markievw 0 Posted May 29, 2005 hi have an m plate vr6 corrado, what oil should i use in her? mark Quote Share this post Link to post Share on other sites
vr6storm 0 Posted May 29, 2005 do a search.....its been done to death :D Quote Share this post Link to post Share on other sites
DaveStorm 0 Posted May 29, 2005 Go for VW's own synta silver if you can't be arsed to search :wink: Quote Share this post Link to post Share on other sites
Blue_Joe 0 Posted May 29, 2005 Only VW Synta Silver Quote Share this post Link to post Share on other sites
oilman 0 Posted June 1, 2005 Any VW Approved 5w-40 or 10w-40 will be fine. Cheers Guy Quote Share this post Link to post Share on other sites
Kevin Bacon 5 Posted June 1, 2005 If your VR6 is getting on a bit (100K +), you're better off with Castrol Magnatec 15W-40, which is VW 501 approved. Quote Share this post Link to post Share on other sites
StormVR6 0 Posted June 1, 2005 Hmm I agree, I think 5w/40 will be too thin (esp. on an older engine) I find 10w/40 Shell Oil to be excellent in my engine and it doesn't cost the earth! Quote Share this post Link to post Share on other sites
oilman 0 Posted June 1, 2005 I read on many forums about 0w and 5w oils being too thin. I will try to explain it without getting over technical and we'll go from there. 0w-40, 5w-40, 10w-40 and 15w-40 are all the same thickness (14cst) at 100degC. Centistokes (cst) is the measure of a fluid's resistance to flow (viscosity). It is calculated in terms of the time required for a standard quantity of fluid at a certain temperature to flow through a standard orifice. The higher the value, the more viscous the fluid. As viscosity varies with temperature, the value is meaningless unless accompanied by the temperature at which it is measured. In the case of oils, viscosity is generally reported in centistokes (cst) and usually measured at 40degC and 100degC. So, all oils that end in 40 (sae 40) are around 14cst thickness at 100degC. This applies to all oils that end in the same number, all oils that end in 50 (sae 50) are around 18.5cst at 100degC and all oils that end in 60 (sae 60) are around 24cst at 100degC. With me so far? Great! Now, ALL oils are thicker when cold. Confused? It's true and here is a table to illustrate this. SAE 40 (straight 40) Temp degC.........................Viscosity (thickness) 0..........................................2579cst 20..........................................473cst 40..........................................135cst 60..........................................52.2cs t 100........................................ 14cst 120.........................................8.8cst As you will see, there is penty of viscosity at 0degC, in fact many times more than at 100degC and this is the problem especially in cold weather, can the oil flow quick enough to protect vital engine parts at start up. Not really! So, given that an sae 40 is 14cst at 100degC which is adequate viscosity to protect the engine, and much thicker when cold, how can a 0w oil be too thin? Well, it can't is the truth. The clever part (thanks to synthetics) is that thin base oils can be used so that start up viscosity (on say a 5w-40 at 0degC) is reduced to around 800cst and this obviously gives much better flow than a monograde sae 40 (2579cst as quoted above). So, how does this happen, well as explained at the beginning, it's all about temperature, yes a thin base oil is still thicker when cold than at 100degC but the clever stuff (due to synthetics again) is that the chemists are able to build these oils out of molecules that do not thin to less than 14cst at 100degC! What are the parameters for our recommendations? Well, we always talk about good cold start protection, by this we mean flow so a 5w will flow better than a 10w and so on. This is why we recommend 5w or 10w as the thickest you want to use except in exceptional circumstances. Flow is critical