What is the recomended oil for my BX??

wonderd · Post by **wonderd** » 23 Mar 2005, 14:59

it's a 1.6L engine and i would like to replace the oil with a fully sinthetic oil, can someone recomend a good kind like maybe the 5w40HD oil?
Elad.

citroenzx · Post by **citroenzx** » 23 Mar 2005, 19:27

Yeh, 5w40 for a performance car. 15w40 for general use.

FDV · Post by **FDV** » 23 Mar 2005, 23:48

I wouldn't, it would be too thin. If the car is low milage then use the original spec 10w/40 semi syn, if its a bit higher try 15w/40 semi syn, slightly thicker which would probably help an older more worn engine.
I did use 10w/60 fully synthetic in the 16valve for a while however. Mainly because some of the stem seals were perishing and it started to smoke, and for the fact I was taking it down the strip fairly often and required better heat control. Once the rebuilt engine goes in however, it'll be back to 10w40.
Check out www.bx16v.com in the forums as there is a section devoted to oil reccomendations, or try the 205GTi forums to see what the 1.6GTi owners weapon of choice is?
Rich

alan s · Post by **alan s** » 24 Mar 2005, 01:26

Being in Israel, I'd imagine your weather would be similar to ours; bloody hot!!
In the sub tropics/tropics the need for the thinner low end isn't as great as in cooler climates.
On the 16V I still use a thin oil mainly due to the design of the engine, it doesn't burn oil and it's low mileage. On the 8 valves, I usually run 15W40 semi synthetic. The thing is though, if you have been running something like a 15/40 or 20W/50 you will most likely find if you drop back to a 5W low end rated oil you'll possibly start burning oil.
Alan S

wonderd · Post by **wonderd** » 24 Mar 2005, 23:33

Yes Alan, the weather here in the summer is very hot but i wasn't refering to the normal 5w40 i was refering to the HD one - that is Heavy Duty oil which is (as i now learned) not as thin as the normal 5w40 and it might also clean up the engine for me.

FDV · Post by **FDV** » 24 Mar 2005, 23:54

"5w40" refers to the thickness of the oil in cold and hot conditions? Seriously, it'll be too thin! It will shake, rattle and roll! (well all BX's roll, but you get my drift!)

wonderd · Post by **wonderd** » 25 Mar 2005, 00:05

i used the old 20/50 until recently, then i changed it to 15w40 and the engine got very loud now, why is that?
should i go back to the 20/50?
I thought that if i use that thiner oil, it will clean the engine a little on the inside of it and then i would go back to the 15w40??

FDV · Post by **FDV** » 25 Mar 2005, 00:11

20/50?? Thats very thick! It might have clogged oil channels or something. How many miles has it done? If its not mega high I'd draining and refilling with a cheap 10w40, then 1000miles later the same again with a decent 10w40. Engine should be happy on that.

wonderd · Post by **wonderd** » 25 Mar 2005, 00:56

I have 295K km on the clock, now there is 15w/40 in the engine - the problem is it's just too noisy and i am trying to find a solution to that.

bikeboyz · Post by **bikeboyz** » 25 Mar 2005, 00:58

According to Castrol, the spec from 1998 for oil was :
Engine oil quality recommendations, models to1998: petrol engines, A2/A3/G4/G5/SG/SH; diesel engines, B2/B3/PD2/CD/CE
Engine oil quality recommendations, models from 1998 (1999 model year): petrol engines, A3/SJ (semi synthetic); diesel engines, B3/CF (semi synthetic)
Engine (P) GTX MODERN 10W-40 4.5/5
Manual gearbox EPX 75W-80 1.8
Auto gearbox TQ-D 2.5 (a)
Differential(s) From Gearbox -
Coolant ANTIFREEZE 6.5
Wheel Bearings LM GREASE -

alan s · Post by **alan s** » 25 Mar 2005, 01:35

Elad,
If you've run 20W50 for any length of time I think the thinnest you'll get away with is 15W40.
Are you sure the noise is from the engine and not the hydraulic pump? They can get quite clattery on a BX. At that mileage, I wouldn't be brave enough to go for a 5W oil for several reasons not the least of which is that if it does clean the carbon out of the piston ring grooves and off the cylinder ridge, you may find tyourself suddenly burning swags of oil.
Alan S

wonderd · Post by **wonderd** » 25 Mar 2005, 01:52

Yes, i am sure it's coming from the engine head, i thought at the begining that i need to adjust the valves but i was told that noisy valves are not worth opening the head and timing for.
So, you are saying i better leave the carbon where it is at that high mileage?
I probobly should get a good quality 15w/40 oil instead of the cheap one i have in the engine now?

alan s · Post by **alan s** » 25 Mar 2005, 02:40

Yep, cheap oils usually perform like cheap oils.
In my 16V I used Elf fully synthtic last time which was their top of the range oil and that car only has a low mileage. You'd have to see the difference to believe it. I only ever once used a cheaper (but good quality) mineral oil in it and the difference was just as noticeable.
Elf make a semi synth about the right grade 15W/40 which isn't all that expensive here. If you can get that over your way, that may be your best option.
Alan S

FrenchLeave · Post by **FrenchLeave** » 25 Mar 2005, 19:22

I hesitate to stick my oar in, in such exalted company; but at the risk of getting my head bitten off here goes.
There seems to be some confusion concerning oil viscosity; all oils become less viscous with increasing temperatures, this is shown as a line sloping downwards left to right when plotting viscosity (y axis) against oil temperature (x axis). The so called multigrade oils (5W/30, 15W/40 et al) also get thinner but at a much reduced rate so the graph line is flatter. The 5W or 15W means that it is equivalent to an SAE5 or SAE15 oil at low temperatures (I think it was -20C but don't quote me.). The higher number refers to the equivalence to a straight SAE oil at normal operating temperature (I think 90C but once again DQM). A 5W/40 oil therefore works as an SAE40 oil at normal operating temperatures, but as an SAE5 oil on starting. I repeat, it is still thicker (more viscous) when cold than it is when hot. The whole object of the exercise is to reduce the load on the starter motor and improve the flow through the galleries when the engine is cold. So go ahead and use 5W/40, it can't do any harm as it will give good flow when cold and normal SAE40 flow when hot. As for cleaning out gum and sludge, that is the job of the detergent additives in the oil, not the viscosity rating.
Be lucky.

czenda · Post by **czenda** » 25 Mar 2005, 22:40

If I may:
As far as I know, recommended oil for 1.6 petrol BX is Castrol GTX, which is mineral 15W40 SG grade oil. SG code has nothing to do with viscosity, it refers to detergents present in the oil.
Considering this, I buy local-brand 15W40 SJ or SL, which is cheaper than Castrol GTX.
I bought the car badly neglected, history of engine oil changes unknown. The high-detergent SJ did not cause any problems. Engine is not exceedingly noisy and I also do not lose oil.
Which, I believe, justifies my recommendation of sticking to 15W40 and spoiling the engine with higher grade of detergent instead of experimenting with viscosity.