17 k is ideal for once a year oil changes using amsoil oil and air filters.I also use the by-pass filter and have been changing oil once a year at about 14k miles.If you are leary of the one year then take oil samples to reassure you.it's almost defeating the purpose of synthetic oil not to go the full year.
Been using Mobil 1 for years... I typically go 6K miles between oil changes, even on my winter-beater Skyhawk w/1.8 4-cyl Turbo. I'm more concerned about the filter life than the oil. For a little more than $20, I can get 5 qts. of Mobil-1 oil and the Mobil-1 filter at Autozone. They run that special at least twice a year. $40/year is a small price to pay vs. any oil-related engine problem.
That's why I use the by-pass filter plus the amsoil brand filter,I know the amsoil spin-on filters to a finer degree than the mobil one filter.the leading filter makers seem to stress percentages and housing strength and never say how small a particle it will filter,I don't care if my oil is being filtered 10 times a minute if the filter is not stopping the smaller particles.the by-pass filters to below one micron this virtually eliminates wear caused by solid particles in the oil,plus you get to use an extra qt. or 2 depending on filter size.
Good point, Markbuck. I suppose there will always be room for discussion about filter porosity but but, because motor oil is also contaminated by non-particulate products of combustion, it is surely good economics to change it at least as often as recommended by the engine manufacturer.
Let me do some research on your point,it is a good one,I know I have taken oil samples on some engines using amsoil and have gotten good readings even at hi mileage.I think alot of the acid and dilution would depend on location,time of year and driving habits.
oilcan....Do you have a webset of testing of Amsoil ( by a independent company ) we know from your past posting that,,,,you just happen to sell the stuff,,,so I am questioning your motive to post numerous posting saying about how great it is...
I know amsoil has thier own lab for sample testing I have also used the oil sampling that the catapillar dealers sell. My motive is that I think it is the best product out there,I am a dealer mainly to get the product if I sell to individuals I sell for dealers cost. I'm not sure about redline but amsoil makes the only syn. atf fluid so that eliminates other brands,they make a "oiled foam" air filter that is much cheaper than k&n.they make the bypass filter,(there are a few other brands out there but not the exact same kind)I think these help when you have a 4 cyl.holding 4.5 qt. and using this gives you an extra qt.I think mobil one is the next best syn out there but I think amsoil has a better array of products to compliment the oil.I think the only way to conduct long term tests would be to buy 2 of the same car one with syn. one without and give them to one driver and tell him to switch cars every day till you get a few hundred thousand and then take the engines apart and compare.
I know one thing for sure ,,I always thought that a remote or duel remote filter seems to make sense,,for the ease of access to the filter,,extra oil capacity,,,,extra filtration...and it's not rocket science to hookup...
I've been using a comapany called Analysts Inc for my samples over the past nine years. I agree with above on extended intervals, the analysis for wear metals, chemicals etc. shows almost no diff between 3,000 mile changes and 10,000 on my cars. Synthetics oils simply work better and last much longer. I never believed Amsoil claims until now, after 9 years I go about 10,000 betwenn changes and analysis comes back that the oil is still good. Silicon particles, which is an absolute measure does not depend on mileage, if over the limit the analysis flags it but at 10,000 it has been okay, under 30 ppm (parts per million)
I have been using Mobil 1 on one vehicle for app 75,000 miles with 15,000 mile intervals or app 5 changes. It has been simply flawless and a no brainer. I especially like not having to do 25-5= (20) oil changes less. With a total of 4 vehicles it is simply wonderful not to have to do the oil changes as many times.
I use Amsoil 10W30 with a Hastings filter on a bypass system. Climate ranges from around 0 to 100 deg F, so the engine and oil get a real workout. Engine rpm is up a little at idle, but runs clean after 3K mi. Did better (cleaner) than the dino that was in it.
My second of two bits is that you get what you pay for. There are so many products in the market that you have to really do your homework if you are either that worried about it, or you really take engine science seriously.