to protect the engine from wear! We also talk about oil temps, mods and what the car is used for. This is related to the second number xw-(XX) as there may be issues with oil temperatures causing the oil to be too thin and therefore the possibility of metal to metal contact. This is difficult to explain but, if for example your oil temp does not exceed 120degC at any time then a good "shear stable" sae 40 is perfectly capable of giving protection. "Shear stability" is important here because if the oil shears it thins and that's not good! However, if you are seeing temperatures in excess of 120degC due to mods and track use etc then there is a strong argument to using an sae 50 as it will have more viscosity at these excessive temperatures. There are trade offs here. Thicker oils cause more friction and therefore more heat and they waste power and affect fuel consumption so it's always best to use the thinnest oil (i.e. second number) that you can get away with and still maintain oil pressure. There is more but this post is too long already so lets keep it to basics. Cheers Guy Quote Share this post Link to post Share on other sites
RW1 0 Posted June 1, 2005 This is why we recommend 5w or 10w as the thickest you want to use except in exceptional circumstances. Flow is critical to protect the engine from wear! So, please explain why have I seen so many Corrado oil pump failures due to wear over the years. When the owner is asked about the oil used... "I've always used 0w40 (or 5w40)?" And the pump failure seems more when using 0w40 Mobil 1. The failures are either the gears wearing or the pressure relief valve jamming due to rattling wear profiles forming. Mileages - 50k to 70k miles. The Corrado handbook and VW Corrado maintenance manual states 15W40 for ambient temps -10 to +30'C. 10w40 is -15 to +15'C. Quote Share this post Link to post Share on other sites
oilman 0 Posted June 1, 2005 I don't think you'll find that it's down to the oil. Cheers Guy Quote Share this post Link to post Share on other sites
RW1 0 Posted June 1, 2005 If your VR6 is getting on a bit (100K +), you're better off with Castrol Magnatec 15W-40, which is VW 501 approved. I'll stick with Kevin's line, summer running at idle 2bar, 4 bar at 2,000 rpm, even if it's only done 37K. Quote Share this post Link to post Share on other sites
StormVR6 0 Posted June 1, 2005 Oilman your grasp of engine oil properties is very impressive but at the end of the day 0/40 or 5/40 is not advisable for a VR6 for many reasons which I am not prepared to take time jotting down, yes a brand new engine would benefit from a "thinner" oil due to all components being tight but on a older engine I would think a higher grade oil would be more beneficial. All "old" engines are supposedly better on 20w/50 for this reason. And due to the VR6 not having valves etc tightly packed I don't think 0w/40 is needed as friction would be nowhere near as much as on say a new R32 unit which would definately want a lower grade. Just my opinion MB Quote Share this post Link to post Share on other sites
Christoph 0 Posted June 2, 2005 Hold on, I'm confused now. Does a SAE 5 oil have a higher or lower viscosity than a SAE 40 oil at the same temperature? Chris 94 VR6 Quote Share this post Link to post Share on other sites
oilman 0 Posted June 2, 2005 The first number "w" is cold crank viscosity (0w,5w,10w etc) the second number is the sae number (20,30,40,50 etc). The second number is the one that determines the viscosity to which the oil thins, normally measured at 100degC. i.e. sae 40 = 14cst, sae 50 = 18.5cst, sae 60 = 24cst. Depending on the first number "w" the degree of thickness at which the oil starts is determined and the second number is the minimum viscosity to which it thins too. All oils are thicker when cold, here are some examples that illustrate what actually happens to the oil with temperature. 0w-20..at.......... 0degC = 328......at 10degC = 181......at 100degC = 9 5w-40..at ........................811........................421..........................14 10w-50.at.......................1039........................539.........................18.5 15w-50.at.......................1376........................675.........................18.5 20w-50.at.......................2305.......................1015........................18.5 Obviously the thinner the oil the better the flow at 0degC and 10degC. Hope this explains. Cheers Guy Quote Share this post Link to post Share on other sites
