Drone on start-up when cold

[DavidEdwards]

Hi,

I've recently bought a 2005 XJ8 Sport (3.5 litre) with 53,000 miles and an almost complete main dealer service history. It runs very smoothly and is all I would expect from the car ... except for the first minute or so when started from cold. There's a droning noise in the cabin that is modulated by turning the steering wheel. Things soon settle down and there is no longer any steering related noise. I'm listening to this with the Climate and Audio systems off. I've had the drive belt checked and there's no problem there - also nothing obviously with the steering pump.

My previous car was a 2005 XJ6 (3.0 litre) with a similar mileage and I never heard this noise ... I'm of an age now when my hearing is not getting any better!

Has anyone had a similar experience, or any ideas what might be the root of the problem.

Thanks,
Dave.

[J44EAG]

Have you recently checked the power steering fluid level, David? Pumps do make a little noise occasionally when cold. Additives to quieten down slightly vocal PAS systems are available via the usual aftermarket and internet sources.

The serpentine drive belt running around all the idler pulleys and riven units can sometimes be a tad noisy on start up. Damp, cold and wet at this time of the year and if the belt itself is becoming a little worn that can be a contributory factor. even though recently replaced and with a tensioner update kit fitted, my supercharged model can chirp and squeak for a minute or so after a cold start up. Belts which have antifreeze mixture on them can also make a noise. Have a general front end check to see you do not have any coolant leaks which might cause a drip or two to end up on the belt. ie hoses, water pump (although you will have the later improved unit on your car) and around the thermostat and its manifold.

What you describe does sound belt related to my mind.

Mike

[Brakebuster]

your serpentine belt its due replacement ( if it hasn't been ) Jaguar quote something like 90k miles or even 100k miles, but in real life this is around the 60k mark, which you knocking on the door of

as Mike says, the belts get tired, and are not as efficient when older and cold weather sets in

i would firstly check if the belt has been changed, if not i would get it done along with a new idler pulley and possibly tensioner , this will make your engine much quieter and more efficient

and take away the startup noises , as the alternator pulls harder at startup as well , especially with fans and heaters going etc

BB

[J44EAG]

Here is one I successfully shreaded earlier....when it fell off the smooth idler pulley! Ribbed and eared up-stand replacement idler pulley stopped that and reduced noise....with a new belt!!

Check also for wobbly pulley bearings. having removed a belt, go to the idler pulleys and check for them falling around. Unscrew the central (usually 13mm bolt) and screw out the bolt from the mounting. The central ball race often locates in two thick washer type parts, each with an 8mm thread. each washer can be wound up and down the thread to set the support length fr the pulley bearing which controls its wobbling around. a washer at either end relative to the ends of the bearing, will support the pulley and there will be no wobble. if the two washers are towards the middle of the bearing, the pulley will be unsupported and wobble when under belt load. that does make a noise. In this shot, the finger points at the pulley bearing with the "washer with the thread" around the 8mmmounting bolt. Washer movement is rare, but it does happen.

Mike

[ptjs1]

Dave,

You've read the comments about belts. One other suggestion: x350 can be prone to pas pump noise at cold or on extremes of the rack movement. There are after-market additives but Jaguar recognised the problem and produced a small bottle of their own. I think it may even have been the subject of a service bulletin which directs you to to remove a small amount of fluid then add the contents of the additive bottle.

Just a thought..

Paul

[DavidEdwards]

Thanks for your informative replies - my next step is clear!

Regards,
Dave.

[Brakebuster]

Dave,

You've read the comments about belts. One other suggestion: x350 can be prone to pas pump noise at cold or on extremes of the rack movement. There are after-market additives but Jaguar recognised the problem and produced a small bottle of their own. I think it may even have been the subject of a service bulletin which directs you to to remove a small amount of fluid then add the contents of teh additive bottle.

Just a thought..

Paul

the X308 and the X-type were also prone to PAS pump noise , but usually coincided with heavy steering for a minute after first starting the car

but all suggestions are valid until you find the issue

hope its an easy fix either way

BB

[robv12]

I'm also going to go the pas route , add the Jaguar approved additive, and see how you get on, this has cured any noisy pas I have has on my 350's over the years, a cheap tray out before you go deeper

[J44EAG]

Agree fully with Rob and others on the additive as a first try if nothing else is obvious..

i think the additive is also the same for gearboxes which can whine. I recall having some put in my V8 S-type which used to whine a bit when hot. Cured that ok.

Mike