Hi packman2, remember me?
Hey oilcan2, is it true that some synths are biodgradeable?
Yes I do have my doubts as to the reason for only a couple of you mentioning Amsoil so many times,,,I even saw one of you gentlemen mention it in the Automatic transmission flushing,,,,Since one of you said it is better than Mobil 1....log me on to the independent website to back that up,.....
Not for the price. I realize the some of you are hot after Amsoil and Mobile 1 oils,but honestly,unless you start out at day one with that specific oil, the benefits are going to be limited.A good quality oil is the best and most economical oil for your vehicle,regular oil changes and preventive maintenace and your engine will be happy. Sythetics are fine oils,but the claims made about them are a bit exagerated.
I don't think any of the syn oils are biodegradeble,opatience,amsoil calls one of their filters a dual remote,it is a reg.filter and the one used in the by-pass mode,the first by-pass filter they made was the seperate one I mentioned before,I have never had one clog up on me so I assume it is working as long as oil passes thru it.also why is the syn.going to have dif.benifits if we use it right away or wait a few thousand miles.I've read alot of posts about what the manufacturers say,for years they had nothing good to say about syn oils,in the past few years some of the higher priced big three cars are being shipped with syn oil.
My wife has a new Chevy Lumina,it has never had synthetic oil in it. On the fleets I work on, none of the vehicles Dodge,Ford and GM came with sythetic oils. In fact,the only that I work on that have any synthetic oils in them are Freightliners,which use a sythetic in the differentials and we have lost 7 differentials in 1 year and they constantly leak.
#174 MB E320 (that I know of) comes with synthetic oil, and the first oil change is due @10k to 15k.
Seems like when the manufacturer/dealer pays the tab for the maint and oil changes they want to extend the intervals (and can for the superior synthetic oils).
I have been on 15k change intervals and in effect do 4 less oil changes, (80% less or 5x more [using the 3k interval}) depending on your point of view. I like using less oil products, saving time and money.
I agree, I have 5 cars to maintain and two are on once a year change schedules and one is at 7,500, one at 12,000 and one at 5,000 (twin turbo) all using synthetic. Differences based upon type of driving and oil analysis. However, not having to change as often eliminates a huge hassle with multiple cars. After 9 years of synthetics I swear by them, well, swear by Mobil 1 and Amsoil only, all others are imitations!
I have a '96 MB E320. Its service manual calls for 7500 mile oil changes. Since yours is still under warranty I assume that you have a newer one, and that MB has extended the oil change intervals.
I personally change even below 7500 miles, but this is only because of two reasons:
a) It is so very easy to change oil on an MB.
b) It might be my own superstition, but I would be concerned about particles after 15K miles.
All this probably will make little of a difference in the end, but engine oil seems to be such an emotional subject, that I'd rather stay in my own comfort zone.
I've been to borth the Amsoil and the Redline sites. Although I didn't count every item on my fingers, It seemed to me that Redlines' lubricant product line was every bit (or more) as extensive as Amsoil. I have been a user of their MTL manual tranny lubricant for years, and know that they also carry an extensive line of auto tranny lubricants.
#176 Yes, Y2k model yr. Less than 1k on the clock, so not even close to the oil change interval. Yes the old habit of 3k oil changes dies very very hard.
I have always used Mobil 1 and changed at 5K intervals, but am now switching over to Amsoil on my truck and going to 1 year changes, or 10K-15K depending on analysis.
A good reason for increasing change intervals is the environmental impact as well as the cost savings. This is the reason Europe is going to 9K+ intervals regardless of vehicle.
I have read that most (if not all) new cars in Germany are filled with synthetic, and you would have a hard time finding petro-based oils there.
In response to markbuck's question on acids and such, high quality oils contain corrosion inhibitors, oxidation inhibitors, and emulsion modifiers to protect against the acids from combustion. These additives are designed to coincide with the recommended change intervals. However, you should always have your oil analyzed at least once a year to determine if there are problems within the engine that increase combustion by-products from normal levels.