Kevin Bacon 5 Posted June 2, 2005 At the end of the day, as consumers....what dictates the oil we use is how much is left on the dipstick with each monthly check, and I think I can speak on behalf of the forum that a 0-40W would be at the minimum mark, whereas a 10 or 15/40W should still be around the max mark....assuming the engine is healthy and all variables the same. Quote Share this post Link to post Share on other sites
oilman 0 Posted June 2, 2005 Here's a copy of the lubricants report for your vehicles. Volkswagen, Corrado Manufacturer: Volkswagen AG, Wolfsburg, Germany Engine AAA Corrado VR6 - 2.8 Petrol, 4-stroke, 6 cylinder, VR, 2 valves/cil., liquid cooled Cylinder capacity: 2792 cc Power output: 180 HP/132 kW at 5800 RPM Capacity: 6 liter Filter capacity: 1 liter Use: normal Change 15000 km/12 months OEM recommendation Above -15 VW 501.01 SAE 15W-40 Above -15 VW 501.01 SAE 15W-50 From -20 to 15 VW 501.01 SAE 10W-30 From -20 to 15 VW 501.01 SAE 10W-40 Below -10 VW 501.01 SAE 5W-30 Below -10 VW 501.01 SAE 5W-20 year-round VW 500.00 SAE 10W-30 year-round VW 500.00 SAE 10W-40 year-round VW 500.00 SAE 10W-50 year-round VW 500.00 SAE 5W-40 year-round VW 500.00 SAE 5W-50 If VW approved motoroils are not available, API: SF or SG oils may be used occasionally. Engine PG Corrado G 60 , Corrado 1.8i G60 Petrol, 4-stroke, 4 cylinder, Line, 2 valves/cil., Turbo, liquid cooled Cylinder capacity: 1781 cc Power output: 160 HP/118 kW at 5600 RPM Capacity: 4 liter Filter capacity: 1 liter Use: normal Change 15000 km/12 months OEM recommendation Above -15 VW 501.01 SAE 15W-40 Above -15 VW 501.01 SAE 15W-50 From -20 to 15 VW 501.01 SAE 10W-30 From -20 to 15 VW 501.01 SAE 10W-40 Below -10 VW 501.01 SAE 5W-30 Below -10 VW 501.01 SAE 5W-20 year-round VW 500.00 SAE 10W-30 year-round VW 500.00 SAE 10W-40 year-round VW 500.00 SAE 10W-50 year-round VW 500.00 SAE 5W-40 year-round VW 500.00 SAE 5W-50 If VW approved motoroils are not available, API: SF or SG oils may be used occasionally. Engine 9A Corrado 2.0i 16V Petrol, 4-stroke, 4 cylinder, Line, 4 valves/cil., liquid cooled Cylinder capacity: 1984 cc Power output: 136 HP/100 kW at 5800 RPM Capacity: 4 liter Filter capacity: 0.25 liter Use: normal Change 15000 km/12 months OEM recommendation Above -15 VW 501.01 SAE 15W-40 Above -15 VW 501.01 SAE 15W-50 From -20 to 15 VW 501.01 SAE 10W-30 From -20 to 15 VW 501.01 SAE 10W-40 Below -10 VW 501.01 SAE 5W-30 Below -10 VW 501.01 SAE 5W-20 year-round VW 500.00 SAE 10W-30 year-round VW 500.00 SAE 10W-40 year-round VW 500.00 SAE 10W-50 year-round VW 500.00 SAE 5W-40 year-round VW 500.00 SAE 5W-50 If VW approved motoroils are not available, API: SF or SG oils may be used occasionally. Engine ABV Corrado VR6 - 2.9 Petrol, 4-stroke, 6 cylinder, VR, 2 valves/cil., liquid cooled Cylinder capacity: 2861 cc Power output: 190 HP/140 kW at 5800 RPM Capacity: 6 liter Filter capacity: 1 liter Use: normal Change 15000 km/12 months OEM recommendation Above -15 VW 501.01 SAE 15W-40 Above -15 VW 501.01 SAE 15W-50 From -20 to 15 VW 501.01 SAE 10W-30 From -20 to 15 VW 501.01 SAE 10W-40 Below -10 VW 501.01 SAE 5W-30 Below -10 VW 501.01 SAE 5W-20 year-round VW 500.00 SAE 10W-30 year-round VW 500.00 SAE 10W-40 year-round VW 500.00 SAE 10W-50 year-round VW 500.00 SAE 5W-40 year-round VW 500.00 SAE 5W-50 If VW approved motoroils