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GU Series 1 4.2 diesel - top end engine noise

4K views 6 replies 4 participants last post by  Tracteur Tom 
#1 ·
I have searched the various threads concerning tappet or rocker noise for the 4.2 non turbo diesel. My 1999 GU is a little different. I have a harsh lifter type noise above 2000rpm. Thinking it was the rockers requiring adjustment I have done that. No change. Then I removed the rocker shaft assembly to see if the rocker arms had wear on the faces. They are good. The vehicle has done 266k and has regularly been serviced.

I now suspect either the rocker shaft or lifters are the problem. Anyone else had a similar problem and found the answer?
 
#6 ·
seems silly but make sure its not the air filter housing.

Mine makes noise. Infact when using a Ryco filter it was making noise because the filter wasn't sealing properly. Quick adjustment of the lid with a bit of manipulation fixed that though.

Still don't use ryco filters however.

Also, tried changing oil brand/type? If the noise changes pitch or volume with a different type of oil it might help identify where the problem lies. And its cheaper and easier than pulling the head off or replacing the rocker assemblies (a common problem)
 
#7 ·
Yes that air filter box caused a strange tappetty / little end type of rattle on my TD42, only at a certain speed. I found that the long bolt that tightens the clamp to the inlet manifold was loose !

A 2nd opinion is always a good plan with strange engine noises. Take it to a mate or a mechanic for their advice.
 
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