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Car Forum / MINI / December 2003mini auto - what the right oil?
I have a 69 minimatic with about 20,000 miles on the clock. I've had it since new and always used Castrol GTX (the original 20-50w)for oil. When its cold it changes gears beautifully, when it gets hot the changes get alot clunkier. The oil pressure also tends to drop when its hot (from 70 to 50lbs). I presume the oil is thinning out and is affecting the quality of changes. With all the new oils around today has anyone used a 15-60w or synthetic to improve oil pressure when its hot? Has this improved gear changing? Don't believe I have a mechanical problem as its behaved like this for ever. I'm about to change the oil so thought it would be a good time to ask. do not use synthetic in a mini it will ruin the gearboc makka > I have a 69 minimatic with about 20,000 miles on the clock. I've had > it since new and always used Castrol GTX (the original 20-50w)for oil. [quoted text clipped - 7 lines] > ever. > I'm about to change the oil so thought it would be a good time to ask. > > I have a 69 minimatic with about 20,000 miles on the clock. 120,000? 220,000? Or has it been hiding somewhere??? Thats about 1.6 miles per day! > > I've had it since new I guess if you say it's 20,000 then it really is! Seriously what have you been doing with it that it's done so little distance? > > and always used Castrol GTX (the original 20-50w)for oil. > > When its cold it changes gears beautifully, when it gets hot the > > changes get alot clunkier. The oil pressure also tends to drop when > > its hot (from 70 to 50lbs). These facts suggest it might benefit from a heavier weight oil. > > I presume the oil is thinning out and is affecting the quality of changes. With > > all the new oils around today has anyone used a 15-60w or synthetic to improve > > oil pressure when its hot? Has this improved gear changing? I'd be inclined to try the 15-60 if you can get it locally. > > Don't believe I have a mechanical problem as its behaved like this for > > ever. > > I'm about to change the oil so thought it would be a good time to ask. What you do want to avoid in the Minimatic is any form of "friction modified" oil, because of the effect this has on the numerous wet friction elements (2 clutches, 3 bands) in the gearbox. In fact if you want to spend money on really good oil, a thicker motorcycle oil designed for bikes which mostly have wet clutches is probably the go. > do not use synthetic in a mini it will ruin the gearboc Earth to Makka: this is an auto. The box bears no resemblance whatsoever to your manual Mini gearbox. > I have a 69 minimatic with about 20,000 miles on the clock. I've had > it since new and always used Castrol GTX (the original 20-50w)for oil. [quoted text clipped - 7 lines] > ever. > I'm about to change the oil so thought it would be a good time to ask. Know someone that had a auto always used castrolite oil no problems - what does the manual recommend? hiya Makka is right only use ordinary mineral oil.. fragged > I have a 69 minimatic with about 20,000 miles on the clock. I've had > it since new and always used Castrol GTX (the original 20-50w)for oil. [quoted text clipped - 7 lines] > ever. > I'm about to change the oil so thought it would be a good time to ask. > hiya > Makka is right only use ordinary mineral oil.. > > fragged The oil that was good (good oil) was castrol XL and the lighter version was Castrolite. I buggered an engine and gearbox (MGB) (MG's run engine oil in the gearbox) on GTX not nearly the oil of its predecessors XL or Lite. >>I have a 69 minimatic with about 20,000 miles on the clock. I've had >>it since new and always used Castrol GTX (the original 20-50w)for oil. [quoted text clipped - 7 lines] >>ever. >>I'm about to change the oil so thought it would be a good time to ask. I change the oil in my Mitsubishi Galant VR4 every 5,000 k's, the mobil 1 that comes out of it gets poured straight into my mini clubman motorsport hack, i,ve never had a problem with it, gearbox is still as it was rebuilt. Mobil 1 is fully synthetic, go figure?????? Doogie > > hiya > > Makka is right only use ordinary mineral oil.. [quoted text clipped - 17 lines] > >>ever. > >>I'm about to change the oil so thought it would be a good time to ask. hi I will never use a synthetic again as both my bro'in'law and myself have blown gearboxes using the stuff. fragged > I have a 69 minimatic with about 20,000 miles on the clock. I've had > it since new and always used Castrol GTX (the original 20-50w)for oil. [quoted text clipped - 7 lines] > ever. > I'm about to change the oil so thought it would be a good time to ask. hello to the group! what's this about synthetic causing blown gearboxes ??? how does this happen I thought oil was oil ok I no 1 is mineral and the other synthetic <man-made?> but can it really cause damage? mark in the uk/........... > hi > I will never use a synthetic again as both my bro'in'law and myself have [quoted text clipped - 13 lines] > > ever. > > I'm about to change the oil so thought it would be a good time to ask. oh yes it can trust me, in a mini box the wrong oil can do some damage. > hello to the group! > what's this about synthetic causing blown gearboxes ??? > how does this happen I thought oil was oil ok I no 1 is mineral and > the other synthetic <man-made?