Hi everyone, I am new to this site because I am a first-time owner of a used jaguar. My car is a 2005 XK eight. I'm a little distressed if not just pissed off but maybe you all can help me clarify. I just bought the car home yesterday upon starting up this morning a loud rattle for just a couple seconds and then car ran fine. Searching this form I found that it's a Vvt which deals with the tensionisor Now I own a late model Mercedes that has tensionisor so I am familiar of how they work and why they're there. First of all let me say I'm upset with the dealer personnel that I bought the car from. Car Was advertised as excellent mechanical running order. As you and I both know this is not the situation is not normal and excellent mechanical order. We also both know that all it takes is a few seconds for start up The symptoms goes away. When I inspected the car I drove 350 miles , Tampa , fl where I saw the car did not purchase it until I see a cold start the next day, then told him I want to see it first thing in the morning and I want to see the completely coldstart. We did that and obviously I didn't hear the situation. Why I'm assuming he let it run couple minutes before I got there and never heard this situation rattle. To me that's out right fraud. Anyone with a little knowledge of tensionisor knows that these do not go out overnight. My question is how serious is this? I've read that it could be just simply a change of the oil which looks like it was done recently and proper or different filter? Not sure what I want to do at this point. I know I bought the car as is without a warranty but there must be something in terms of false advertisement. So guys how serious is this I don't mind putting in a few dollars into it but I don't want to have something very costly. I bought the car as stated in advertisement as excellent working order? So everyone give me a hand at what can I expect in terms of trying to fix this problem? Thanks so much, Rick

 

The tensioner issue that is well documented in the faq sticky isn't related to VVT as it affects both XKR's which don't have VVT as well as XK8's which do. Furthermore the plastic tensioners were replaced by the 2003 model year although that is obviously not a guarantee that there isn't a problem with them. If you have the skills they aren't that expensive to change if that is the issue.

I think you must first determine if your issue is tensioners.

 

My car made that noise and only at cold start up. A short time later the idler on the serpentine belt tensioner disintegrated in the middle of nowhere. The bearing in was on the way out and that rattle was the warning sign.
Take the belt lose and see if the 2 plastic belt idlers have play or turn stiff.


Dave

 

Thanks for the information. How do I determine it's the tensionisor ? I do not get a low oil pressure code which I would think would be the result of not enough oil pressure to the tensionisor so I think The oil pump is eliminated?

 

Great information on that serpentine belt tension. So that pulley should be stiff is proper, if it spins free that means its shot and not working? Or the other way around, if it spins the bearings are good? So is it the bearings in the belt tensionisor?

 

If it has any resistance to being turned or if there is any play in them then they are shot. Eventually the bearings seize and the plastic pulleys simply fly apart. You can replace them with metal idlers and they are less than $20 each. The rattle sound comes from the belt tensioner bouncing as it tries to overcome the sticky bearing. If one is bad replace them both.

Hopefully thats all it is as its an easy fix.

Here is my post on them, 2nd post down...



Dave

 

Thanks Dave, I have a real good Indy here at my home I'll take it to him. I don't have much of a garage facility work on this myself. Hopefully this does it.

 

Tensioner issues causing slack in the cam chains is often described as a 'rattle'. VVT noise is more often described as a 'ticking' on cold start. If the noise only happens on a true overnight cold start that might imply VVT issues although even at the first of October I find a 'cold' start description somewhat misleading for a Panama City Beach, FL location.

You do not identify the miles on the car. VVT issues tend to be wear related, tensioners can fail at any time.

There have been several reports of failed tensioners of the later metal version. They have a ratcheting action that is intended to prevent retraction and slack even without oil pressure. If you are sticking with your 'rattle' description that means it should be imperative that you get the valve covers off ASAP . . . as in TODAY.

A quick, cheap test for VVT vs tensioners is to add a can of RESTORE oil treatment. It thickens the oil as would changing it to a higher weight oil would. If that quietens the noise perhaps it is the VVT's and that oil change is all that is needed.

The oil pressure 'gauge' is really an idiot gauge that is off or on based on an oil pressure point of 7psi. Not much comfort for a $12,000 engine. Search 'RealGauge' for a solution to that issue.

 

Ok, I'll do that first. In my bio I did put mileage of car but perhaps it does not show in posted threads. The car just turned 69k

 

If the problem is the belt tensioner, it is often more of a 'knock' on startup rather than a rattle. If you have someone else start the car when cold, and observe the belt tensioner with a flashlight, you should see it 'bouncing to the beat'.

 

Good news I think? Added the STP oil treatment. Coldstart this morning in Panama City Beach, it got fairly low last night chili. I couldn't even count to one and the rattle dissipated. Is there any reason of concern for the slight rattle at start up?

 

My only concern would be your description of the noise as a 'rattle' vs 'ticking' as mentioned earlier. 'Rattle' has been universally used to describe chain looseness associated with tensioners and it would take less than a second for the chain to jump the sprocket teeth.

 

4.2 engines have very few issues. If you believe the condition to be "internal", I would start with a fresh oil change, using a recommended filter, and the correct viscosity oil. Who knows what is in there now?

 

Something else I forgot to mention . . . cheap oil filters sometimes do not have back flow valves allowing oil to drain back into the slump when sitting idle. That requires the oil pump to fill the drained filter before lubricating the rest of the engine. That often shows up as a few seconds of delay before the oil idiot gauge comes off its rest . . . and perhaps a little engine rattle on cold start-up.

A fresh oil change with known correct oil and verification that the new filter has such a valve would seem cheap insurance.

 

For over a year my 2005 4.2 has given a quick (half second) rattle on first start of the day. The symptom matches descriptions of VVT noise. Perhaps some day I'll replace the one that's rattling, but unless the noise changes or becomes more frequent, I can live with it.

 

REDXK8,
I have an 05/XK8CF, so if you would like to chat, give me a shot. I live in Panama City. I may be able to help with some of your anxieties............

Cheers
Chuck

 

Quick question, what is a good brand for low drive up ramps for the XK eight? I have low profile ramps for Corvette but the Jaguar seems to be lower than my particular your Corvette. So are there any ramps that you know that are low-profile that will fit underneath this jaguar?

 

REDXK8,
Hey Red, I'll get with you sometime tomorrow--Sunday--then we can make plans to talk.

Chuck

 

Thank you, Rich