Capt. Mike
Moderator
Reposted from archives
Responding to a question on whether synthetics were worth the extra money . . .
10/3/98 (9:44 PM)
OK, my best source on oils, a now-retired Texaco Lubricants Division trouble-shooting specialist, says synthetics aren't worth the extra money in normal auto use, regular climates. I'm sure there are some improvements, and I no longer condemn "fake oil" as being mostly marketing hype. It has its uses, but again, limited in everyday car applications. As he said, "Hell, we don’t recommend it and we make it!"
First, oil's limiting factor is the additive package. That includes the viscosity improvers to get thinner oil to protect like thicker base oil, and cling characteristics to prevent it from draining off parts completely (start-up protection). The additive packages for both oils are pretty much the same, so their limits (miles between changes) are about the same. Notice VW has not given a green light for extending oil changes because of synthetics. And if you look on the label, you'll still see the same API specifications on synthetics as regular.
Three combustion by-products unrelated to oil type are acidity, moisture/condensation and particulates. Acidity is the big limiting factor. The additives can only neutralize so much. Particulates are dependent on filtering and the detergent additive's ability to keep it suspended until it reaches the filter. Although most engines operate much hotter now, not all run hot enough to get the oil past 212F. Not usually a problem with VW's, but my Cummins diesel rarely breaks 180F. Same is true in short run driving. Moisture won't boil off, so again I need the additive help.
This is why, especially in the "heavy duty" area 98% of all Westies fall into, that the 3,000 mile oil changes are necessary. Push that, and additives may diminish or fail. The engine won't stop on you, but you're adding varnishing (particularly in Pennsylvania and mid-east crudes that have a high paraffin content); possibility of acid etching; increasing filter load (maybe to the point of tripping the bypass); and other engine wear factors. Synthetics’ advantages are, as a premium priced oil, they will have the best of additive packages, though I’m sure all premium petroleum oils do, too. Quality theoretically should be slightly more consistent as the manufactured base isn't subject to the variations of crudes. Synthetics seems to have an inherent "cling" advantage. They can definitely provide better protection at overheated temperatures (the usual infomercial style ad). Because most synthetics are thinner (base viscosity) oils that get their extended viscosity protection, the upper & lower ends, by their better cling and overheat protection, they are superior in real cold weather.
Synthetics have been around for years. They were used in the airplane and Arctic equipment before the Big One, but never marketed for cars because the costs versus gains weren't (aren't) there. Until the yuppies started throwing extra money at their Bimmers as a status symbol, nobody bought it. Now, how much they spend on a service seems to be a status symbol!
Notice, very few manufacturer's use synthetics for factory fill. Bear in mind that the worst 300 miles of an engine's life are its first 300. If synthetics reduced warranty repairs, you bet they would use them; the cost at factory quantity prices is negligible in the overall warranty cycle of a new car. Porsche is the only manufacturer I know that uses synthetics in new cars, and Mobil 1 pumps millions into their race budget. When Shell was sponsor, there were "Shell Factory Fill" stickers on new cars (my '69 has one); later you saw Sunoco (Penske Racing), Gulf Oil (Gulf-Weyer 917s) or whoever would drop the big sponsor bucks getting promoted as Porsche's oil. $30 difference on a $60K car isn't a factor if it gets sponsorship. Conversely, factory-fill status on a Porsche will sell a lot more quarts than factory fill on a Pinto. Browse the decals on your favorite NASCAR or Indy racer. Where money is absolutely no object for oil, what do they use? I bet there aren't half-dozen synthetics in the field. The factory race team I worked with for a year (four 24-hr. Daytona class wins in a row) did not use synthetic in either regular or rotary engines. Engine man (team owner retired) still doesn't, and his engines dominate several boat racing classes and hold a host of world records.
I think the big reason synthetics are now getting play and manufacturers' blessings is the tendency to go to thinner oils for fuel economy. Hundredths of a mpg, not important to us, are BIG numbers to manufacturers trying to get CAFE (corporate average fuel economy) numbers up. With big vans & SUVs sucking the fuel down, they face $millions in fines. A 5W-30 will get better mpg than 10W40!