> but can it really cause damage? Not sure exactly how it works, but assume it's something to do with how the big strings of hydrocarbons are built, and how they react when being 'munched' up by whirring gears. Perhaps the abuse of a mini gearbox will thicken/thin the oil up the the point where there isn't enough/there's too much of it in the right/wrong place? ( bases = covered :) ) I guess it's more likely a case of thickening up? That said, don't some of the Metro's and the ERA turbo's specify SemiSynthetic oils - it can't be thattt bad?? I know some folk who've had issues with those snake oil like compounds known as X1R and MotorUp in mini's... and in NZ I've seen one mini box that was the sad victim of 'Morey's PowerBooster' - the remains of the box being full of a treacle like substance. Meh! - Mineral oil is cheaper anyhow :) splam. > That said, don't some of the Metro's and the ERA turbo's specify > SemiSynthetic oils - it can't be thattt bad?? Turbo's run on a bearing of oil and generate enormous heat. The heat is enough to break down mineral oil causing it to leave carbon deposits and damage the bearings, that's why most Turbo's run fully synthetic. Shaun. And Elvis was sitting next to splam in the spaceship, which I thought was kinda weird, but then they turned to me and said: > > hello to the group! > > what's this about synthetic causing blown gearboxes ??? [quoted text clipped - 4 lines] > big strings of hydrocarbons are built, and how they react when being > 'munched' up by whirring gears. Almost. It's the fact that there are preloaded roller bearings in the diff. Synthetic oils tend to be pretty poor at coping with extreme point pressures. A synthetic is typically made from a much thinner base oil with fancy hi- tec molecules added that are designed to temporarily bind together under pressure to increase the effective viscosity and film strength of the oil. That gives you an oil that is thin, so flows freely, but 'thickens up' once it's inside bearings or between sliding surfaces. The problem is with that parts that have very small point contact under high pressure. the molecules can't bind together under extreme pressure, so effectively the only lubrication is the thin base oil. The parts in the Mini gearbox that suffer most are the large crownwheel bearings and the baulk rings in the synchro hubs.  Signature(-AD-) > > hello to the group! > > what's this about synthetic causing blown gearboxes ??? [quoted text clipped - 22 lines] > > splam. May I point you to our web site on this thread? (www.dsnclassics.co.uk) In the technical section, there is an official response from Castrol on this very subject. We were always being asked about fancy expensive oils and why we only sell basic 20W/50. The main reason for not using most synthetic oils is because they are designed for modern engines that can cope with lower viscocities. The A series certainly needs a denser oil than modern units. In my view, you should be carrying out oil and filter changes every 6,000 miles on a manual and every 3,000 on an auto anyway. In this time the cheaper oil won't have degraded too much anyway. So why pay out for expensive stuff? SignatureRgds Steve steve@dsnclassics.co.uk www.dsnclassics.co.uk MiniChicago wrote:12/11/03 10:54 AM On my old motorcycles past and present synthetic oil ate up the seals very quickly. On the newer machines, mid 80's and newer there is no problem. Maybe the thickening up in the gear box it the mixtures of corroding rubber with the synthetic oil. That could clog things up. >>> hello to the group! >>> what's this about synthetic causing blown gearboxes ??? [quoted text clipped - 37 lines] > cheaper oil won't have degraded too much anyway. So why pay out for > expensive stuff? mark williams wrote: > hello to the group! > what's this about synthetic causing blown gearboxes ??? > how does this happen I thought oil was oil ok I no 1 is mineral and the > other synthetic <man-made?> but can it really cause damage? >>hi >> I will never use a synthetic again as both my bro'in'law and myself have [quoted text clipped - 13 lines] >>>ever. >>>I'm about to change the oil so thought it would be a good time to ask. This is what it reads in the workshop manual Minimatic Engine and automatic transmission. Multigrade oil only SAE 10W/30 SAE 10W/40 SAE 20W/50 Additives to the above oils MUST NOT be used under any circumstances in the Mini Matic and are not necessary or desirable in manual transmission vehicles. I think that you will find that modern oils contain additives hence the SF SE etc ratings and specialist oils for turbos etc. one of the first was in the castrol range was GTX (early 70's). I do think these oils are a high detergent oils. Oil for diesel's is a not detergent oil. (MAKKA) You now buy oils for older cars, which I use for the Mini's and MG's, so oil companies must have found problems with modern oils in older cars. As I stated before GTX buggered my MGB (5000 miles) the bigend bearing were run and the races in the gearbox were blue - This was from a rebuild of both engine and gearbox and intoduced them straight to GTX. The car had 120000 miles and had always used Castrol XL previously. Anyhow - Ill leave that thought with you. hello again, well that explains my question! I will be changing the oil at the weekend then , as i have being running > mark williams wrote: > [quoted text clipped - 48 lines] > > Anyhow - Ill leave that thought with you. > hello again, well that explains my question! > I will be changing the oil at the weekend then , as i have being running > semi synth.........oops! but its only been about 500 miles so should be ok! If it is of a suitable viscosity, don't worry. You only need to change it if it isn't the correct spec. SignatureRgds Steve steve@dsnclassics.co.uk www.dsnclassics.co.uk cheers Steve, but I will change it anyway for 20w/50 mark.w > > hello again, well that explains my question! > > I will be changing the oil at the weekend then , as i have being running [quoted text clipped - 3 lines] > If it is of a suitable viscosity, don't worry. You only need to change it if > it isn't the correct spec. good man, another convert :-) I use millers classic in mine. fragged > I have a 69 minimatic with about 20,000 miles on the clock. I've had > it since new and always used Castrol GTX (the original 20-50w)for oil. [quoted text clipped - 7 lines] > ever. > I'm about to change the oil so thought it would be a good time to ask. |
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