Timing Chain Tensioners

[KevNoble]

I am about to change my chain tensioners, thermostat and water pump. Having read various bits on the above subject, many articles just mention the upper (secondary) tensioners. Is it also worth changing the lower (primary) tensioners, guides et al? This looks somewhat more involved, particularly removing the crankshaft damper etc to get the timing chain cover off. (I've done this before on several other types of car). If this is the case, is it also worth changing the chains, cover seals and crankshaft seal?

Thanks in advance.

[joejag308]

Kev you know a lot more than i do re these matters......
I would have thought that while you had it stripped down you would have replaced all you see......if its there in front of you and has got mileage on it...........replace it..........its for you in the long run.
We do have a lot of knowledgeable guys within the forum too,they are very knowledgeable in their own fields i have no doubt.
But we in here as administrators and i always stress im a novice as far as technicle stuff goes and can only give you the common sense answers to these problems, we do however have the technicle expertise of Dave Marks and others who can answer all the technicle stuff you would ever need.
We keep on about Dave and the other guys like Alan Proctor for the body work and paint probs, we even have advice on car renovation to concourse standard from Tony Ridge all there for you use via the forum.
Good luck with the overahaul..........Joe

[dredr62]

I'm no expert on the topic and was led by numerous articles that have been written in Jag mags and the views of forum members. Although as you point out the consensus seems to be replacement of the upper tensioners only I decided to have the whole lot done, upper/lower tensioners, guides, chains, thermostat, water pump and VVT units. Why replace both upper and lower sets? Well, because the questions on my mind were, don't the tensioners work with and against each other? Won't the new and stronger upper tensioner only increase the stress on the older and weaker lower tensioner. Seems logical to me but for all I know as an accountant - my logic could be crap. What I can say with confidence though is I don't give the tensioner issue a second thought when I put my foot down.

[Brakebuster]

the secondary tensioners have no effect upon the primary ones, they run on different chains from different cogs,

i see your logic, but it hasnt been know so far for primary tensioners to fail, they work in a different way to the secondaries, and are actually different in design

the only real reason for changing the chains is if they have worn, this would be as a result of a tensioner slipper coming off, and the metal parts will be rubbing on each other,

chains do stretch , but that is why the tensioner is there , to take up the slack



see my post with the banned pictures , lol

BB

[daveji]

This is the way this issue was explained to me.
The recommendation is to change the UPPER tensioners and water pump as a preventative measure because the older types have been known to fail WITHOUT WARNING at highly variable,fairly modest mileages,resulting in expensive damage to an otherwise sound engine.
It is not an expensive job at a good independant and is a worthwhile "insurance policy" against a severe pain in the wallet !
The lower tensioner (as has been pointed out) is of an entirely different design and this, together with the chains are much more durable and reliable, assuming proper engine maintenance.
If the lower tensioner needs changing it gives plenty of warning,(loose chain clattering) and is usually the result of wear from considerable mileage.
It is a substantial and costly job to change the lower tensioners and chains,and it seems reasonable to me to do this only if necessary.

[johnweber]

hi everyone

having had first hand knowledge of this i thought i better post

i decided to change the upper tensioners.
After removing the covers and the upper chain and tensioners you can then see the wear in the lower guides
mine had started to brake up so i changed both upper and lower
they do wear as the chain is in constant mesh with them
my car had only covered 67000 miles.

the worst part of the job is finding the tools needed to lock the cams in place
and the cost of them make your own my advice

good luck with it if you want any help or advice email me johnweber@blueyonder.co.uk

[BrianG]

At 117,000 miles I had been thinking of getting the secondary tensioners changed for latest all-metal ones for quite a while as I was getting some nasty noises on cold starts. I had already had these changed once for 2nd generation ones at 45,000 miles under warranty and wanted peace of mind, but the quote for just doing the secondary tensioners alone from the local main dealer was a joke.

When I contacted an independent dealer they said they would not do just the secondary tensioners but recommended a complete renewal and upgrade kit consisteng of primary chains and guide/tensioners, secondary chains and tensioners, all gaskets etc, also the water pump if I wanted it. All for a fraction more than the basic tensioner job from the main dealer.

The total change was well worth it: looking at the bits that came out, the mk2 secondary tensioners were getting "iffy" but probably OK for a bit longer, however one of the primary guides was cracked in half and the other was not much better. The whole job was completed by an engine flush, new oil and filter. The engine flush seems to have cured the odd noise from the VVT units, which was next on my "to do" list and has thus saved a further huge outlay. I now have a nice quiet engine!

Whether you are doing it yourself, or paying to have it done, I would therefore say it's false economy not to do the whole lot. Have the front off the engine so that the state of everything can be seen - don't just concentrate on the "usual suspects" at the top of the engine.

[joejag308]

All very good advice, i cant argue with any of it, anything worn if you have the engine stripped down and its all there in front of you needs doing.......do it.
Especially if you wish to keep the car for a while,its bound to be cheaper than exchanging the vehicle,as you can buy the same trouble elsewhere.
I had a low mileage on mine and still did the top end .........the cost was negligable against the doubt of what could happen.
But dont think Jaguar are alone in matters like these,other makes of the same type of car have their problems too, its like jumping out of the frying pan into the fire..........for most guys in here the depth of pocket is a main issue........dont worry your not alone we get people admitting cost is an issue.........if you value your quality of motoring that a 308 has the money will appear,even if in a couple of months.
Have words with your specialist if a deal could be done........then if at the end of it all you have the vehicle you always wanted..........Joe