One area where I would tentatively recommend synthetics is in turbocharged engines. The turbo operates at exhaust temperature. My Cummins exhaust reaches 5-600F, but I hear 1,000F is common on big rigs and high performance gas engines. When you stop the engine, the lube supply stops too. The oil left in the turbo can cook-off. There, synthetics have a distinct advantage. My Cummins manual says to allow the engine to idle 3-5 minutes before shutting down. I have a pyrometer gauge, so I idle until it drops to 300F before I shut off. Most turbo cars don't have gauges, and most drivers don't have the patience to let them idle down, so a synthetic might be a good idea for the impatient. I use Shell Rotella-T and do idle down, so won't switch. At three gallons every 3,000 miles that would add up!
I do intend to use synthetic manual transmission oil in my '96 Dodge 4x4 truck. The manual specifies it and I've got a 100,000 mile warranty. Although they don't require any changes, I've never believed in "lifetime" fluids, and will change every 36K. At the first change I bought factory fluid (Dodge list, $19.95 per quart!!!). Guess what it is? 75W/85 GL-4! Not even GL-5, which superseded Gl-4 over 20 years ago by adding an impact additive. The reason for synthetic is cling characteristics. There's apparently a bearing back in the case that doesn't get lube right away at start. One dealer chain I know uses Mobil 1 anyway, though Mobile engineers say their transmission oil doesn't meet the specs (European Castrol Syn-Torq LT is the OEM supplier) because of a patent protected additive package, not because of any inherent superiority. No OE fluid = no warranty. So I'll use it through 100K, then change to something a little more reasonable, cost-wise. I expect to stay with synthetic because of that bearing, just not Dodge brand.
Dana, the big axle manufacturers, makes the axles for the big Dodge trucks and most 18 wheelers. They use standard 90W GL-5, but recommend 12K changes if towing. Dodge suggests "considering synthetics" for HD towing use. Still, no factory fill, and they're only a quart each. The Dana limited slips do require an additional additive, Kendall P/N 505-7478. Most limited slips, VW included, don't require the additive, but GL-5 does contain the necessary impact additive for most users.
One disadvantage of synthetics, that VWs are particularly prone to, is leaks. VWs, with metal-to-metal case seams, will leak to one degree or another. Mostly the other; "Sieve"; comes to mind after a while. Being generally thinner, synthetics will find every little leak and turn them into big ones. Even gasketed seals seem to leak more. I've a number of friends that use my shop or I help, and I've seen them change to synthetics only to incur leaks at an alarming rate. Not scientific research, to be sure, but in a couple of instances, the leaks returned to normal after switching back.
One thing I would not do is mix oils. Oil additive packages can do erratic things if mixed. With a mix, you may not get enough of one additive or another to give minimum protection. Additive packages are not necessarily cumulative, and could interact. There are semi-synthetic factory blends, but I strongly advise against home brews. The two oils you mix may have very different bases, using different additives to achieve similar protection. Again, the additives in one may react on the other's different base detrimentally. Although VW says mixing viscosity is OK, I don't even recommend mixing brands of the same type & weight oil, for the same reasons. I'm sure half a quart of Castrol in a Shell filled engine won't do harm, but my lube engineer cautions minor "topping off" is about the only allowable mixing.
Note that every manufacturer, VW included, recommend "more frequent oil changes in heavy service." When you investigate heavy service, you find it includes everything we do with a Westy. Around town driving, high speed, mountain, cold weather, heavy loads, towing, dirty or dusty conditions. Come to think of it, that's ALL my driving! And I'll wager most of yours. So the 7,500 mile changes in the Westy maintenance book never happen. Stick to the 3,000 miles, with filter!
To the original questioner from Chicago: I really think 10W-30 or 10W-40 will serve well in Chicago. It's rated down below 0F and brief dips below that shouldn't hurt, especially with a gentle start up. A steady diet of 5W-30 worries me in that its upper recommended limit is only about 20F. And VW cautions against high speed runs or extended use too far out of range on 5W-30. 10W-30 has an upper limit of about 60F, so I don't think I'd like that in the summer where average temps are in the 70s or 80s. Likewise, 20W-50 is great for NC or further south summers and even the worst couple months of Chicago summers. I've used it myself in the past but I now have a mixed fleet so use Shell Rotella-T 15W-40 in everything. I'd probably want a 20W-50 in the desert, extreme south and southwest. It basically boils down to READ your owner's manual and use an oil within the operating ranges of your area.
