Q: Apart from the usual chugging diesel noise, the car makes two loud noises. At low revs, it gives a gruff deep sound. This reduces drastically if much higher revs are applied. On motorways, I have to press the accelerator right to the floor to avoid a horrible deep sound, instead I get a less horrible higher pitched sound. As the car accelerates, the noise gets gradually louder, it seems to be worst at 60mph, and then at higher speed it starts to reduce a bit. The pitch is quite low until 60mph and then starts to increase in pitch. If I depres the clutch a bit, the volume of the sound decreases. If I press it a bit more, you get the expected sound of a car revving when out of gear. In neutral there is only the sound of a diesel engine. The sound seems to be about the same whether accelerating or decelerating. If I change from 5th gear to 4th gear at high speed, I get the loud deep sound again. I would like to identify the problem and fix it or at least find ways to deaden the sound.
A: Hi, it is unclear if the noise is only when you are actually driving or at all times. Have have tried the following: Driving along at say 60km/h (or wherever you have the noise) in 4th gear on a straight road, no other traffic. 1) push in clutch fully, no accelerator, gear lever still in 4th. Does noise change - how? 2) clutch still in, put gear lever into neutral. Does noise change - how? 3) gear lever in neutral, let clutch out Does noise change - how? 3) WARNING - don't lock the steering on this one - turn engine off (should now be coasting in neutral with engine off) Does noise change - how? 4) clutch in, put into 4th gear with clutch still in Does noise change - how 5) turn key on, start engine, let clutch out slowly and drive off, tell us what happened.