CHRIS HILL · Aug 23, 2023

Hello. Im servicing my disco shortly. Is there any advantage to using 5 40 fully synthetic engine oil? I can get 10 litres for free. In the past i have used 10 40 synthetic semi syntetic and mineral oi. . Ive also used super universal tractor oil. Its allways depended on whats avaiable. Has any body got any recomendations for oil?. Does it make that much differance? Cheers

AllanWorms · Aug 23, 2023

Are we talking about a V8? or Diseasel?

Either way: 5w-40 will flow better when cold and be about the same when at 100C. Any driving you do below 100C oil temp, the 5W will give microscopically better economy than a 10W. Side-note: On my Mrs old BMW that was used for multiple short trips on the school run, I could measure the difference in economy between 5W-40 and 0W-40. 0W-40 is probably a bit expensive to run an an old Landy though.

I have a V8, I use 5W-40 Penrite synthetic, it's a full zinc oil, which should help with cam wear problems. (or at least make me feel better about it!)

If yours is a V8, whatever oil I used, I'd make sure of the zinc content or that is says it "for flat tappet engines" or similar. I don't know the the diesels need that.

CHRIS HILL · Aug 23, 2023

Thanks. Mines a 300 tdi. Cheesrs

discool · Aug 23, 2023

CHRIS HILL said:
Hello. Im servicing my disco shortly. Is there any advantage to using 5 40 fully synthetic engine oil? I can get 10 litres for free. In the past i have used 10 40 synthetic semi syntetic and mineral oi. . Ive also used super universal tractor oil. Its allways depended on whats avaiable. Has any body got any recomendations for oil?. Does it make that much differance? Cheers

Okay two questions and my answer to both NO in the 26 years with my petrol D1 and as long as it meets the spec.
I did try Mobil 0w30 once for a week and in that time oil started leaking from both rocker covers seal so went straight back to 10w40 and stayed, although now semi- synthetic, it appears to stay cleaner longer, purchased from and branded by Halfords, which was produced by Mobil and now by Comma.

In my RR days the engine oil was aways standard 20w50 the brand I haven't a clue as LR dealer serviced it, but they replaced the cam plus whatever at 100k miles.

I’m not that interested now in brands but in the old days it was it was either Castrol or Duckhams

kermit_rr · Aug 23, 2023

AllanWorms said:
Are we talking about a V8? or Diseasel?

Either way: 5w-40 will flow better when cold and be about the same when at 100C. Any driving you do below 100C oil temp, the 5W will give microscopically better economy than a 10W. Side-note: On my Mrs old BMW that was used for multiple short trips on the school run, I could measure the difference in economy between 5W-40 and 0W-40. 0W-40 is probably a bit expensive to run an an old Landy though.

I have a V8, I use 5W-40 Penrite synthetic, it's a full zinc oil, which should help with cam wear problems. (or at least make me feel better about it!)

If yours is a V8, whatever oil I used, I'd make sure of the zinc content or that is says it "for flat tappet engines" or similar. I don't know the the diesels need that.

5w40 is a bit thin for the rv8

Henry_b · Aug 23, 2023

The RV8 will take any oil you stick in it, specialists all have different opinions I've run almost every grade in mine you can think of,

and by far the best oil I ran in my Rover V8 was 15w40 castrol GTX.

The 10w in 10w40 is measured in a vein filled with oil and it is the measure of the oils resistance to rotation/spinning through that they can deduce which oil can flow better at colder temps..
the 40 in 10w40 is measured in a container with a venturi in the bottom at 100c and they time how long it takes to run out, simply put.

Put what you want in it, the biggest killer of Rover v8's isn't the wrong oil its the lack of oil or complete absence of oil changes

lynall · Aug 23, 2023

300 on full syn may use more oil than diesel
If you go this route, check it often!

AllanWorms · Aug 24, 2023

kermit_rr said:
5w40 is a bit thin for the rv8

40 should be plenty, as long as it's not all ****ing out the sides of knackered bearings

You need enough flow into the bearings to replace what comes out. They don't need pressure in them.

CHRIS HILL

Active Member

AllanWorms

Well-Known Member

CHRIS HILL

Active Member

discool

Well-Known Member

kermit_rr

Very

Henry_b

Think outside, no box required.

lynall

Well-Known Member

AllanWorms

Well-Known Member

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