While on the subject of oils, I will mention additives only briefly: Don't! VW does not recommend additives and for good reason. Any additive is liable to upset the very delicate balance of base weight and additives in the regular oil. STP is nothing more than a thick, viscosity improver. Thicker oil means less consumption; also less protection at start up, and putting your oil completely outside intended range. Use the right weight oil instead of trying to thicken it up.
A real Madison Ave. job was Slick-50 with Teflon. "Coats the metal." Yep, and also every pipe, passage and pump part, too. I don't care what they say, you can't permanently coat the inside of a thousand plus degree engine cylinder, with razor sharp scraping piston rings. So when you repeat the treatment, (which they recommend even though it's permanent!?!), you add another coat to the oil passages and non-wear parts. Pretty soon it builds up enough to reduce or block passage. Heavier build-ups could break free and clog filters or add particulates to the oil.
Another super-additive on the late-night infomercial channels lately is Prolong. Consumer reports recently ran a test of this product (Oct 98). Both treated and untreated engines failed within 13 minutes and 5 miles, both at the same time. The FTC has recently cracked down on other additive makers' false claims, and have been advised about Prolong.
Most oils contain excellent detergents. Additives to "clean" your engine, remove sludge, etc., aren't necessary. Even a gummed up engine will respond some to several frequent changes of a premium oil. And, unlike additives, oil holds the dirt in suspension until it reaches the filter. Additives would only break it loose, perhaps in chunks bigger than you want.
The net result is that oil and car companies, with billion dollar research budgets, are producing products that do all you want out of your oil at reasonable prices. Quit wasting your money on magic cures in a bottle and start spending it on quality oil, filters and regular changes.
Responding to a question on whether synthetics were worth the extra money . . .
10/3/98 (9:44 PM)
OK, my best source on oils, a now-retired Texaco Lubricants Division trouble-shooting specialist, says synthetics aren't worth the extra money in normal auto use, regular climates. I'm sure there are some improvements, and I no longer condemn "fake oil" as being mostly marketing hype. It has its uses, but again, limited in everyday car applications. As he said, "Hell, we don’t recommend it and we make it!"
First, oil's limiting factor is the additive package. That includes the viscosity improvers to get thinner oil to protect like thicker base oil, and cling characteristics to prevent it from draining off parts completely (start-up protection). The additive packages for both oils are pretty much the same, so their limits (miles between changes) are about the same. Notice VW has not given a green light for extending oil changes because of synthetics. And if you look on the label, you'll still see the same API specifications on synthetics as regular.
Three combustion by-products unrelated to oil type are acidity, moisture/condensation and particulates. Acidity is the big limiting factor. The additives can only neutralize so much. Particulates are dependent on filtering and the detergent additive's ability to keep it suspended until it reaches the filter. Although most engines operate much hotter now, not all run hot enough to get the oil past 212F. Not usually a problem with VW's, but my Cummins diesel rarely breaks 180F. Same is true in short run driving. Moisture won't boil off, so again I need the additive help.
This is why, especially in the "heavy duty" area 98% of all Westies fall into, that the 3,000 mile oil changes are necessary. Push that, and additives may diminish or fail. The engine won't stop on you, but you're adding varnishing (particularly in Pennsylvania and mid-east crudes that have a high paraffin content); possibility of acid etching; increasing filter load (maybe to the point of tripping the bypass); and other engine wear factors. Synthetics’ advantages are, as a premium priced oil, they will have the best of additive packages, though I’m sure all premium petroleum oils do, too. Quality theoretically should be slightly more consistent as the manufactured base isn't subject to the variations of crudes. Synthetics seems to have an inherent "cling" advantage. They can definitely provide better protection at overheated temperatures (the usual infomercial style ad). Because most synthetics are thinner (base viscosity) oils that get their extended viscosity protection, the upper & lower ends, by their better cling and overheat protection, they are superior in real cold weather.
