I've just removed the rocker covers on my 98 4L XK8 and found the ratchet has failed on the right bank secondary tensioner and it's the latest type as fitted to post 2002 XK8's, I would treat this noise as the old 'death rattle' and change it post haste. I feel we are going to experience more of these. (The death rattle was much the same as described for the old tensioners, except when you rev up, there is a zip fastener closing sound followed by quiet.)

 

I started hearing this noise back at 70k miles. Now at 116k miles. In my XK8 the VVT noise is very loud and doesn't go away on its own. I need to run the car a few minutes to allow the oil to reach the VVT. Once its warm, I have to hit the gas to about 3k RPM and it makes a rattle sound and goes away. I definitely have it worse off then most people here with my VVT but then again, the previous owners did not treat this motor well. When I did the secondary tensioners i noticed that red burned oil covered the cams, valves, ect which means oil change was never done on time or the motor has been overheated. Either way this AJ is coming out in replace for an LS by next summer.

 

I don't believe the tensioner issue applies to the 4.2L engine.

 

Of course, the 4.2 uses the tried and true duplex chains. My bad.

 

Ladies and Gents,
First, apologies for the delay, in reporting back. The following got in the way:
1) Sorting out the issues on what makes a difference and what does not.
2) Tree branch fell on car, took out windshield and made small dent at edge of roof where the paint-less dent guy will need to attempt to pull on the paint with glue-on device - car has been repainted so this is dicey.
3) Sorting out permanent solution for lower driver door hinge metal fatigue.
4) Drop in prices for used Ferrari Modenas and F-types.
5) What we found re Oil and Filter:
a) Started having problem with 5W-30W Castrol and Mann brand oil filter.
b) Continued and got worse with additive.
c) Changed to Mann oil filter and 5W-30W synthetic, went back to same experience as with 5W-30W Castrol, perhaps a little better.
d) Changed to OEM oil filter and 0W-40W.
1. Definite reduction in duration of rattle.
2. Very small increase in valve train noise until oil temp comes up.
3. This does seem to make more of a difference after warming the car up well and doing some aggressive acceleration - "officer this was just maintenance, see, here is the email from the web-site". The idea was to exercise or exorcise the VVT actuators with new weight of oil, etc.
3. Recommended 0W-40W Mobil Synthetic and OEM filter going forward.
4. Does not solve the problem, substantially reduces symptoms.
5. I suspect the oil rather than the filter but there is little difference in price on filter.
6) What we found with ambient temperature:
a) Cold ambient temp affected duration of rattle.
b) Less of an impact then change of oil type.
7) What we found re parking angle:
a) Slight nose up ( 2" to 3" front tires to back tires) seems to work best.
b) Level is better than nose down.
c) Nose up or nose down as afforded by ramps for oil change (6" high) made matters worse under equal temperature and oil conditions.
8) Long talk with dealer parts guy who has offered a great deal of good advice including the concept of used low mileage engine:
a) This is a 2003, the VIN number is not necessarily the whole story as to whether the car has new style timing chain and tensioner parts and all final upgrades where it may be a good idea to take a look at the tensioners.
b) There are no animals to be purchased in the "complete engine gasket set" to allow a good low cost overhaul.
c) This and other research indicates about $500 each to replace the VVT actuators which require all chains and tensioners to be removed.
d) Price to change timing chains from local jag mechanic, about $2,500, that includes chains, tensioners, etc. Max price about $3,500, reduced to the extent existing parts are re-usable.

Question of the hour: This car has 123,000 miles on it, does anyone know the recommended service interval (other than never) for new style timing chains and tensioners, VVT actuators, etc.?
If these items are a 150,000 mile service item (often 75,000 miles on other double roller chain cars), it may make sense to go in with attitude of complete replacement rather than evaluation of what is re-usable. Particularly if labor gets to my caliber of performance since i don't have to evaluate "is this tensioner still good?".

Thanks to All!
Steven

 

I did make videos of different start up sounds as we progressed.
I can post if there is interest (need to figure out how).

Regards,
Steven

 

I read with much interest all the previous posts, about 18 months ago I suffered a secondary tensioner failure at 157k, there was no prior warning, I had no noise issues,luckily I was parked at the time, but 75mls from home and with my wife who's birthday we were celebrating. I first replaced the upper chains and tensioners to see if engine was damaged, luckily not then my local Indi who's an ex jag mechanic suggested a complete replacement of all chains, guides, tensioners and gaskets,also a vvt that was damaged during the failure. Total cost just under 3k. Found lower guides cracked and worn so his recommendation was validated.
So point being if I ever hear noise like yours I will vigorously investigate issue,as you are to avoid a very costly repair. Good luck.

