49 replies to this topic

[oilman]

Hi all, Around this time of year we get quite a few questions about experiencing difficult gearshifts in cold weather, so we thought you might find this useful. Using the incorrect viscosity gear oil in your car can make gear changes very difficult when the gearbox, and oil are cold. This is why we often don't recommend using thicker gear oils than the manufacturer specifies. It is easy to think that increasing the viscosity from a 75w-80 to 75w-90 or 75w-90 to 75w-140 isn't going to affect the cold properties of the oil, but it does. Below are some figures showing the viscosity of a selection of oils at 40C measured in mm²/s ( 1 millimeter²/second = 1 centistoke, A centistoke is a decimal fraction of the CGS unit of kinematic viscosity stokes, which is equal to centimeter per second (cm²/s). 1 stokes is a kinematic viscosity of a fluid with a density of 1 g/cm³ and a dynamic viscosity of 1 poise… In short the thickness of oil!). 40degc may not seem cold but this is the temperature at which the viscosity is measured and is the information you will find on the oil technical data sheets. I have listed specific brands and products to make it easier to see the differences in viscosity. Fuchs Sintofluid FE 75w = 40.8 @ 40°c Fuchs Sintofluid 75w-80 = 49.8 @ 40°c Fuchs Sintopoid 75w-90 = 90.5 @ 40°c Fuchs Sintopoid LS 75w140 = 170 @ 40°c As you can see from that, they are all 75w oils, but there is a large difference in the viscosity at lower temps; the Sintopoid 75w-90 is over twice as thick as the Sintofluid FE 75w when cold and the 75w-140 is almost twice as thick as the 75w-90. So, if you've got a car that needs one grade of oil as standard, but you've modified it and decide to try a thicker oil, or someone puts the wrong oil in, it might really affect the cold gear shifts. Usually, increasing the quality is a better option than increasing the viscosity when thinking about upgrading from standard fluid. Also, viscosity ratings are not exact points, but are a band that the viscosity should fall in. The Motul Gear 300 75w-90 has a viscosity of 76.2mm²/s at 40°c and the Castrol Universal 75w-90 is 84.8mm²/s, so you can see there is some variation in oils that appear to be the same viscosity. A lot of gearboxes specify an 80w-90 rather than a 75w-90, but I would always tend to go for a 75w-90 instead as there can be a large difference is the viscosity when cold. The Motul Gearbox 80w-90 is 164mm²/s, so over twice as thick as their Gear 300 when cold. If you're using an 80w-90 and are having stiff cold gear changes, changing to a 75w-90 is likely to improve things. If you have any questions or need further advice please post here or email us at sales@opieoils.co.uk Cheers Tim.

[JG]

lots of useless drivel lots of useless drivel lots of useless drivel lots of useless drivel lots of useless drivel Buy our oil lots of useless drivel lots of useless drivel lots of useless drivel

[Andrew aka Stuwy]

I had a little odd thing changing gear in the cold... engine mount incerts fixed that..

[oilman]

lots of useless drivel
lots of useless drivel
lots of useless drivel
lots of useless drivel
lots of useless drivel
Buy our oil
lots of useless drivel
lots of useless drivel
lots of useless drivel

Are you really a moderator? If so, I find that quite worrying...

You sound more like an idiot in a playground

Cheers

[Lou_m]

Thanks for posting. The wife's Seat Ibiza FR 1.8T gearbox is a bit notchy going from 1st to 2nd above 4k rpm. Lots of advice seems to be to change the oil. Do you know if this is a common problem?

[fezzasus]

40degc may not seem cold but this is the temperature at which the viscosity is measured and is the information you will find on the oil technical data sheets.

It's quoted at 40 deg. C for manufacturing plants to know how to handle it. It's not for a technical application of the oil.

Your advice is mainly correct, however I would suggest to you that it costs about £20 to run a KV at any temperature, if you want to provide useful data to explain which oil someone should pick, i'd spend that £20 per gear oil to have a KV measured at 0 deg. C, or even -10 deg. C to actually rank them at a temperature where shifting becomes an issue. This is because temperature responses are rarely linear due to the different solubilities of the oils and additives so the relative viscosities at 40 deg. C don't translate to lower temps.

[Stik]

Other than being annoying are stiff cold gearchanges a problem? I'm always a bit wary of forcing it into first in the cold. I live at the top of a big hill so maybe i should just leave it parked in 2nd and roll down the first bit

[Goosenka]

40degc may not seem cold but this is the temperature at which the viscosity is measured and is the information you will find on the oil technical data sheets.

It's quoted at 40 deg. C for manufacturing plants to know how to handle it. It's not for a technical application of the oil.

Your advice is mainly correct, however I would suggest to you that it costs about £20 to run a KV at any temperature, if you want to provide useful data to explain which oil someone should pick, i'd spend that £20 per gear oil to have a KV measured at 0 deg. C, or even -10 deg. C to actually rank them at a temperature where shifting becomes an issue. This is because temperature responses are rarely linear due to the different solubilities of the oils and additives so the relative viscosities at 40 deg. C don't translate to lower temps.

