been using Castrol EDGE 5w-30 since 2011 when tiring to find what was used before i contacted all the seat garages that serviced it 6 times and there was 2 and that was not much help but the only idea i got off the guys who service talking to them was that grade so stuck with that but i did use a engine flush first but not done it since as its not a good idea to flush engine allot as you just let the oil build protection, only reason i wanted to know is as dropping too a thinner oil from say the 5-40 it can cause more harm due too burning more oil as the engine was run on that from say new, so if your not burning oil allot and the PD engine can as its natural with that engine but i don't burn that much between service as allot say, also Quantum oil seat sell is Castrol oil, and i change the oil and filter every 12 months but I've i have said that before
This a good site https://www.opieoils.co.uk/ i think there still on here
I think I came across one of your posts from years ago while I was looking.
I'm probably going to go for the Castrol 5w-30 and replace it once a year regardless of how little I drive the car. The Mobil 1 seems to have been OK, but I've been getting my running issues since I put it in, so I'd prefer to go with something I know other people use and is fine.
I'll probably be pulling off my rocker cover in the coming month which will give me a chance to look at the cam, but I haven't had anything happen that would make me think it's on its way out.
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