are not available, API: SF or SG oils may be used occasionally. Transmission, automatic Corrado 1.8i G60 , Corrado 2.0i 16V , Corrado VR6 - 2.8 , Corrado VR6 - 2.9 Automatic Capacity: 3 liter Gears forward: 4 Gears reverse: 1 Use: normal Change 60000 km OEM recommendation year-round Dexron IID - Transaxle, manual Corrado VR6 - 2.9 Manual Capacity: 2 liter Gears forward: 5 Gears reverse: 1 Use: normal OEM recommendation year-round VW G 51 SAE 75W-90 Differential, from automatic Corrado 1.8i G60 , Corrado 2.0i 16V , Corrado VR6 - 2.8 , Corrado VR6 - 2.9 Capacity: 0.75 liter Use: normal OEM recommendation year-round VW G 052 145 SAE 75W-90 Transaxle, manual Corrado G 60 , Corrado 1.8i G60 , Corrado 2.0i 16V , Corrado VR6 - 2.8 Manual Capacity: 2 liter Gears forward: 5 Gears reverse: 1 Use: normal OEM recommendation year-round VW G 50 SAE 75W-90 Hydraulic brakes/clutch system Corrado 1.8i G60 , Corrado 2.0i 16V , Corrado VR6 - 2.8 , Corrado VR6 - 2.9 Capacity: Use: normal Change 24 months OEM recommendation year-round Brake Fluid DOT 4+ - Hydraulic Brake System Corrado G 60 Capacity: Use: normal Change 24 months OEM recommendation year-round Brake Fluid DOT 4+ - Power steering Corrado G 60 , Corrado 1.8i G60 , Corrado 2.0i 16V , Corrado VR6 - 2.8 , Corrado VR6 - 2.9 Capacity: Use: normal Check 60000 km OEM recommendation year-round VW G 002 000 - Cooling system Corrado G 60 , Corrado 1.8i G60 , Corrado 2.0i 16V , Corrado VR6 - 2.8 , Corrado VR6 - 2.9 Capacity: 5 - 8.2 liter Use: normal Check 500 km Change 60000 km/24 months OEM recommendation year-round Water with antifreeze (40%) - Water with 40% VW Anti Freeze G 011 V8C, to specification TL-VW 774C. Cheers Guy Quote Share this post Link to post Share on other sites
coolrado 0 Posted June 2, 2005 my 91 g60 on 120k has always been run on either synta silver or shell helix 10w40 according to the mass of vw receipts i got with it, and the oil level hasnt dropped any more than a couple of mm in months. i have still got the same refill tub of synta since i have had the car (obviously done a few oil changes in the last couple of years ) but have hardly had to top it up more than a dribble and i do push the car quite hard. so im going to stick with what its allways been fed as it seems to have served it well so far Quote Share this post Link to post Share on other sites
Yandards 0 Posted June 2, 2005 Guy you don't work for Castrol do you? :) Going to stick with the recommend oil as listed by VW, until I start having to top the oil up there is little point in putting a thicker grade in. Quote Share this post Link to post Share on other sites
dr_mat 0 Posted June 2, 2005 Interesting stuff. I finally understand the viscosity measurement. No doubt I will instantly forget it though. Another question that follows on from this info, however, is how linear is the change in viscosity behaviour between the measured 40 deg and 100 deg points? And what's all this about oil pump failures? How would you tell if your oil pump is dodgy - I presume you have to check the oil pressures it's generating? How much is an oil pump for a VR, and is it tricky to fit, out of curiosity? Quote Share this post Link to post Share on other sites
RW1 0 Posted June 2, 2005 OEM recommendation Above -15 VW 501.01 SAE 15W-40 From -20 to 15 VW 501.01 SAE 10W-40 British summers +30'C tops, winters mostly -5' bottom (unless you're really "up north") => 15w40 Dr_mat, oil pump failures aren't a regular thing with the C so don't hang on this one. Just when some have gone surprisingly early. Not the pump design as that's fairly standard. Simple check if you have a gauge at 90'C oil temp 1.5 to 2 bar (23 - 30 psi) at idle, 3.5 to 4 bar (52 to 60 psi) at 3,000 rpm using 15w40 oil grade. Price? Job - quite straight forward, drop the sump - loads of little bolts, 2 bolts on pump, loads of oil around - little messy, less than an hour to do, one sump gasket besides the pump needed. Points to note, make sure the bottom face of the engine block is really clean so that the sump gasket sits perfectly otherwise seepage occurs and tighten the sump bolts from the C's centre line outwards so it doesn't "bow" in the middle and leak. Quote Share this post Link to post Share on other sites
