at around 55km/hr, there is a metallic knocking sound coming from the middle left hand side of the engine (its a RHD truck). Its irregular too, sort of sounds like a train on a track. Took it to mechanic, and he said it wasn't mechanical and not to worry (he only did a listen test). I can induce the same noise when warm and I wind up the idle when stationary. Any ideas?

Take it to a different mechanic maybe?

cheers

 

[ForealBoreal]

big end bearings? does the thing still run fine?

 

[swenz]

runs like a dream! No vibration, still pulls well. Only makes the noise when at a certain rpm. Sounds like a heat shield knocking back and forth, like tapping a set of drum sticks on a metal sheet - bizarre. I think because I can induce the sound when stationary and increasing the revs to a certain point, that it must be mechanical.

 

[crushers]

2 piece flywheel springs ... pull the clutch and take a look. it shouldn't grenade anytime soon but it is a nasty sound.

 

[swenz]

hi Wayne
been there done that. My 2 piece exploded last year. and you're right about the sound!. Now have single mass flywheel. So its not that.

cheers

 

[crushers]

did the sounds start shortly after the single mass was installed?
could it be the springs in the clutch disc then?
could it be the 2 piece pully on the front?

 

[john_d]

I experienced a similar problem with the radiator fan.

 

[Radd Cruisers]

Valve set probably needs to be done. Can sound pretty bad at certain RPM ranges.

Sometimes the injection pump will make noise as well.

~John