My '97 540i didn't come with an owners manual, so I printed one off the internet, but it was for a 2000 model. The manual stated that the v8 needed synthetic oil. So I've been using only synthetic for the past year. I went to the dealership to buy a filter and oil this morning, and the guy asks me what year my 540 is. When I tell him its a '97 he asks why I'm spending all this money for synthetic oil when the engine doesn't need it? After speaking with him for a few minutes I learn that v8 engines made after '99 need synthetic oil. Supposedly conventional mineral oil is just fine for '97s and '98s.

I'm planning on selling the car in the next 6 months to a year, so I really don't care about keeping the engine working for another decade. Is it OK to use regular 10w-30 oil? Do the indicator lights on the dash assume I'm using synthetic or regular oil?

Thanks guys

Personally, unless your car specifies syn, I'd use regular oil.
There are many real high quality reg oils on the market that aren't nearly as expensive as syn.
The fact is that oil in an engine gets contaminated, syn or not.
I use the approach to change the oil more often, keeping fresh oil in the crankcase.
Unless you like expensive changes use high quality reg oil.
Just my .02

:cool

As a lab test engineer, I tested oils of all types in the largest research facility east of the Mississippi. We ran dozens of concurrent lubricant tests on engine dynos, chassis dynos and chassis simulators. Many tests were severe duty taxi and police cycles with greatly-extended oil change intervals. I can tell with no hesitation that abused API-approved full synthetic with 75K miles on it will result in less wear than fresh conventional oil poured out of a bottle. In modern normally-aspirated vehicles with healthy EFI systems, particulate & acids are less of a problem than most folks assume.

I have used Mobil 1, since first lab testing it 28 years ago. I witnessed conclusive and remarkable industry-std engine teardown results. For the record, I did not work for Mobil Corp as they were our competition. My commuter car currently has 275K mi on the original motor and it burns no oil and runs SAME as new. Since buying this car used 200K mi ago, I switched to synthetic with oil changes every 25K mi!!!! This car has seen about 35K track miles at wide open throttle. In my case, extended oil changes are actually cheaper than using conventional oil at the recommended interval. The cost of oil filters is less and I spend less time under my car doing service. You will get at least 3x the wear with conventional oil (assuming fresh air filters and other precautions), even if you change it every 3K mi.

Synthetic oil offers several advantages that fresh conventional oil can not:

1) lower friction
2) lower engine wear
3) better stability under high temp extremes
4) better viscosity stability with use
5) less deposits
6) better fuel mileage
8) less cold start wear. Approx 80% of engine wear occurs during warmup.
9) far better lubricity at low temps
10) better shear protection & oil control (pressure/flow) at extreme temps

Conventional oil offers one characteristic that synthetic can not quite match:

1) dino tends to cling or stick to surfaces during extended storage. This offers benefit in rare cases where a garage queen might not see startup for several years. This characteristic tends to decrease rust and reduce bearing wipe on startup, again, if the motor does not see use for years. This is a non-issue if your car is started every 6 mo or so.

Hope this helps.

My commuter car currently has 275K mi on the original motor and it burns no oil and runs SAME as new. Since buying this car used 200K mi ago, I switched to synthetic with oil changes every 25K mi!!!! This car has seen about 35K track miles at wide open throttle.


:eyecrazy you have 35K track miles on your commuter???!!?!?! wowo. how many are on your "non-commuter"???

very insightful post, i'd like to add. now i don't feel bad about being late on my oil changes (i'm running mobil1).

So would you recommend using syn in my car even though the S38 wasn't designed for syn?

Figures I'd get owned by LSCMAN... :D

I have a few questions. First off I heard that switching from conventional oil to synthetic is not good for the car. Also I was told that Bimmers do not require oil change every 3k miles but rather every 7k i believe. I have a fealing that both of these statements are wrong but thought i would ask. I am getting ready to do an oil change on my '91 m5 and i only want the best for it. And while we are on the subject what should i get for my oil change. And transmission and diff fluid. Also is there any difference in filters?

