when i got my 98 it had the god awful vvt tick that once rpms were raised it went away. I have found a solution and it seems to be working. Keep in mind i only have 1000 miles on this solution and its getting MUCH better. Ready? I changed my oil with rotella t6 5w40 full synthetic diesel oil! At 1000 miles oil is already not see through so i know its doing its job. Vvt only make noise every once and a while now. Ill keep u posted as to the outcome of this after her 3000 mile oil change : )

 

The Jaguar technical description for the operation of the VVT units indicate that their performance is quite dependent on the engine oil viscosity & temperature.

If the oil temp is too low then the VVT unit is sluggish in movement & at high temperatures VVT operation may be impaired by reduced oil viscosity.

On later models an increased capacity oil pump was fitted to all engines & an engine oil temp sensor was fitted. The VVT system is normally under closed-loop control, except when the engine oil temp is at the very low or very high extremes.

 

It's likely the high detergency of the Rotella T6 freeing up the passages and mechanism that is responsible for the improvement.

I'm on the coventional Rotella 15W40.

 

Try introducing Dexron IV or newer trans fluid in substitution of a quart of oil - trans fluid has high detergency as well and seems to get the VVT passages clear quickly with normal driving.

 

i have same issue...so we should use a 15w40 oil and maybe do the dextron IV for a few thousand miles to clear the passages....mine always makes t he tapping at cold start up and then if you slowly rev to 1500 rpm you can hear the whirr and noise dissapears...

 

anyone know if we should try 15w30 or 20w50....to get this vvt quiet? What oil weight would you guys use? it has 10-30 now

 

Im a HUGE fan of rotella t6.... It only comes in 5w40 and its in everything i own, my 2012 cts coupe, lawn mower, snow blower lol everything!! Even my last caddy a 2000 deville northstar... Approved by both shell and the engine builder northstar performance in Manitoba Canada... I love this oil. Check out - Bob is the Oil Guy for its reviews.... 20% higher than Mobil 1 and safe for all engines. Its unfortunate my powerstroke has to have 15w40 or id have t6 in it too! Imho shell offers the best oils on the market... Schaffers in close second..

 

You're running Rotella in your XJ8? Is it OK to do so? I'm currently running Castrol 5W30, per the manf's recommendations. I'm interested because I've run both Rotella and Schaeffer in my Powerstroke. Fully synthetic during the winter was awesome in the truck.

 

I run Rotella T6 syn in my XJ8, Explorer V8, CanAm Spyder V2, Winnebago (Ford V10), and 4 quads - it also happens to be JASO MA (motorcycle, wet clutch) rated. I've never had an issue related to oil in any vehicle.

 

I was about to ask about this.

 

I have used 0W20 and 5W20 with the Dexron Trans fluid that has acheived success - remember, these VVT passages are small - you want the oil flowing to them quickly at start up and at idle RPM's - thicker viscosity oil, whether regular dino oil or worse yet thick viscosity diesel oil will not get the job done... if the passages are partially clogged thicker viscosity oil will not get through those passages until fully warm or at higher pressures, such as acceleration... Just my $0.02

 

In the antique automobile world it is suggested to use the Diesel approved oil because government standards in the USA allow the diesel oils to still have many of the protective additives gone from regular automobile oils. I run these Rotella Diesel oils in my antique autos. I just use regular and NOT synthetic. Most cars get less than 2K a year so synthetic is just too expensive.

BTW, what is the difference between partial synthetic and synthetic motor oil?

 

Anyone else have comments on this?

 

I can tell a difference already so mine must not have been too bad. However after 1000 miles the oil is black already so maybe is was very dirt..