What year are your jags ?

 

Just change it at the scheduled time/mileage for any oil that the service info published by jag says. It'll be fine. Use synthetic if you like but if jag are happy with dino oil go for it.

 

+1. There will NEVER be a unanimous answer on the dino vs. synthetic debate. Follow what's written in the owner's manual and if given any latitude, choose what makes you happiest. The car couldn't care less.

 

lot's of oil is what keeps engines alive.

doesn't matter much if it is dino or synthetic, new or old, dirty or clean.

oil does not wear out.

it becomes contaminated, the viscosity index improvers shear, and the add pack wears out.

but not the oil itself.

 

I am a member of the BITOG forum and oils are a personal choice

I use synthetic in some of my vehicles and mineral in other my XJR6 AJ16 engine I use mineral in my new to me 05 XJ8 I am going to use synthetic

I do mess around with viscosity types as its very hot over here that's my decision to do so and never had any problems and some of my cars have high K,s on them in fact bought a Citroen C4 diesel for my nephew its my first sub 100,000 k car ever owned and its not even for me LOL

my Mercedes OM642 engined Jeep it was specified synthetic and it was using a quart every 3000 k,s have since gone to mineral and oil consumption stopped

The main thing is change it if you haven't done the mileage and its sat round for a while best to still change it
I do lots of k,s so its a common occurrence round here

I buy my oils from the distributor in 20 liter drums its a pity they all dont use the same oil I could buy a 200 be a hell of a lot cheaper LOL