 

Not positive this applies here, but what is your parking sequence?

What if you position your car into a parking space, put it in Neutral, secure the parking brake HARD, release the foot brake, THEN put it in Park?

The idea is to put all the load into the (cheap) parking parts, and leave no load on the (expensive) engine/trans.

The (remote) possibility is that somehow when parking, the weight of the car puts a load on the engine, which transfers to the chains, and pushes the oil out of the tensioners. Used to be a thing on the old E30 M3 with manual gearbox and a chain drive. Just a thought. I suppose it is $0 to test...

Best of luck, keep us posted.

 

Apologies to all for the delay in follow up, there have been a number of gee whiz moments along the way, happy to report the car is running beautifully.
The problem was definitely the driver side VVT.
The problem was less severe with the Mobil One 0W-40W Synthetic oil.
The Forum help in diagnosis as was vital as a link with video showing the effect of a faulty VVT actuator on a 4.0L model had exactly the same noise. (I will track them down and thank separately) in this post, the fault was demonstrated by putting a switch in the circuit leading to the VVT actuator to shut the actuator on and off to mimic an actuator fault. The rattle when the actuator was switched off was exactly the same noise we had on start up.

I looked at the cost of tools and time, including the concept that I usually buy tools and fix it myself, justifying the cost of the tools, i looked at the only reason to use the tools again was if i blew it making the repair and had to do it over. I took it to a very good independent mechanic and asked that they change the VVT and go through the timing chains, tensioners, replacing all seals, gaskets and other incidental items.

The mechanic - Original Jaguar, Covina, CA has done a number of repairs for me where cost of tools or time was beyond my capacity. They give mechanical service i find to be superior to the local dealer, especially for these cars. No free rental car but the car is repaired correctly.

There price was about $2,800 but there were a few items we found that needed replacement, that kicked it to around $3,000. That is where it really paid to have experienced mechanic on this one. I shopped the VVT's, gaskets, cam stabilzing blocks, etc. and came up to about $2,400 because i figured I would not be able to really tell what was in great shape and what could be kept as far as tensioners, chains, etc. and figured i was not going to accomplish the labor in $400 of my time.

The mechanic noticed that two of the bolts holding the VVT to the cam didn't feel right and under analysis showed stress cracking. Had i done this i doubt that I would have noticed the "feel" or been able to tell which was the right "feel" and probably would have had failure a while later, needing the tools again.

The delay was somewhat due to Original Jaguar wanting to witness the problem, even though i was asking them to proceed on my diagnosis.
There was also a bit of tap dancing as I had body work and windshield repair going on at the same time. As luck would have it fuel injector seals decided to spring a leak shortly after (not the result of mechanic - seals were shot).

When they did get the VVT's out, driver side had obvious failure. Not wanting to re-live the experience, i sprang for the other VVT. The timing chains and tensioners were latest and greatest design and in great shape.

I would encourage the following for others with this issue:
1) Go to the Mobil one 0W, 40W, with original oil filter. Give this some time, run it a few weeks to allow the new lubricant to free up any parts that are stuck in place from other lubricant. Even with VVT failure, this was getting better for and acutally started to be intermittent.
2) Make sure your battery is in good shape, the VVT actuator is a relay, if there is not enough juice during start up (under load of starter motor) relay may not throw as forcefully where gooey oil, worn mechanism, etc. can hang it up. It sounds silly, but these cars really start screwing up when battery goes south. Spotty window position memory is a usual sign.
3) Verify with someone who is more of an expert than I am if this would hurt anything but I think I would see if disconnection of VVT actuator at the connector replicates the noise you hear on start up.
4) Decide how long you want to keep the car and if you are going to be happy dropping $3K. Mine was a close call as i had paint work, broken windshield, miscellaneous bits and pieces to the tune of $10K, well over book value (by the numbers - it was total loss) however, now the car runs better, handles better, looks better than it did when i bought it at 30K miles and it would take a new F-type to make me as happy.
5) If you jump in and are in LA area, I would try the mechanic above and also ask that they check your intake system for leaks the same way they did for Steven Hood this was a separate issue that gave me a huge jump in performance.

Cheers to all and thanks to all who helped figure this out.
-Steven Hood

 

congratulations getting everything fixed and thanks for the troubleshooting report; it will be helpful to someone in the future.

with the 0W-40 you are still within the manufacturer's recommendation chart. i recently switched to this as my hill climbing routes were thinning the 30 weights a little too much.

if you are interested, try one of the champion labs filters. they make the filters for Amsoil and Royal Purple. Very good performance, excellent anti-drainback valves. i have very little startup noise under all conditions with this filter and oil viscosity setup and pressures are at spec.