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29th March 2016, 14:02 | #1 |
Gets stuck in
Rover 75 CDTi Connoisseur SE Join Date: Jan 2010
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Temporary knocking from a diesel?
Just turned into a junction and there's a terrible low frequency knocking from the engine. Turn off, no obvious lose metal work or anything in the engine bay so fire up again and the knocking has gone!
Drive off for 100 yards and then at low revs is starts again, but only at idling speed. Turn off, start again and it's gone again. I've now driven three miles whilst looking for a garage and no repeat of the knocking. So rather than go to a garage and ask about a fault that's not currently there, anyone got any ideas? I'm currently on holiday in Weston Super Mare to make things even worse. |
29th March 2016, 14:09 | #2 |
Posted a thing or two
Rover 75 CDTi Classic saloon, MGB GT, Skoda Yeti Join Date: Aug 2008
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Crank pulley ?
Pete |
29th March 2016, 14:33 | #3 |
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29th March 2016, 14:38 | #4 |
This is my second home
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I second crank pulley.
Common failure on the Diesels. Whilst it's making a noise, pour some water over the pulley. If the noise disappears, there's your answer. |
29th March 2016, 15:00 | #5 |
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Trouble is, the noise isn't there now!
The AA man has been, very promptly, but can't find an issue. He did wonder if it's the dual mass flywheel, but thought it unlikely. Going to have to drive with it and hope. |
29th March 2016, 15:01 | #6 |
Passed Away
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Another option:- engine mount?
... |
26th January 2017, 19:23 | #7 |
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Apologies to resurrect an old thread, but I have exactly the same symptoms. Bob, did you resolve the problem and get to the bottom of the knocking sound?
I've just replaced the crank pulley, and am certain it's not the issue (knocking was there before it was replaced) |
26th January 2017, 20:07 | #8 |
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Did you check all the other pulleys for play and roughness when you replaced the crank pulley?
A worn water pump will give you a similar noise to a shot crank pulley. |
26th January 2017, 20:17 | #9 |
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not a bit of heat shield hanging down on the exhaust downpipe???
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26th January 2017, 22:16 | #10 |
I really should get out more.......
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I know this sounds odd but I have found Forte Injector cleaner can fix diesel knock. I can only presume it is over or under fuelling that causes it on some vehicles.
I have had a couple of instances recently where a vehicle sounding as rough as sounded sweet after a dose of the above product on a 1/4 of a tank of fuel and leaving it to sit for 24 hours after a short run once dosed. After 24 hours or even longer if possible take it for a decent run and then fill up with premium diesel and a 300ml shot of two stroke oil. |
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