Have a 1999 S-type V8. Car went into limp home mode. Took it to the dealer for scan. They said codes for timing chain/tensioners (but couldn't give me printout...). Dealer said rattle from both cams, but couldn't identify if secondary or primary. Did notice rattle on startup a few days previously but didn't think about it. Have had car towed to home and removed both cam covers. Looks like original secondary tensioners and they appear all intact and tensioners look OK. Looking down cover to primary chains and guides, they all look ok and intact. I REALLY don't want to pull the timing cover off to get to primary chains...but of course there may be damage that I cannot see. All chains appeared to be tensioned OK, but I am only guessing it is OK. I would replace the secondary tensioners and probably chains anyway, now that I have got this far. Am I kidding myself that the primaries are OK? Should I drop the sump and look for broken plastic? Christopher's Foreign Car Parts sells a chain kit with master links. Is there any advantage to using this-presumably you would cut off (not sure how) the original chain without disturbing cam (using lock tool).
I intend to sell the car when running again, but I don't want to leave problems for the next owner. Is it reasonable just to replace the secondary chains/tensioners...but if primary not OK I would have wasted time/money?

 

There are no codes for tensioners.

I would be hesitant to even start the car based on your description and concerns as a chain may have jumped a tooth. Jumping another could be fatal to the engine. Obviously, you need to change, at least, the secondary tensioners just because of rattle and age. You need to get someone to read the codes and post back here. Perhaps we can help.

Replacing the secondary tensioners first is not a waste of money as they truly need it. A knowledgeable buyer will question and severely discount the car for having the original plastic tensioners. Most only change the tensioners, not the chains.

 

OK so if I replace the secondary tensioners and that cures the rattle, should I leave it at that? I guess the risk is that it could have an unseen broken primary tensioner, but if the rattle is cured, then perhaps I should just sell the car then. If it is not cured then...pull the motor down again.