I am a little worried with my new car. My 2000 BMW Z3 has synthetic oil - with a first recommended oil change at 15,000 miles/1 year. Seems way too long to me. Any suggestions/comments?
If you can change your oil for less than $13, you must be using very cheap oil and filter. This would just overstate the need for analysis as there would likely be more particulates and corrosives in the oil regardless of duration.
To spend $15-20 a year on analysis is just a given, no matter how you change your oil.
Given your situation with low yrly miles and stop and go in a high temp and humidity climate (I lived in Miami, Fl for a number of yrs) I wouldn't have any hesitation at using/switching to synthetic and going to a yrly oil change as you plan. It is a good idea to take it on a longer trip say once a month or more, if you are a low milege user. Of course, the party line is that you should not exceed the warranty reccommendation.
Actually one of the first cars which came with factory fill were the Shelby 1986 Omni GLHS Turbos, Shelby subsequently used them in all his cars which came out of Whittier CA. THey used Mobil 1.
Shelby was smart enough to know that synthetics make a big difference in the longetivity of the engines and turbos.
I use Amaoil in all my cars and drain them every 2 years or roughly 20K miles. I also use the Amsoil by pass filter and their oil wetted foam air filters.
Past experience via oil analysis indicated no problems and on one engine, when I replaces a head gasket at 110K miles, the engine was perfectly clean, hone marks still visable, no ridge or taper in the cylinder bores etc.
I wouldnt use anything else. Amazing how all the other comapnies are jumping on board, now that they see a niche market. Too bad, I'll stick with the Amsoil.
Yes, acutually there are a few ways to tell about your engine. Oil analysis is the best way, but the cost of doing that is perceived as not being cost effective. Another is to remove your valve covers, oil pan etc etc for a visual inspection. Again most folks can't or won't do this for a host of reasons.
While the conventional oil is better than it ever has been (meeting much higher technical standards), I agree with you that the synthetic is the superior lubricant. And on a interesting level the marketing for conventional oil seems to be doing better, judging by the numbers and %'s that still stay with it.
Yes, it has the same argument, lasts two-three times longer, protects better, flows better at much lower temps (eliminates that sluggish start up in cold weather when you shift into gear for the first time) and a higher overall heat range. Anywhere from $4-$6.50/quart
Have used the amsoil trans fluid in a colony park sw for 8 years,change about every 3.I can drain my torque converter and get 100% out of the trans.On cars that cannot I would take the oil to one of those shops that has the machine to flush the trans and have them install the fluid. The car has 235,000 miles and has never had trans problems.
Amsoil may be a good oil,but at the cost is not that great a benefit.If you like it,that's great.Go ahead and use it,but trying to sell other people and saying it will extend you oil change intervals by so much isn't cool. I just had to work on a guys engine that he was told by and salesman that he could go 15,000 miles between oil changes.At 95,000 miles,he had bearing failure,but that wasn't the oils fault,right? Now the guy is looking at a major job.That expensive oil saved him alot huh?
This is the syn. oil topic and there are only a few companies making syn. trans fluid,so maybe thats why amsoil was recommended.Your buddies engine would have been a perfect case for oil analysis,if the sample came back bad then you could really blame the oil,if the oil tested ok then why did the bearings burn up,did he put the oil in a car with 80,000 miles on conventional oil and expect the worn bearings never to wear out?what oil was it,did he change the filter during this time? The cost factor is different for every individual for me it is worth it,every car is different,and has different wear and tear,generally speaking you can get at least twice the use out of syn. trans fluid vs. non-syn fluid. P.S.This topic is getting like the ZAINO and non zaino topics.
I've been using Mobile 1 full synthetic for many years, and I've never had a single enigine problem. Until someone can show me proof that Amzoil offers better protection, I'm sticking with Mobile 1.