Christoph 0 Posted June 2, 2005 According to this article "Always use a multi grade with the narrowest span of viscosity that is appropriate for the temperatures you are going to encounter." "fewer polymers are better" "10W-40 and 5W-30 require a lot of polymers (synthetics excluded) to achieve that range" "AMSOIL can formulate their 10W-30 and 15W-40 with no viscosity index improvers but uses some in the 10W-40 and 5W-30. Mobil 1 uses no viscosity improvers in their 5W-30, and I assume the new 10W-30." So once you've found the right multigrade, it also helps to know how the oil is made. Chris 94 VR6 Quote Share this post Link to post Share on other sites
oilman 0 Posted June 2, 2005 This is related to shear stability and the polymers concerned are VI Improvers. Explaining the importance of shear stability in laymens terms is difficult but I'll try. Viscosity Index Improvers. An oils viscosity will decrease as the engine temperature rises. Viscosity Index Improvers are added to reduce this thinning. They are a key addative in the production of multigrade oils. VI Improvers are heat sensitive long chain, high molecular weight polymers that increase the relative viscosity of the oil at high temperatures. They work like springs, coiled at low temperatures and uncoiling at high temperatures. This makes the molecules larger (at high temps) which increases internal resistance within the thinning oil. They in effect "fight back" against the viscosity loss in the oil. "Shearing" The long chain molecules in VI Improvers are prone to "shearing" with use which reduces their ability to prevent the oil from losing viscosity. This "shearing" occurs when shear stress ruptures the long chain molecules and converts them to shorter, lower weight molecules. The shorter, lower weight molecules offer less resistance to flow and their ability to maintain viscosity is reduced. This shearing not only reduces the viscosity of the oil but can cause piston ring sticking (due to deposits), increased oil consumption and increased engine wear. Like basestock quality, VI Improvers also vary in quality. The best quality ones are normally found in synthetic oils (Group IV - PAO / Group V - Esters) and it is important to understand that the less of these in the oil the better the oil will stay in grade. Which oils require more VI Improvers? There are two scenarios where large amounts of these polymers are required as a rule. Firstly in "wide viscosity" multigrades. By this I mean that the difference between the lower "W" number and the higher number is large for example 5w-50 (diff 45) and 10w-60 (diff 50) are what is termed as "wide viscosity" oils. Narrow viscosity oils like 0w-30 (diff 30) or 5w-40 (diff 35) require far less VI Improvers and therefore are less prone to "shearing". Secondly, mineral and hydrocracked (petroleum synthetic oils) require more VI Improvers than proper PAO/Ester (Group IV or V) synthetic oils as they are less thermally stable to begin with and this is due to the non-uniform molecules in petroleum oils as opposed to the uniformity of synthetics built in laboratories by chemists. It is a fact that some synthetics require little or no VI Improvers to work as a multigrade due to their superior thermal stability. Cheers Guy Quote Share this post Link to post Share on other sites
stevemac 0 Posted June 23, 2005 Yawn, yawn .. :roll: This has been discussed so many times. VW main dealers (including the one that I used to work for) use/used Synta Silver in all Corrados - that's good enough for me. Quote Share this post Link to post Share on other sites
