C5 2.0i engine oil

[faddy]

The table in the maintenance guide and the Wiki gives a range of acceptable oil specs for most engines listed, but for the 2.0i 16V engine just the one, fully synthetic 5W40. Why's it so prescriptive for this particular engine and would I be ok with fully synth 0W40 (Mobil 1 at Costco price )? I presume there's nothing magic about Total branded oil?

I'm very much not a mechanic, or fond of crawling under cars, but I'm tempted to do my own oil change using a vacuum pump. I've never changed a cartridge style oil filter before, can it be done reasonably cleanly?

[GiveMeABreak]

The specifications are designed to meet the various engine types - low SAPS for diesels with particle filters for example and of course the climate of the country you are in. So the best thing to do is identify the specification for your engine and that will provide the correct grade (s) and then cross reference with climate range where you are to find the best protection.

So assuming you have the DW10ATED Diesel, 5W 40 will provide good all round protection. -30° C to +50° C. The 'W' stands for winter. The lower the *W number the thinner the fluid - so you don't really want to use 0W unless you are permanently living in the Arctic Circle A thicker more viscous oil will provide better protection - but it also needs to be able to get around the engine quickly in cold temperatures, so stick with the recommended 5W 40 for this climate I would suggest.

[Paul-R]

That's not the way I understand oil terminology Marc.

Yes, W stands for winter but what they're saying is that in winter (I forget the exact temperature that they specify is winter) that's the equivalent viscosity of the oil when cold. In other words the 0W will be thinner than the 5W in cold conditions and will put less strain on the oil pump, will flow round the engine quicker and use less power to be pumped.

The second part of the designation is the viscosity when at operating temperature. As they're 40 they will, effectively, be the same.

Unfortunately viscosity is not the be-all and end-all of oil. For modern engines with particulate filters (DPF or FAP) it's very important to have an oil that leaves behind as little solid matter (ash) when burned as this will give the longest possible life to the DPF. This is called low SAPS oil. There's also the long service periods that are now the norm but if you limit the maximum to 12,500 miles (I know a lot of people here will say that's too long) you should be OK.

As Marc says, check the listing to find the specifications to see what PSA say should be used and see if Mobil 1 supports this. Whether it's 0W40 or 5W40 shouldn't affect the spec. I think that Mobil 1 was used by the previous owner of my X7 but I can't check this at the moment.

[GiveMeABreak]

I thought that's what I just said in not so many words.

The recommended is 5W40. '0W30' is not recommended according to the manufacturers Specs. I didn't go into DPFs and low SAPS here as he doesn't have one.

[Paul-R]

... so you don't really want to use 0W unless you are permanently living in the Arctic Circle A thicker more viscous oil will provide better protection - but it also needs to be able to get around the engine quickly in cold temperatures, ...

It was this bit where I thought the logic went wrong.

You can use 0W instead of 5W as it provides an extra reserve of low temperature capability that isn't necessary most times in the UK. If it's cheaper than 5W why not? A thicker oil will provide more protection only if the surface film is in danger of breaking down but we've established that both oils are SAE40 when hot so there will be no difference then. And finally the bit about the getting round the engine in cold temperatures is correct but to me infers that the 5W will be better - a bit picky that last one I'll accept!

[EDC5]

So, the number before the W is the cold viscosity, the lower the better practically speaking. The number after the W is the hot viscosity, this can't be changed as the engine will be designed for this oil.

is that correct?

So is there any harm using 0W30 instead of 5W30 ?

[GiveMeABreak]

To quote from Total:

Engine oil viscosity refers to how easily oil pours at a specified temperature. Thin oils have a water-like consistency and pour more easily at low temperatures than heavier, thicker oils that have a more honey-like consistency. Thin is good for easier cold weather starting and reducing friction, while thick is better for maintaining film strength and oil pressure at high temperatures and loads.

and...

Viscosity is notated with the common "XW-XX." The number preceding the "W" rates the oil's flow at 0 degrees Fahrenheit (-17.8 degrees Celsius). The "W" stands for winter, not weight as many people think. The lower the number here, the less it thickens in the cold. So 5W-30 viscosity engine oil thickens less in the cold than a 10W-30, but more than a 0W-30. An engine in a colder climate, where motor oil tends to thicken because of lower temperatures, would benefit from 0W or 5W viscosity. A car in Death Valley would need a higher number to keep the oil from thinning out too much.

So we have a wide climate range in the UK and Total recommend (for my engine at least) 5W-40, 10W-40 or 5W-30. I wouls still say 0W-XX is too thin for the UK and is not on the recommended table.

[bobins]

Viscosity is notated with the common "XW-XX." The number preceding the "W" rates the oil's flow at 0 degrees Fahrenheit (-17.8 degrees Celsius). The "W" stands for winter, not weight as many people think. The lower the number here, the less it thickens in the cold. So 5W-30 viscosity engine oil thickens less in the cold than a 10W-30, but more than a 0W-30. An engine in a colder climate, where motor oil tends to thicken because of lower temperatures, would benefit from 0W or 5W viscosity. A car in Death Valley would need a higher number to keep the oil from thinning out too much.

So we have a wide climate range in the UK and Total recommend (for my engine at least) 5W-40, 10W-40 or 5W-30. I would still say 0W-XX is too thin for the UK and is not on the recommended table.