FWIW, here is a comparison test I've seen between Mobil 1 and Amsoil. The test is based on a Falex pin and vee test machine. Amsoil produced slightly better results (lower teeth is better) than Mobil-1 5w-30, while the heavier Mobil-1 failed the test.
Falex: Amsoil 15w-40 passed at 9 teeth Mobil-1 5w-30 passed at 12 teeth Mobil-1 15w-50 failed
Also, Amsoil showed better scores in oxidation tests.
I find it interesting that Mobil-1 makes no claims about wear testing or extended intervals on their website as explained here is an excerpt from "The Motor Oil Bible", an article obtained from another Amsoil website (http://www.bestsyntheticoil.com/amsoil/index.shtml):
"In my opinion Mobil 1 oils are most likely good for 10,000 to 15,000 miles, but the company does not make that recommendation. I have known of many people who do very well running Mobil 1 for these intervals, but it has not been designed specifically for extended drain use. Moreover, the company probably would not back you if you had any mechanical problems resulting from such extended drain use, since they only recommend 'manufacturer recommended change intervals'".
Now, don't get me wrong. I'm not saying Mobil-1 is a bad oil. I think it is an extremely good oil to use, and I have been using it for years. However, Amsoil appears to be better and backs up their claims with testing, technical properties, and warranties.
What cost comparison are you referring to with Amsoil? My calculations are as follows:
Conventional oil changes over 12K miles: 20 quarts x 2.25/qt. = $45 4 filters x 5.00/ea. = $20 Total cost = $65
Extended drain change at 12K miles: 5 quarts x $7.95/qt = $39.75 1 filter x $10 = $10 Total cost = $49.75
So, not only do I save over $15 (which BTW pays for an analysis), I perform 3 less oil changes which contributes to less oil in the refining plants, and less to recycle which is better for the earth. Makes perfect sense to me.
BTW, this is from the Amsoil website: "AMSOIL products clearly offer better wear protection than competitive synthetics and much better protection than conventional oils. Engines can fail due to mechanical problems even when using AMSOIL. AMSOIL Motor Oils, however, in over twenty-five years have never caused an engine failure. If you ever hear someone say AMSOIL caused their engine, bearings, pistons, etc. to fail, they are wrong."
I run premium products in my tranny, transfer case, diffs,.... As I only change em once in a blue moon and the pain to change them is worth the expense.
Still not convinced that premium synthetics are worth it for motor oil
I'm interested in any arguments for conventional oil at 3K drains. What facts can you present to indicate that this is the better choice? I am not looking to make decisions for others, but am merely trying to decide this debate for my own personal choice. If there is some advantages to conventionals at 3K, I would like to know. Thanks for any insights.
I have a '98 Hyundai Elantra GLS, 1.8L eng. w/ 36K on it. 3.5k after the last change, the oil was very ready to be changed. Pretty dirty after that long. According to the shop I last took it to for an oil change, they used Penzoil, with a Hyundai brand filter. Changed the oil and added synth w/ Fram filter myself. We'll see how it goes.
I also owned an '89 Volkswagen Fox about 5 yrs ago. Used all conventional oil (Mobil) with off-the-shelf filters and it ran clean, even up to 5,000 mi. between one of the changes. The only reason I still don't own it is because it got wrecked. Maybe it was the condition of the engine. I've read few complaints about VW engines!
Whoever noted that they use Fram filters should look at the comparisons etc. Frams are junk as noted by their price. Get a decent filter, Pure One, Mobil 1 or Amsoil. As to Mobil 1 oil, great stuff. I use Amsoil but in speaking to the lead chemist at Amsoil one day he confirmed that if he did not use Amsoil ( or probably work for them) he would use Mobil 1. These are really the only two, the others (new to the field) are wannabees just jumping on the synthetic wagon as it rolls on.