My commuter car currently has 275K mi on the original motor and it burns no oil and runs SAME as new......with oil changes every 25K mi!!!!

Very insightful and informative post.

Should I also switch to Mobil 1 Synthetic and change my oil every 25K miles? Would you recommend doing the same thing on all my cars? For that matter, should I use Mobil 1 Synthetic on all future cars I own, no matter the make and model?

Thanks


Hmmmm... should I also switch my ATVs and snowmobiles to a synthetic oil?

This post sure made me want to switch! I'll stick to changing every 10k miles... but I won't be as anal about it as I am with natural oil.

As a lab test engineer, I tested oils of all types in the largest research facility east of the Mississippi. We ran dozens of concurrent lubricant tests on engine dynos, chassis dynos and chassis simulators. Many tests were severe duty taxi and police cycles with greatly-extended oil change intervals. I can tell with no hesitation that abused API-approved full synthetic with 75K miles on it will result in less wear than fresh conventional oil poured out of a bottle. In modern normally-aspirated vehicles with healthy EFI systems, particulate & acids are less of a problem than most folks assume.

I have used Mobil 1, since first lab testing it 28 years ago. I witnessed conclusive and remarkable industry-std engine teardown results. For the record, I did not work for Mobil Corp as they were our competition. My commuter car currently has 275K mi on the original motor and it burns no oil and runs SAME as new. Since buying this car used 200K mi ago, I switched to synthetic with oil changes every 25K mi!!!! This car has seen about 35K track miles at wide open throttle. In my case, extended oil changes are actually cheaper than using conventional oil at the recommended interval. The cost of oil filters is less and I spend less time under my car doing service. You will get at least 3x the wear with conventional oil (assuming fresh air filters and other precautions), even if you change it every 3K mi.

Synthetic oil offers several advantages that fresh conventional oil can not:

1) lower friction
2) lower engine wear
3) better stability under high temp extremes
4) better viscosity stability with use
5) less deposits
6) better fuel mileage
8) less cold start wear. Approx 80% of engine wear occurs during warmup.
9) far better lubricity at low temps
10) better shear protection & oil control (pressure/flow) at extreme temps

Conventional oil offers one characteristic that synthetic can not quite match:

1) dino tends to cling or stick to surfaces during extended storage. This offers benefit in rare cases where a garage queen might not see startup for several years. This characteristic tends to decrease rust and reduce bearing wipe on startup, again, if the motor does not see use for years. This is a non-issue if your car is started every 6 mo or so.

Hope this helps.

Yep...this is all good stuff, I love it...a knowledge sharing thread from someone who knows. PERFECT.

One thing I would add, back 4 years or so I raced Superbikes and 600 Supersport machines for various factories up here in Canada...had one tuner/engine builder tell me about MOBIL1, and how it has the best HEAT TRANSFER qualities of any synthetic...and this is very important because the 600cc and 1000cc motors use an oil to water heat exchanger and also the motor it's self is a great heat sink (to remove heat) from the engine. I have always remembered this and when I read the 540 "cooling issues threads", I cant help but think my 7.5L's MOBIL1 is doing its damn'dst to remove the heat from my hot motor.

Has anyone (LCSMAN) got info to back this up???

Thanks.........out

I have a few questions. First off I heard that switching from conventional oil to synthetic is not good for the car. Also I was told that Bimmers do not require oil change every 3k miles but rather every 7k i believe. I have a fealing that both of these statements are wrong but thought i would ask. I am getting ready to do an oil change on my '91 m5 and i only want the best for it. And while we are on the subject what should i get for my oil change. And transmission and diff fluid. Also is there any difference in filters?

It is never too late to switch to synthetic....it is always good. Whenever you do switch, wear will almost stop. BMW recommends fairly long oil change intervals compared to domestics....7K sounds right. The only drawback to synthetic motor oil is it can encourage weak gaskets to leak more. If your gaskets seep on a high mile, aging car, the synthetic will cause more leaks. My strategy is to replace the bad seal or gasket instead of nursing it along.

Get whatever viscosity is recommended in your Operating Manual for your climate and duty.