I'd go with what Marc says. There's a reason manufacturer's spec a specific oil, if it was as easy as just using a thinner 'winter' oil spec as possible then they'd have spec'd it that way in the first place. Oils have to do more than just lubricate, another function is moving heat around an engine to aid cooling. It's undoubtedly possible to use a thinner 'winter' oil, but you'd (theoretically at least) be restricted in what stresses you could put your engine through. An engine is spec'd to use specific oils as that engine has to be able to cope through its entire planned operating range - heat / cold / rev range / engine temperatures / acceleration / etc, etc.

[faddy]

I have to admit I asked the question expecting the answer "yes" (0W40 ok). Reading around a bit it seems that any multigrade oil at low temperature is thicker than at operating temperature (so at low temperature a 0W40 is thinner than a 5W40 but still thicker than either is in a hot engine). Certain if you look at the table for Cit petrol engines the 1.0i which can run on 15W40 can also use 10W40 or 5W40, the 1.6i which runs on 5W30 can also use 0W30 and the 1.8i and 2.2i which run on 10W40 can also use 5W40. It's only my 2.0i for which a lower winter weight alternative isn't shown.

I've seen it suggested (source admittedly being "some blokes on the internet") that manufacturers tend not to specify 0W40 oils as they're unnecessarily expensive premium oils. For what it's worth Mobil themselves suggest for my engine Mobil Super™ 3000 X1 5W-40 for "Everyday Protection" or Mobil Super™ 3000 X1 5W-40 (the stuff that Costco do) for "Ultimate Performance" and several others including a synthetic 5W50 for high (>100,000km) mileage engines and even a couple of semi synth 10W40's. On the other hand Total, who also sell a 0W40 oil only recommend their 5W40.

In terms of specifications am I correct that their are no specific PSA/Citroen specs akin to those set by e.g. VW, and that the only things therefore to look for are the grade, the ACEA classification, and whether it's synthetic or semi?

[EDC5]

I have to admit I asked the question expecting the answer "yes" (0W40 ok). Reading around a bit it seems that any multigrade oil at low temperature is thicker than at operating temperature (so at low temperature a 0W40 is thinner than a 5W40 but still thicker than either is in a hot engine). Certain if you look at the table for Cit petrol engines the 1.0i which can run on 15W40 can also use 10W40 or 5W40, the 1.6i which runs on 5W30 can also use 0W30 and the 1.8i and 2.2i which run on 10W40 can also use 5W40. It's only my 2.0i for which a lower winter weight alternative isn't shown.

I've seen it suggested (source admittedly being "some blokes on the internet") that manufacturers tend not to specify 0W40 oils as they're unnecessarily expensive premium oils. For what it's worth Mobil themselves suggest for my engine Mobil Super™ 3000 X1 5W-40 for "Everyday Protection" or Mobil Super™ 3000 X1 5W-40 (the stuff that Costco do) for "Ultimate Performance" and several others including a synthetic 5W50 for high (>100,000km) mileage engines and even a couple of semi synth 10W40's. On the other hand Total, who also sell a 0W40 oil only recommend their 5W40.

In terms of specifications am I correct that their are no specific PSA/Citroen specs akin to those set by e.g. VW, and that the only things therefore to look for are the grade, the ACEA classification, and whether it's synthetic or semi?

Citroen definitely have their own specs, not sure for petrol engines but my HDi needs to meet PSA B71 2290, available oils listed here: https://www.opieoils.co.uk/c-1493-citro ... e-oil.aspx

[GiveMeABreak]

The specs are on the WIKI.

https://frenchcarforum.co.uk/wiki/index ... arbox_Oils

Scroll down to section 6 and they are listed under ‘PSA Peugeot Citroen norms’

[bobins]

There are PSA specs for vehicles built after mid February 2009, but prior to that they use ACEA specs.

Correct oil specs is a bit involved. If you promise to NEVER run your vehicle in very cold conditions or hot conditions, AND promise to never rev it to more than about 75% of max RPM, AND promise to never load it more than about 75% of MAM, and/or tow a trailer/caravan, AND promise to only use top quality fuels, AND promise to change the oil well within the specified service intervals AND give it a proper service, AND promise that you're not too fussed about what may happen after you've driven about another 50k, AND you're not overly concerned about MPG, then you could probably use just about any old motor oil. If you're a bit doubtful about keeping to those limitations then it might be wise to stick with the specified oil. Oils are (relatively) cheap - engines are expensive.

[xantia_v6]

It may not be so relevant now, but historically, oils with a wide viscosity range achieved that by having a rather thin base oil and then lots of thickener additives to bring the hot viscosity up to spec. The problem with this is that the thickeners tend to wear out, meaning that the oil gets thinner with age, and so should be changed more often. Maybe the reluctance to recommend 0W-XX oils is because they are not reliable with extended service intervals?

[faddy]

There are PSA specs for vehicles built after mid February 2009, but prior to that they use ACEA specs.

Which explains why there's no mention in my 2008 maintenance guide.

[GiveMeABreak]

Page 21 and 22 should have it - I've arrowed the relevant bits in Red:

Click to Zoom

So if you have a 2.0 Petrol:
Oil Grade: 5W-40
PSA Specs: B71 2296