I never said that it was the oils fault for the bearing failure,but it evidently didn't help.Look,you can quote any manufacturer and believe everything you read,that is fine.No matter what anyone says,there is no substitute for regular maintenance.I deal with several different oils,oil analysis and maintenance programs with fleets,and have done so for years. My stance on it,is that if your engine is not in good condition when you start using a synthetic,alot of times,they will leak. From talking to a manufacturer engineer and a CATERPILLAR analyst,I use a premium grade 15w40 fleet oil.I have a 70 chev 4x4 with 330,000 miles on the engine,oil changed every 5,000 miles(I have no warranty to worry about),same brand and weight oil since the engine was new.I always love when they say that the oil didn't cause the failure,almost any oil can claim that,as it isn't the oil,but the impurities that get into the oil that causes the damage.
#200 I would say that fear of the past and good marketing are at work in the 3k oil interval change cycle.
When I had a 70 VW bug and it burned regular leaded gas, 3k was even too long.
The oils sold on the market today [if they wear those standard logos], are by and large better than they have ever been.
Most car manufacturers have since gone to 7.5k and in some cases (MB E-320) have gone to 10-15k) The 3k oil change cycle is really almost 60%- 2.5x more frequent than you really have to.
Also the manufacturers hedge, by saying there is a severe duty table also. Whether you are fearful or have no fear, we take a lot on what we want to believe, sans a real oil analysis. (which I am getting the feeling not many folks actually do)
The other good news/bad news is that the cost to manufacture conventional oil and synthetic oil is virtually the same. As most would note, there is a big diffence in the sale price.
I'm looking for a synthetic to use in my 5-spd gearbox (Ford Ranger). All their manual calls for is AT fluid per some Ford spec. Are their different weights to AT fluid, or is it all pretty much the same? I'm about to replace it for the first time at 50k and would like to go to a synthetic.
Comments
amsoil oil and air filters.I also use the by-pass
filter and have been changing oil once a year at
about 14k miles.If you are leary of the one year
then take oil samples to reassure you.it's almost
defeating the purpose of synthetic oil not to go
the full year.
filters to a finer degree than the mobil one
filter.the leading filter makers seem to stress
percentages and housing strength and never say
how small a particle it will filter,I don't care
if my oil is being filtered 10 times a minute
if the filter is not stopping the smaller
particles.the by-pass filters to below one micron
this virtually eliminates wear caused by solid
particles in the oil,plus you get to use an extra
qt. or 2 depending on filter size.
Keep your oil changes to what the manufacturer recommends.
engines using amsoil and have gotten good readings
even at hi mileage.I think alot of the acid and
dilution would depend on location,time of year
and driving habits.
I have also used the oil sampling that the
catapillar dealers sell.
My motive is that I think it is the best product
out there,I am a dealer mainly to get the product
if I sell to individuals I sell for dealers cost.
I'm not sure about redline but amsoil makes the
only syn. atf fluid so that eliminates other
brands,they make a "oiled foam" air filter that
is much cheaper than k&n.they make the bypass
filter,(there are a few other brands out there
but not the exact same kind)I think these help
when you have a 4 cyl.holding 4.5 qt. and using
this gives you an extra qt.I think mobil one is
the next best syn out there but I think amsoil
has a better array of products to compliment the
oil.I think the only way to conduct long term
tests would be to buy 2 of the same car one with
syn. one without and give them to one driver
and tell him to switch cars every day till you
get a few hundred thousand and then take the
engines apart and compare.
I use it in my '97 Bravada AWD, both the tranny and transfer case, using 30K miles replacement intervals.
My second of two bits is that you get what you pay for. There are so many products in the market that you have to really do your homework if you are either that worried about it, or you really take engine science seriously.
Hi packman2, remember me?
Hey oilcan2, is it true that some synths are biodgradeable?
filters a dual remote,it is a reg.filter and the
one used in the by-pass mode,the first by-pass
filter they made was the seperate one I mentioned
before,I have never had one clog up on me so I
assume it is working as long as oil passes thru
it.also why is the syn.going to have dif.benifits
if we use it right away or wait a few thousand
miles.I've read alot of posts about what the
manufacturers say,for years they had nothing
good to say about syn oils,in the past few years
some of the higher priced big three cars are
being shipped with syn oil.
