X300 rattle around 1500-2000rpm

[HeWhoDaresRoy]

A nasty rattle has developed on my 4.0 AJ16 engine at 1500-2000rpm. I'm guessing this is the timing chain tensioner, but was wondering if it's still ok to drive the car as it's my main commuter vehicle?

Also, if anyone knows where to get the updated tensioner and a rough guide on how to fit, that would be great.

Thanks in advance.

Edited by HeWhoDaresRoy on Monday 23 September 12:04

[XJ Flyer]

If you've got any suspicions concerning the valve timing componentry then don't run the engine until it's been fixed.

[a8hex]

I'm not sure there is an updated tensioner for the AJ16, isn't that the problem with the V8, inline6's don't put anything like the stress on their cam drives. I've not heard of there being a generic problem on the AJ16 which would call for an update.
In terms of parts, the main Jag dealers probably still can get them. You can order parts straight from Jaguar. SNG Barrat and David Manners Group.
You can get the service/workshop manuals for X300, try either of the clubs (JEC or JDC) or eBay, or probably SNG or DMG (above).

I've never needed to do more than replace the thermostat on my AJ16, but the comment from people that have needed to work on the engines is they're quite straight forward. Much more so than the newer X308.

[Jaguar steve]

The tensioner may have got stuck due to build up of contamination in the oil - hence the rattle. There was IIRC a change of design sometime in the AJ16 production run to modify the tensioner to stop this happening.

It's an easy componet to access - get hold of a workshop manual and take it out and clean it. Once done, if not solved then check for loose or damaged exhaust silencers or catalysts, loose anciliary components or aux drive belt tensioner.

Try to trace the rattle under the bonnet. Feel and listen for the source, it's highly unlikley it's serious but could be somthing as simple as a missing nut from a heat shield or loose alternator bracket.

[HeWhoDaresRoy]

Thanks for that.

Took the old tensioner out, and it looked a bit worn, so I've bought and fitted the updated version.

Didn't get a gasket with the kit and now it's spewing oil everywhere, so will remove and refit with a gasket (even though the old one didn't have one either).

Anyway, the car won't start now...all good fun.

[HeWhoDaresRoy]

Car now starts and the rattle has gone. Hurrah!

[HeWhoDaresRoy]

Hmm....car now won't start and the AA guy said it has lost compression and will have damaged piston rings due to petrol washing the oil from the bores. Seems a little severe, but not sure what do do now. Was driving nicely when I last used it (Sunday).

Ho hum.