Thread: Knocking at idle

Down the rabbit hole I have gone. 2 shops and 3^rdon the way.

I have a knocking / metallic sound only when warm and only when the vehicle is in D or R. It does not make it when the vehicle is moving, in overrun or when I apply throttle. Vehicle stops, idles for a second or two then the knocking comes back.

It sometimes does it when there is a very light load on the engine. IE if the A/C clutch is connected but it can be hit or miss.

There is also a slight vibration when going from D or R into N which lasts for about 3-5 seconds and then stops then the knocking sounds starts. It might not be related just old age.

The vehicle had a miss, and the first shop really didn’t know what it was doing. I ended up replacing the injector harness, all the injectors (x5 rebuilt), new glow plugs etc. The vehicle continued to have a miss and then developed a knocking sound around the same time. It had a miss then a knock after.

Vehicle still ran rough, and the first shop threw up his hands. Second shop identified as a break in the engine harness which was intermittent. He changed the ECU and the injectors for known good ones and when it still ran rough, he took the heads off to confirm there was no damage and to my surprise stated everything was perfect inside the engine. My ECU and rebuilt injectors were put in and the engine ran smoothly but still had a rhythmic knock at idle only. The vehicle had a knock with the known good injectors and also the rebuilt ones.

We have almost past the 10 months mark of going back and forth but we have changed:
-Engine mounts
-Tensioner and new belts
-One of the glow plugs was faulty (causing rough start in the cold)
-Tested cylinder pressures all 4 are at 440PSI
-All head components were removed and checked for condition and new seals and washers were used for the injectors (again) I think they have been removed 3 times now. New head gaskets with steel dowels etc

I like the second shop, they are a LR specialist, but it takes about 4-5 months every time it goes back in and still comes out having the same issues. Due to them fixing the first shops mistakes I feel like we are looking in the same area constantly.

The engine is running better than ever. Starts straight away with no weird vibrations and idles very smooth. Nanocom shows no issues with cylinder balances at idle. All +/- 3

Before I make the big trek to Melbourne. I have asked for a 3^rd shop (local) to just run their eyes over it to get a fresh point of view to make sure we are not missing something.


My thoughts:
-Possible TV Damper (it was looked at by the second shop and they said it was fine) they couldn’t see any play
-Cracked flex plate but it doesn’t make any noise when going through the Rev range
-TC feels ok. Locks up when it should and doesn’t shudder when fully locked and I step on the pedal.

Any experts or people with similar situations I need your advice before I go insane.

Originally Posted by Mattjones346

Hey Shack a friend if mine has sent me your way to tune my tD5 defender but I can't find any contact information for you. Do you still tune td5s?

For sure!

I've sent you P.M.