Though, in the manual, GM recommends using synthetic oil - while only in the very cold places.
TB
MB E320 (that I know of) comes with synthetic oil, and the first oil change is due @10k to 15k.
Seems like when the manufacturer/dealer pays the tab for the maint and oil changes they want to extend the intervals (and can for the superior synthetic oils).
I have been on 15k change intervals and in effect do 4 less oil changes, (80% less or 5x more [using the 3k interval}) depending on your point of view. I like using less oil products, saving time and money.
for 7500 mile oil changes. Since yours is still
under warranty I assume that you have a newer one,
and that MB has extended the oil change intervals.
I personally change even below 7500 miles, but
this is only because of two reasons:
a) It is so very easy to change oil on an MB.
b) It might be my own superstition, but I would be
concerned about particles after 15K miles.
All this probably will make little of a difference
in the end, but engine oil seems to be such an
emotional subject, that I'd rather stay in my own
comfort zone.
Yes, Y2k model yr. Less than 1k on the clock, so not even close to the oil change interval. Yes the old habit of 3k oil changes dies very very hard.
A good reason for increasing change intervals is the environmental impact as well as the cost savings. This is the reason Europe is going to 9K+ intervals regardless of vehicle.
I have read that most (if not all) new cars in Germany are filled with synthetic, and you would have a hard time finding petro-based oils there.
In response to markbuck's question on acids and such, high quality oils contain corrosion inhibitors, oxidation inhibitors, and emulsion modifiers to protect against the acids from combustion. These additives are designed to coincide with the recommended change intervals. However, you should always have your oil analyzed at least once a year to determine if there are problems within the engine that increase combustion by-products from normal levels.
I have occasionally used oil analysis, but mostly as a result of some concern, to determine if I have any engine damage.....
To spend $15-20 a year on analysis is just a given, no matter how you change your oil.
Given your situation with low yrly miles and stop and go in a high temp and humidity climate (I lived in Miami, Fl for a number of yrs) I wouldn't have any hesitation at using/switching to synthetic and going to a yrly oil change as you plan. It is a good idea to take it on a longer trip say once a month or more, if you are a low milege user. Of course, the party line is that you should not exceed the warranty reccommendation.
Shelby was smart enough to know that synthetics make a big difference in the longetivity of the engines and turbos.
I use Amaoil in all my cars and drain them every 2 years or roughly 20K miles. I also use the Amsoil by pass filter and their oil wetted foam air filters.
Past experience via oil analysis indicated no problems and on one engine, when I replaces a head gasket at 110K miles, the engine was perfectly clean, hone marks still visable, no ridge or taper in the cylinder bores etc.
I wouldnt use anything else. Amazing how all the other comapnies are jumping on board, now that they see a niche market. Too bad, I'll stick with the Amsoil.
Later
While the conventional oil is better than it ever has been (meeting much higher technical standards), I agree with you that the synthetic is the superior lubricant. And on a interesting level the marketing for conventional oil seems to be doing better, judging by the numbers and %'s that still stay with it.
park sw for 8 years,change about every 3.I can
drain my torque converter and get 100% out of the
trans.On cars that cannot I would take the oil
to one of those shops that has the machine to
flush the trans and have them install the fluid.
The car has 235,000 miles and has never had trans
problems.
few companies making syn. trans fluid,so
maybe thats why amsoil was recommended.Your
buddies engine would have been a perfect case for
oil analysis,if the sample came back bad then
you could really blame the oil,if the oil tested
ok then why did the bearings burn up,did he put
the oil in a car with 80,000 miles on conventional
oil and expect the worn bearings never to
wear out?what oil was it,did he change the filter
during this time?
