DIFFLOCK66

DIFFLOCK66

Well-Known Member
When the engine's cold, I can feel a noticeable vibration at around 2000 rpm. Above and below that, the engine's smooth - it does get slightly rougher as it nears max revs - any engine's vibes will change a little.

Once it's warmed up, then the vibe goes away. I haven't taken the acoustic cover off and had a listen with a screwdriver or stethoscope whilst someone revs it yet.

How much play should the viscous fan have on its shaft? There's a little play between the centre of the fan - the metal part with the cooling webs on it - and the shaft. That may be the culprit - the viscous coupling will change its behaviour as it gets warmer.

I haven't taken the serpentine belt off to check all the other pulleys for play - there's no noticeable noise over and above the engine...yet.

Any Ideas? Could it be injector(s)?

I have changed the injector loom recently & cleaned out the red plug at that time,but not cleaned it since.
 
Hello,

Id remove the fan first then run it up and see what it does.. seems strange that it doesnt happen when the engine is warm..

W
 
I knew there was a reason for buying that viscous fan spanner ;) :D

HOWEVER, On driving home tonight I gave the vibration a little more analysis - it does vibrate through the car i.e through the floorpan and bulkhead - I can feel it in my feet. I'm wondering if it's an engine mounting which has gone or on its way out? The resonance makes the engine sound louder. Once it's warmed up properly, I'm guessing perhaps everything expands enough to move the mounting and thus insulate more?

I'm off out to check for a collapsed mount :cool: and to see if I should then unbolt the fan!
 
Well, the offiside engine mount has failed the probe test - you can see the rubber just through the hole in the bottom plate! No 10mm distance there then ;)

Whatever else, new engine mounts are required. Doesn't really explain how the vibration goes away when everything's warmed up - surely umpteen kilograms of engine wouldn't move that far..... :scratchingchin:

EDIT: Nanocom (thanks John!) didn't throw up any faults FWIW
 
Last edited:
There's a couple of holes on the underside of the engine mounts. Poke a drill bit or pencil up into the hole. If it goes in at least 10mm then the mount is fine ;)
 
Go for Genuine engine mounts, i had FOUR pattern ones fail, spent hours and hours chasing vibrations that were caused by new faulty pattern mounts
 
Update - It's not the viscous fan. Removed it today and have the same vibrations. Two new mounts on order from DLS.
 
DIFFLOCK66 said:
Well, the offiside engine mount has failed the probe test - you can see the rubber just through the hole in the bottom plate! No 10mm distance there then ;)

Whatever else, new engine mounts are required. Doesn't really explain how the vibration goes away when everything's warmed up - surely umpteen kilograms of engine wouldn't move that far..... :scratchingchin:

EDIT: Nanocom (thanks John!) didn't throw up any faults FWIW
Click to expand...

I knew me spending 300 quid on a nanocom would come in handy,for you.:pound:
 
I also have an intermittent vibration that you can feel through the accelerator pedal but mine will vibrate off and on for 3 or 4 days and then won't happen again for a few weeks.

I have convinced myself (rightly or wrongly) that it is the acoustic cover or the oil filler flap on the cover that is vibrating but I have never been able to pop the bonnet when the vibration is happening to check.
 
Thinking about things further - the vibration is there when the engine is coming back down through 2K on the overrun, no throttle. My understanding is that the injectors would be shut off - no fuel = no misfire to cause any trouble.

Perhaps the clutch or flywheel, although that was changed about 3 years back according to the paperwork i got with the Disco. Only done 167k miles total, flywheel changed I think over 100K miles so not done a lot on it relatively speaking.
 
When the wifes Renault Megane gave a loud 'CLUNK' and spat out half an engine mount, even though it was petrol and a very smooth engine, it felt like being driven over cobbled stones.

IMHO don't chase different faults till you've sussed the faulty engine mounts, you might just screw something else up .. :)
 
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