Hello Everyone,

In solving the rattling loose timing chain on my AJ16 S/C, I have come to a dilemma. What began as a tensioner blade replacement has turned into that and a head gasket and coolant hose replacement as well. Thanks to me breaking the front part of the head gasket as the timing cover was going back on. This may have been a blessing in disguise though because it's given me the opportunity to replace those two unreachable coolant hoses as well as delay the potential for oil leaks to occur from the oil passageway in the head gasket.

Even though I thoroughly enjoy emptying the contents of my engine compartment, I'd rather not have to redo this job. I am thinking of all possibilities that may cause the rattle to return, I've replaced all guides and dampers in the timing chain system but it seems as though the lower timing chain tensioner is NLA. Does anyone know if there is any source to replace/overhaul this tensioner?

The workshop manual recommends checking if the ball valve emits an audible rattle when shaken. This rattle is present, but seems to be intermittent (also I can't seem to figure out how to remove this ball valve from the housing). Next the manual recommends "renewing the ball valve assembly", but this seems to be just as NLA as the tensioner itself. I'd like to renew the o-ring at the very least, but that won't be possible if I can't extract the ball valve from the housing.

I know that was a lot of information, but any thoughts would be appreciated.

I have attached images showing a very worn damper (wondering if this was defective and the cause of the rattle), and the disassembled tensioner.

Thank you!
Michael

Old vs. New Tensioner

New Guide placed on top old guide. Weld not broken, but guide was bent

Tensioner disassembled as far as I am able

Ball valve in tensioner housing

Tensioner housing

 

Michael,
Been there, done that, down to and including breaking the head gasket extension with the timing cover!
I replaced the upper and lower tensioners, guides, chains, and it still rattles momentarily on the first start of the day! You will see extensive discussion of the issue on various threads in here, and having been in the market for a cure, I have followed these closely over the years.
The key points seem to be:
1) There sound comes from the upper chain, and a momentary delay in the tensioner taking up the slack on startup.
2) There are no recorded instances of it leading to any adverse outcomes
3) Using thicker oil (20w50) can make it go away.
For my own part, I am not keen to use a thicker oil than specified by Jaguar for my climate, as it may well compromise lubrication, and have decided to live with the momentary rattle, which seems to be the route followed by many. Replacing the various chains and tensioners is no doubt good practice, but is probably not necessary. I chickened out on replacing the head gasket, as my car goes from one years end to the next without using a drop of water. I sealed the timing cover with Hylomar and it seems to have worked.
At the back of my mind, I recollect someone had some success fitting a shim into the upper tensioner which had the effect of compressing the spring slightly more, resulting in more pressure on the chain pending the arrival of oil pressure. It struck me as an interesting idea, and I might try it some day, but in truth the rattle doesnt annoy me any more!

 

Its been YEARS since was into mine.

I also had issues with info on that ball valve, so left it be.

Those dampers etc look SAD, and scream of lousy oil, and /or oil change periods.

Pre firing that lower tensioner was critical. as it will NOT fire off like the top one when the engine starts. I did NOT pre fire it, not properly at least, so in I went again, as the rattle was LOUDER than before.

This PDF is old, like me, but maybe there is something in it to aid you.

Good luck.