The cost factor is different for every individual
for me it is worth it,every car is different,and
has different wear and tear,generally speaking
you can get at least twice the use out of syn.
trans fluid vs. non-syn fluid.
P.S.This topic is getting like the ZAINO and non
zaino topics.
Falex:
Amsoil 15w-40 passed at 9 teeth
Mobil-1 5w-30 passed at 12 teeth
Mobil-1 15w-50 failed
Also, Amsoil showed better scores in oxidation tests.
Additionally, Amsoil shows less wear in their 4-ball test:
http://www.amzoil.com/facts.htm
I find it interesting that Mobil-1 makes no claims about wear testing or extended intervals on their website as explained here is an excerpt from "The Motor Oil Bible", an article obtained from another Amsoil website (http://www.bestsyntheticoil.com/amsoil/index.shtml):
"In my opinion Mobil 1 oils are most likely good for 10,000 to 15,000 miles, but the company does not make that recommendation. I have known of many people who do very well running Mobil 1 for these intervals, but it has not been designed specifically for extended drain use. Moreover, the company probably would not back you if you had any mechanical problems resulting from such extended drain use, since they only recommend 'manufacturer recommended change intervals'".
Now, don't get me wrong. I'm not saying Mobil-1 is a bad oil. I think it is an extremely good oil to use, and I have been using it for years. However, Amsoil appears to be better and backs up their claims with testing, technical properties, and warranties.
Conventional oil changes over 12K miles:
20 quarts x 2.25/qt. = $45
4 filters x 5.00/ea. = $20
Total cost = $65
Extended drain change at 12K miles:
5 quarts x $7.95/qt = $39.75
1 filter x $10 = $10
Total cost = $49.75
So, not only do I save over $15 (which BTW pays for an analysis), I perform 3 less oil changes which contributes to less oil in the refining plants, and less to recycle which is better for the earth. Makes perfect sense to me.
BTW, this is from the Amsoil website:
"AMSOIL products clearly offer better wear protection than competitive synthetics and much better protection than conventional oils. Engines can fail due to mechanical problems even when using AMSOIL. AMSOIL Motor Oils, however, in over twenty-five years have never caused an engine failure. If you ever hear someone say AMSOIL caused their engine, bearings, pistons, etc. to fail, they are wrong."
Still not convinced that premium synthetics are worth it for motor oil
I also owned an '89 Volkswagen Fox about 5 yrs ago. Used all conventional oil (Mobil) with off-the-shelf filters and it ran clean, even up to 5,000 mi. between one of the changes. The only reason I still don't own it is because it got wrecked. Maybe it was the condition of the engine. I've read few complaints about VW engines!
My stance on it,is that if your engine is not in good condition when you start using a synthetic,alot of times,they will leak.
From talking to a manufacturer engineer and a CATERPILLAR analyst,I use a premium grade 15w40 fleet oil.I have a 70 chev 4x4 with 330,000 miles on the engine,oil changed every 5,000 miles(I have no warranty to worry about),same brand and weight oil since the engine was new.I always love when they say that the oil didn't cause the failure,almost any oil can claim that,as it isn't the oil,but the impurities that get into the oil that causes the damage.
I would say that fear of the past and good marketing are at work in the 3k oil interval change cycle.
When I had a 70 VW bug and it burned regular leaded gas, 3k was even too long.
The oils sold on the market today [if they wear those standard logos], are by and large better than they have ever been.
Most car manufacturers have since gone to 7.5k and in some cases (MB E-320) have gone to 10-15k) The 3k oil change cycle is really almost 60%- 2.5x more frequent than you really have to.
Also the manufacturers hedge, by saying there is a severe duty table also. Whether you are fearful or have no fear, we take a lot on what we want to believe, sans a real oil analysis. (which I am getting the feeling not many folks actually do)
The other good news/bad news is that the cost to manufacture conventional oil and synthetic oil is virtually the same. As most would note, there is a big diffence in the sale price.