Synthetics have been around for years. They were used in the airplane and Arctic equipment before the Big One, but never marketed for cars because the costs versus gains weren't (aren't) there. Until the yuppies started throwing extra money at their Bimmers as a status symbol, nobody bought it. Now, how much they spend on a service seems to be a status symbol!
Notice, very few manufacturer's use synthetics for factory fill. Bear in mind that the worst 300 miles of an engine's life are its first 300. If synthetics reduced warranty repairs, you bet they would use them; the cost at factory quantity prices is negligible in the overall warranty cycle of a new car. Porsche is the only manufacturer I know that uses synthetics in new cars, and Mobil 1 pumps millions into their race budget. When Shell was sponsor, there were "Shell Factory Fill" stickers on new cars (my '69 has one); later you saw Sunoco (Penske Racing), Gulf Oil (Gulf-Weyer 917s) or whoever would drop the big sponsor bucks getting promoted as Porsche's oil. $30 difference on a $60K car isn't a factor if it gets sponsorship. Conversely, factory-fill status on a Porsche will sell a lot more quarts than factory fill on a Pinto. Browse the decals on your favorite NASCAR or Indy racer. Where money is absolutely no object for oil, what do they use? I bet there aren't half-dozen synthetics in the field. The factory race team I worked with for a year (four 24-hr. Daytona class wins in a row) did not use synthetic in either regular or rotary engines. Engine man (team owner retired) still doesn't, and his engines dominate several boat racing classes and hold a host of world records.
I think the big reason synthetics are now getting play and manufacturers' blessings is the tendency to go to thinner oils for fuel economy. Hundredths of a mpg, not important to us, are BIG numbers to manufacturers trying to get CAFE (corporate average fuel economy) numbers up. With big vans & SUVs sucking the fuel down, they face $millions in fines. A 5W-30 will get better mpg than 10W40!
One area where I would tentatively recommend synthetics is in turbocharged engines. The turbo operates at exhaust temperature. My Cummins exhaust reaches 5-600F, but I hear 1,000F is common on big rigs and high performance gas engines. When you stop the engine, the lube supply stops too. The oil left in the turbo can cook-off. There, synthetics have a distinct advantage. My Cummins manual says to allow the engine to idle 3-5 minutes before shutting down. I have a pyrometer gauge, so I idle until it drops to 300F before I shut off. Most turbo cars don't have gauges, and most drivers don't have the patience to let them idle down, so a synthetic might be a good idea for the impatient. I use Shell Rotella-T and do idle down, so won't switch. At three gallons every 3,000 miles that would add up!
I do intend to use synthetic manual transmission oil in my '96 Dodge 4x4 truck. The manual specifies it and I've got a 100,000 mile warranty. Although they don't require any changes, I've never believed in "lifetime" fluids, and will change every 36K. At the first change I bought factory fluid (Dodge list, $19.95 per quart!!!). Guess what it is? 75W/85 GL-4! Not even GL-5, which superseded Gl-4 over 20 years ago by adding an impact additive. The reason for synthetic is cling characteristics. There's apparently a bearing back in the case that doesn't get lube right away at start. One dealer chain I know uses Mobil 1 anyway, though Mobile engineers say their transmission oil doesn't meet the specs (European Castrol Syn-Torq LT is the OEM supplier) because of a patent protected additive package, not because of any inherent superiority. No OE fluid = no warranty. So I'll use it through 100K, then change to something a little more reasonable, cost-wise. I expect to stay with synthetic because of that bearing, just not Dodge brand.
Dana, the big axle manufacturers, makes the axles for the big Dodge trucks and most 18 wheelers. They use standard 90W GL-5, but recommend 12K changes if towing. Dodge suggests "considering synthetics" for HD towing use. Still, no factory fill, and they're only a quart each. The Dana limited slips do require an additional additive, Kendall P/N 505-7478. Most limited slips, VW included, don't require the additive, but GL-5 does contain the necessary impact additive for most users.
