Do the chains have to come off to replace the VVT? What all is involved? Anyone done this have a quick replace method??

 

The same process as getting to the Chains and Tensioners...
What makes you think the VVT unit is bad, and which Bank...A or B

Regards,
Charles Pace

 

Yeah, I have the same question. And no, there is no "quick method". There is no keyway between the cam and the VVT.

 

From personal experience - if you are getting error codes from one or both of the VVT solenoids, try cleaning the terminals before you go to the expense of replacing the solenoids. I bought a can of Radio Shack spray electronics cleaner and the check engine codes I was getting (from both banks, the left more than the right) haven't returned in almost a year. Mine had a layer of oil residue in them that was causing an intermittent interruption in the flow of current to the solenoids.

 

well i have one that is clicking until i rev up to about 1500 rpm then i hear the whirrr and it is all quiet. I've already pulled my stuff apart and replaced the tensioners and my chains are tight as can be so I know its the VVT on the passenger side. I haven't tried the thicker weight oil as of yet but I'm going to. Just was thinking of replacing the unit with new but others say just drive it its not hurting anything...just annoying to hear it.

 

From Jaguar's own Technical Description of the VVT operation, they state themselves that operation can be impaired with high oil temps causing low oil viscosity. A TSB was issued to this effect & later engines had a higher-capacity oil pump, together with an Engine Oil Temperature sensor.

As the main problem lies with low oil viscosity, a thicker weight of oil may help. It has also been suggested that the oilways may be partially clogged up & can be cleaned by using a Diesel engine oil in the sump instead-as these contain a stronger package of detergents to clean engines & oilways.

 

The VVT Click should be heard a few seconds after initial start --- if not the solenoid of vvt is not working and suppling oil pressure to the VVT; therefore not allowing the VVT to operate/ adjust cam /timing.

Periodic clicking of the VVT is normal.

All vehicles with metal timing chains will also have a slight tick/click on start up ---- If it still a steady click after 2 to 3 minutes then start worrying about tensioners or streched/misadjusted chain guides.

Tha is why most vehicles today use "timing belts" that have to be changed every 60K miles instead of timing chains.

Regards
Charles

 

Sorry-- I forgot to mention...If the VVT is not getting sufficient oil..to activiate it. Your vehicle will get a CEL light shortly after you put in Drive and start to accelerate....the code will be something like 1395 or 1396.

Regards,
Charles

 

I don't get codes from it just annoying to hear it! Until I rev the engine to 1500 rpm it will click and tap.

 

Add a can of 'Restore' to your current oil. If that fixes it, and it should, move up in oil weight next change.

 

I have some suggestions you may want to try to isolate the noise, since you are not getting a CEL or code associated with the VVT yet you are getting noise from one of them and have replaced tensioners and chains.

VVT unit is bascially in neutral doing nothing when XJ8 is started with no load.

Do you always have to Rev the engine to about 1500 RPM for the clicking and rattling to disappear or how long does it have to idle before the noise disappears ?
Reving the engine to get the noise to stop is more similiar to issues associated with the tensioners not getting sufficient oil pressure to tighten the chains.


For Chain/ Tensioners
You may want to try lifting the bonnet prior to start-up. Have a large handle screwdriver or stethoscope handy to listen to the front of each Cylinder bank near the tensioners... so that immediately after you start the vehicle, and without revving it; You can place the blade of the screwdriver on the Valve/Cylinder Banks near the tensioner and your ear against the handle against to exclude tensioners, valve lifters etc.

Again lift the bonnet have a large handle screwdriver or stethoscope handy to listen to the VVT unit.. so that immediately after you start the vehicle, and without revving it. Note:The VVT unit activiates about 10 to 20 seconds after the engine is started...with one audible click of the solenoid. Place the blade of the screwdriver on the body of the VVT unit and your ear against the handle. 10 to 20 seconds after start up you should hear and feel ONE very distinct click from the solenoid. The clicks should not be very frequent.... until you start accelerating and driving, IE the VVT adjusting engine for timing.

Initial click of VVT solenoid is expected on startup after some seconds but not right away... if you hear constant clicking it is not the VVT solenoid but could be mechanical damage of the VVT----but you would have a CEL and get a code

The Whirling sound is not normal from a VVT unit since at start up it does not even activate for some seconds later.

Can you provide any other symptoms!

Regards,
Charles

 

well from what I read on here from others its normal to get the whirr and a click and then silence as it activates as the unit is tricked into thinking the car is moving since the engine is at 1500 rpm...Right now I can't test anything else as I'm changing my O2 sensor out on the driverside upstream...the only code I have been getting and finally it went out because it burns gas badly and runs like shiiiiit...LOL Hopefully I'll get that changed out tomorrow and see.