406 Rattles

Got a '96 406 Exec (non turbo). Recently started getting a resonant sound /
rattle seemingly from the lower rear of the engine bay, but only when the
engine is just above 2000rpm - doesn't do it over or under that. As you can
imagine, it's a tad annoying...

Before I go crawling underneath to try and find it, any one had any similar
episodes / experiences?

Andy

 

I had a very simular problem. It turned out that the tensioner for the
auxilary belt (fan belt to us) wasn't doing it's job properly. I you look
under the engine, (you may have to take the plastic guard off the underneath
of the engine bay), you'll see the fan belt wobbling at that engine speed.
If this is the problem, that is,

Neil

 

Cheers for that, I'll have a look

Andy

 

Hi Guys

I had the same thing recently, I used to get the vibration between 2000 and
2500rpm and at 60mph on an A road it was annoying. I originally thought it
was something under the engine/car.

To my surprise it wasn't in fact the top left engine mounting supporting
bracket (Top left looking on to engine). If you pop your bonnet with the
engine running and then adjust the throttle to around 2000rpm you will hear
it clear as day, if you then push down on the top left engine mount support
it will stop.

There is a movement limiter that attaches to the main engine mount this,
connects via a bar and then bolts through a rubber bush, the bush will have
gone as there are only two connecting pieces within the small cylinder. It
costs £22.50 inc vat approx and takes about 10 to 15mins to fit.

This should do it !

 

Heatshields also.

 

Spot on... well, you put me in the right area anyway! I checked the movement
limiter and it had worked slightly loose where it bolts to the bulkhead.
Torqued it back up and it's eliminated the noise.

I can turn the radio down now!

Cheers mate

Andy

 

No Worries Andy,

If you get any other problems just post it, I'm happy to help if I can.

 

Well I spoke too soon, mine seems to be doing the same, can anyone give me
details on where to look,

Neil

 

Hi Neil

Scroll down to my previous post ! the answer is there!

 

Recent work on my 97 406 at 120,000 km shows that numerous subframe
attachment bolts and the RH engine mounts were loose enough to give rise to
noise (knocking on road bumps and on left hand corners) . The vibration at
abt 2000 rpm now gone and numerous clunks and knocks on bumps now gone. The
car now pitter pats over the bumps like it did when new - must have been the
looseness.