Whats the Best oil for the engine?

Rgod · Post by **Rgod** » Mon Aug 10, 2009 2:03 pm

Hello

Im using 20W50 ,i heard that 15W45 is the recomded one.

BX 89-GTI B6d

MULLEY · Post by **MULLEY** » Mon Aug 10, 2009 7:48 pm

I'm using semi-synthetic 10w-40 which i believe citroen recommends. I cant see the point in going fully synthetic as price is rather a lot. I think some club members cars which have a few miles under the belt tend to use a thicker viscocity than what i use, just depends how good your engine is & mileage.

Not sure if citroen recommends a different type depending upon what engine is fitted in what country, as there might be specific reasons for having a different viscocity?

Philip Chidlow · Post by **Philip Chidlow** » Mon Aug 10, 2009 10:03 pm

Just to throw a spanner in the works, although with all my previous BX I have used 10/40 semi synthetic, my current GTi auto has always had quality synthetic oil at it's frequent changes (around 40! - for which I can only take credit for two) and now, at 214,000 miles or so it still uses very little oil and there isn't the usual blue smoke display that high mile petrols usually exhibit. (And the valve stem oil seals haven't been done and the head hasn't been off...).

Whereas some petrol BX's with less miles that I've had did.

Dunno if the oil choice is a factor. But I'd hazard a guess that if your BX hasn't always been fed with synthetic, then there'd be no point in starting now...

Way2go · Post by **Way2go** » Mon Aug 10, 2009 10:17 pm

Now I'm not an expert in oil or "liquid engineering" as Castrol put it

but I don't think you get any especial benefits of using synthetic with the BX engines. Correct me if I'm wrong!

I seem to recall that the benefit is in being to extend the oil changes to 12,000 miles as a marketing ploy on newer cars so that they could claim reduced servicing costs in normal use. If you still change the BX oil at 6,000 miles (or less) then that negates this advantage.

Philip Chidlow · Post by **Philip Chidlow** » Tue Aug 11, 2009 12:28 am

IMO what you say is right. I'm only sharing the facts about one BX - it's probably a fluke (unless there was an engine change along the line that wasn't recorded...

). Thing is, now, would I be advised to keep up the tradition and continue with fully synth or start using semi?

But as the original post is about what best to use, my advice, based upon the ownership of 11 other petrol BX's is semi, all the time. Saves a bundle if nothing else - especially as I don't seem to be able to keep a single BX for more than (at best) 35k miles before moving on!

jonathan_dyane · Post by **jonathan_dyane** » Tue Aug 11, 2009 12:34 am

I have heard tell of switching from mineral to synthetic and/or the reverse may cause seal issues, but it could be a load of bollocks.

FWIW, the smoothest and fastest (by a long way) 2cv engine I have ever experienced had been run from new on fully synthetic oil. (Until I bought it anyways; How much! No, this 15/40 diesel oil me dad buys in bulk will do just fine thankyou very much...)

TB2 · Post by **TB2** » Tue Aug 11, 2009 12:50 am

A classic topic. See these threads for past discussions

http://bxclub.co.uk/forum/viewtopic.php ... hlight=oil
http://bxclub.co.uk/forum/viewtopic.php ... hlight=oil (TD)
http://bxclub.co.uk/forum/viewtopic.php ... hlight=oil (TD)
http://bxclub.co.uk/forum/viewtopic.php ... hlight=oil

The list goes on. Conclusion revolves around brand 10W-40.

Post by **Tim Leech** » Tue Aug 11, 2009 10:47 am

Ive always used 10w40 semi synthetic in all my petrol ones and never had a problem.

kiwi · Post by **kiwi** » Tue Aug 11, 2009 9:06 pm

10w40 Semi Synthetic better quality Oil, easier on the engine when starting from cold, better lubrication at lower temperatures (Cold Engine), maintains its protective qualities longer.

Nuff said

Well nearly the price differance is not much at all in the scheme of things! Only thing that hacks me off is can never sem to get larger than a 4 ltr can where as 20/50 you can get 5 litres.

Kitch · Post by **Kitch** » Thu Aug 13, 2009 12:08 am

10w40. Synthetic or not doesn't matter in our cars unless you rarely change the oil, and at the sort of mileages our cars will now have, it'll make little difference.

Most 10w40's are semi-synthetic anyway. They practically all come from the same place! You'd be hard pushed to find fully synthetic and would probably pay too much for it.
15w40 can be used in the diesels though, and in the XU's if they're burning 10w40 a bit too quickly.

The only thing abnormal I ever put in the valver was Castrol RS 10w60. Bloody pricey, run very smoohtly on it but I often wonder if I'd have suffered oil surge if I'd have thinner oil in it. Oil pressure held up well at high temps though.

nige! · Post by **nige!** » Fri Aug 14, 2009 10:41 pm

my bx diesel engine oil is replaced every 6000 with an engine flush. Hopefuly this will keep me right for years to come