Could not have put it better myself. Thanks Fezz

[JG]

He just put it in a slightly more polite way than me For the majority of vx owners, cold gear selection has absolutely nothing to do with gearbox oil and all to do with cable issues.

[JG]

lots of useless drivel
lots of useless drivel
lots of useless drivel
lots of useless drivel
lots of useless drivel
Buy our oil
lots of useless drivel
lots of useless drivel
lots of useless drivel

:P/>

Are you really a moderator? If so, I find that quite worrying...

You sound more like an idiot in a playground :rolleyes:/>

Cheers

Yeah and you're selling crack at the gate under the pretence that it's Sherbet

[slindborg]

He just put it in a slightly more polite way than me

For the majority of vx owners, cold gear selection has absolutely nothing to do with gearbox oil and all to do with cable issues.

BINGO!!!

But all the first post will be on all the fora 'he' posts on and if it gets a few sales from numpties then so be it.

I do love the dopey adverts on Motors Tv, its like they spent a whole 10pence on it

[Bargi]

lots of useless drivel
lots of useless drivel
lots of useless drivel
lots of useless drivel
lots of useless drivel
Buy our oil
lots of useless drivel
lots of useless drivel
lots of useless drivel

:P/>

Are you really a moderator? If so, I find that quite worrying...

You sound more like an idiot in a playground :rolleyes:/>

Cheers

Yeah and you're selling crack at the gate under the pretence that it's Sherbet ;)/>

Tsk, tsk JG. What happened to your "If I've got nothing nice to say..."

[JG]

Ah yes, it ran out, I'll go and put it on charge. I will point out two things though: my first post had a in it and I could have been far less nice

[oilman]

40degc may not seem cold but this is the temperature at which the viscosity is measured and is the information you will find on the oil technical data sheets.

It's quoted at 40 deg. C for manufacturing plants to know how to handle it. It's not for a technical application of the oil.

Your advice is mainly correct, however I would suggest to you that it costs about £20 to run a KV at any temperature, if you want to provide useful data to explain which oil someone should pick, i'd spend that £20 per gear oil to have a KV measured at 0 deg. C, or even -10 deg. C to actually rank them at a temperature where shifting becomes an issue. This is because temperature responses are rarely linear due to the different solubilities of the oils and additives so the relative viscosities at 40 deg. C don't translate to lower temps.

Thanks for the additional info fezzasus, I will look further into that.

Cheers

[oilman]

Other than being annoying are stiff cold gearchanges a problem? I'm always a bit wary of forcing it into first in the cold. I live at the top of a big hill so maybe i should just leave it parked in 2nd and roll down the first bit

No, it will do no harm as long as nothing is forced.

Cheers

[oilman]

He just put it in a slightly more polite way than me

For the majority of vx owners, cold gear selection has absolutely nothing to do with gearbox oil and all to do with cable issues.

Maybe so, and I dont doubt there are cable issues. This is just general info, for those that are interested.

Cheers

[oilman]

lots of useless drivel
lots of useless drivel
lots of useless drivel
lots of useless drivel
lots of useless drivel
Buy our oil
lots of useless drivel
lots of useless drivel
lots of useless drivel

:P/>

Are you really a moderator? If so, I find that quite worrying...

You sound more like an idiot in a playground :rolleyes:/>

Cheers

Yeah and you're selling crack at the gate under the pretence that it's Sherbet

Ok, you got me there... Hmmm sherbet

Cheers

[oilman]

He just put it in a slightly more polite way than me

For the majority of vx owners, cold gear selection has absolutely nothing to do with gearbox oil and all to do with cable issues.

BINGO!!!

But all the first post will be on all the fora 'he' posts on and if it gets a few sales from numpties then so be it.

I do love the dopey adverts on Motors Tv, its like they spent a whole 10pence on it

If I get sales from it then ideal, but not sure how I would know that... This is a general info post, there are not links to my site etc. We make many other posts that are very much sales focussed with offers, competitions etc.

Glad you like my adds I dont have Morrison's budget yet, but one day eh. I will say that the tv advertising works though.

Cheers

Guy

[slindborg]

How can it be anything other than an advertising post... lots of stuff to baffle the masses and then your sig with links to the shop as if by magic people will go there and buy (if they are panicked enough) Get Richard Hammond to walk around your shop for the next tv ad.

[oilman]

How can it be anything other than an advertising post...

That is quite simple... This is an advertising post http://www.vx220.org...oon-25-off-rrp/

My first post on this thread does not state any prices, recommendations, discounts, links etc. It is just information. To me there is quite a difference.

lots of stuff to baffle the masses

Do you not understand it?

and then your sig with links to the shop as if by magic people will go there and buy (if they are panicked enough)

What are they going to buy if the masses are baffled? I have not suggested anything.

Yes my sig has links in it, this seems to be acceptable here. Mr Moderator JG has commercial links in his sig, does that mean every post he makes is an advertising post?

Cheers