I would recommend GL5 synthetic gear lube in the appropriate viscosity. I'm guessing 75W-90 for E36.

I can not advise you on E36 5spd manual lube as I think it's a ZF tranny. I personally prefer BMW sourced lifetime manual tranny lube for my 6spd Getrag, but changed every 30K or so. I do not care about shift quality...I care more about wear & lifespan. This is why I do not run alternative, non-approved tranny fluids. Any cheap, thin tranny lube will improve synchro engagement and shift feel....as it prematurely wears out your tranny.

I use Hengst filters, same as BMW original equipment. Incidently, I noticed Hengst comes in a Purolator box at Pep Boys.

So would you recommend using syn in my car even though the S38 wasn't designed for syn? :D

My 17 year old Ford former track (current commuter) car was not designed for synthetic either! Keep in mind that no cars were "designed" for Mobil 1 or similar synthetics in the late 1970's. This is when I began using synthetic.

"Some" engines that are not designed to run synthetic can exhibit break-in issues. Conventional oil engines "generally" have wider tolerances and rougher cylinders, rings and pistons. In these cases, a non-synthetic should be used during the break-in period...in order to ensure break-in. Break-in is actually wear-in....where high spots rub off & parts begin fitting together better to reduce ring blowby etc. If a motor does not break in, it can consume excessive oil. Synthetics prevent wear-in/break-in because they are so good at preventing wear. Newer BMW's and similar cars designed for synthetic can use it from day 0. They have highly polished cylinders and rings that need no break-in. In a conventional oil car, you are better off waiting until the motor has about 15K miles on it and oil use has dropped & leveled off before switching to synthetic. Once you switch, break-in activity will end. The mistake some folks make is to dump low friction synthetic in a freshly rebuilt motor that shows high oil consumption. Such a motor will NEVER break in. The hone marks will eventually lose their cutting ability due to malleability of metal and it'll be a smoker for life. Obviously a used car with the original motor has no break-in issues to address.

My list of synthetic oil benefits should also include:

1-3% more RWHP
1-3% cost saving in annual fuel use...this benefit alone sometimes covers the added cost of synthetic. Longer service intervals are not always needed to save $.

Also, the horsepower % gains are almost linear across the whole RPM spectrum, not just a spike. This offers real benefits compared to some power adders that offer 5 or 6 HP at a certain RPM only & may even give up a bit of power (torque) at lower RPM!

Lscman gets my vote. :alright

I would disagree with it's never too late. As a rule, I suggest sticking w/ dino juice (conventional oil) if the motor's never seen synth in its first, say, 100K miles. Full synth flows sooo well it will "find" any little crack or sloppy seal in the motor and will leak. It will clean out all that dino that's been sealing the imperfections caused by wear over the years.

I'll never forget my first oil change in my Turbo Supra. I didn't know the previous owner ran full synth. I also didn't know how incredibly large the drain plug is on that car! What a mess. That stuff comes out looking as good as dino goes in-- and five times faster! -scott

It is never too late to switch to synthetic....it is always good. Whenever you do switch, wear will almost stop. BMW recommends fairly long oil change intervals compared to domestics....7K sounds right.

I'm convinced, synthetic for all my cars from now on.

LSCman, please be more specific about oil change intervals. You said your commuter gets its oil changed every 25k miles, what about your 540?

Will my 4 stroke atv benifit from synthetic? How about a 2 stroke thats oil injected?

Thanks

BTW, LSCman, I read all 350 of your posts while slacking off at work today, and I must say, it was probably the most productive and entertaining thing i've done on this forum for awhile. Your are just as witty as you are knowledgeable.

i think my screen name thru you off. i dont have an e36. i have an e34 m5. that is what i heard would happen if you used synthetic. that it might cause leaks on older seals. what is the most expensive seal to replace on an engine? how much could i be looking at. is it something i can do myself. i just want to get an idea of worst case senerio before i make the switch.

One question, especially for the guy asking about ATV's - what about AMSOIL? I know they are the top oil used in most all 2-stroke racing circuits, but, how much better is it than Mobil 1?