One disadvantage of synthetics, that VWs are particularly prone to, is leaks. VWs, with metal-to-metal case seams, will leak to one degree or another. Mostly the other; "Sieve"; comes to mind after a while. Being generally thinner, synthetics will find every little leak and turn them into big ones. Even gasketed seals seem to leak more. I've a number of friends that use my shop or I help, and I've seen them change to synthetics only to incur leaks at an alarming rate. Not scientific research, to be sure, but in a couple of instances, the leaks returned to normal after switching back.
One thing I would not do is mix oils. Oil additive packages can do erratic things if mixed. With a mix, you may not get enough of one additive or another to give minimum protection. Additive packages are not necessarily cumulative, and could interact. There are semi-synthetic factory blends, but I strongly advise against home brews. The two oils you mix may have very different bases, using different additives to achieve similar protection. Again, the additives in one may react on the other's different base detrimentally. Although VW says mixing viscosity is OK, I don't even recommend mixing brands of the same type & weight oil, for the same reasons. I'm sure half a quart of Castrol in a Shell filled engine won't do harm, but my lube engineer cautions minor "topping off" is about the only allowable mixing.
Note that every manufacturer, VW included, recommend "more frequent oil changes in heavy service." When you investigate heavy service, you find it includes everything we do with a Westy. Around town driving, high speed, mountain, cold weather, heavy loads, towing, dirty or dusty conditions. Come to think of it, that's ALL my driving! And I'll wager most of yours. So the 7,500 mile changes in the Westy maintenance book never happen. Stick to the 3,000 miles, with filter!
To the original questioner from Chicago: I really think 10W-30 or 10W-40 will serve well in Chicago. It's rated down below 0F and brief dips below that shouldn't hurt, especially with a gentle start up. A steady diet of 5W-30 worries me in that its upper recommended limit is only about 20F. And VW cautions against high speed runs or extended use too far out of range on 5W-30. 10W-30 has an upper limit of about 60F, so I don't think I'd like that in the summer where average temps are in the 70s or 80s. Likewise, 20W-50 is great for NC or further south summers and even the worst couple months of Chicago summers. I've used it myself in the past but I now have a mixed fleet so use Shell Rotella-T 15W-40 in everything. I'd probably want a 20W-50 in the desert, extreme south and southwest. It basically boils down to READ your owner's manual and use an oil within the operating ranges of your area.
While on the subject of oils, I will mention additives only briefly: Don't! VW does not recommend additives and for good reason. Any additive is liable to upset the very delicate balance of base weight and additives in the regular oil. STP is nothing more than a thick, viscosity improver. Thicker oil means less consumption; also less protection at start up, and putting your oil completely outside intended range. Use the right weight oil instead of trying to thicken it up.
A real Madison Ave. job was Slick-50 with Teflon. "Coats the metal." Yep, and also every pipe, passage and pump part, too. I don't care what they say, you can't permanently coat the inside of a thousand plus degree engine cylinder, with razor sharp scraping piston rings. So when you repeat the treatment, (which they recommend even though it's permanent!?!), you add another coat to the oil passages and non-wear parts. Pretty soon it builds up enough to reduce or block passage. Heavier build-ups could break free and clog filters or add particulates to the oil.
Another super-additive on the late-night infomercial channels lately is Prolong. Consumer reports recently ran a test of this product (Oct 98). Both treated and untreated engines failed within 13 minutes and 5 miles, both at the same time. The FTC has recently cracked down on other additive makers' false claims, and have been advised about Prolong.
Most oils contain excellent detergents. Additives to "clean" your engine, remove sludge, etc., aren't necessary. Even a gummed up engine will respond some to several frequent changes of a premium oil. And, unlike additives, oil holds the dirt in suspension until it reaches the filter. Additives would only break it loose, perhaps in chunks bigger than you want.
The net result is that oil and car companies, with billion dollar research budgets, are producing products that do all you want out of your oil at reasonable prices. Quit wasting your money on magic cures in a bottle and start spending it on quality oil, filters and regular changes.
Answered above page 1, 4/10/02, post #8.