I don't want to start an oil thread about the pluses or minuses about synthetic/semi-synthetic oils. I would like to know simply why "semi-synthetic" oil exists. We all understand regular motor oil and synthetic oil have their definite advantages, but why would you use a half-and-half combination? I know it's cheaper than full synthetic, but isn't that false economy? It's almost like brushing your teeth without toothpaste, or changing your oil without changing the filter - you're only completing a partially effective action. I noticed that Saab routinely uses (and I'm sure others do too) "semi-synthetic" oil for their late model cars. It just doesn't make sense to me.

Why don't you want to start another oil thred ?
You already answered your own question, $$$$$$$$$$$.
Maybe it's an oil specially formulated for people who can't make up their mind.

__________________
2007 C 230 Sport.

There's got to be more to it than just the money. It still screams false economy.

Pure marketing positioning.
A low cost dino, a mid-price semi and a high price synthetic.
For car enthusiasm, costs may not be an issue, but for Mr. Joe-Normal Consumer, price is a more sensitive element.
JackD
....all on dyno oil.

It was made for those who are "semi" convinced.

As eluded to above, it's a little like mid-grade fuel. If the low-end unleaded isn't up to snuff, then use the high-end; not the "semi" stuff.

By the way Jack, I still think you need to keep your 260. Forget the problem-prone latter model you're considering.

I smell an oil war coming on and I've likely just pissed off a bunch of 104 owners.

Oh well..............

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

Perhaps the reason for synthetic blends is that they can be better lubricants than straight synthetics such as Mobil 1 - according to european tests and Mercedes engineers.

MB sheet 229.3 approved oils
for passenger cars with gas and diesel engines with extended drain interval indicator FSS up to 20,000 km, or 40,000 km - 25,000 mi, min. 1.0% fuel saving compared to 229.1, based on ACEA A3 B3. For gas engine of the M100 series, gas engines of the M200 series and diesel engines of the OM600 series (not models with Euro 4 diesel particle filters).

AGIP EXTRA HTS 5W-40
AGIP Synthetic PC 0W-40
AGIP Eurosport 0W-40
Amsoil 5W-30 Synthetic Motor Oil
Amsoil 10W-30 Synthetic
Amsoil Series 3000 5W-30 Heavy Duty Diesel
Aral HighTronic 5W-40
Aral SuperSynth 0W-40
Aral Super Tronic 0W-40
Aviasynth 0W-40
Castrol DCO TOPUP SAE 0W-30
Castrol Formula RS Road and Track 5W-40
Castrol GTX7 DYNATEC 5W-40
Castrol Formula SLX 0W-30
Castrol TXT SOFTEC PLUS 5W-30
CIFAB Synthoil Hydrocrack HC7 5W-40
Elf Excellium LDX SAE 5W-40
Esso Ultron 0W-30 (fuel economy)
Esso Ultron 5W-40
Fuchs Silkolene Pro S 5W-40 - 100% Synthetic Oil For All Race Engines
Fuchs Silkolene Pro S 10W-50 - 100% Synthetic Oil For All Race Engines
Fuchs Titan SuperSyn SL 0W-30
Havoline Synthetic DS 0W-30
Kendall GT-1 Full Synthetic 5W-40
Liqui Moly Diesel Synthoil 5W-40
Liqui Moly High Tech 5W-40
Liqui Moly HC7 5W-40
LUKOIL SYNTEETIK 5W-40
Mobil 1 SuperSyn European Car Formula 0W-40
Mobil 1 SuperSyn 5W-40
Mobil 1 SuperSyn 5W-50
Mobil 1 Turbo Diesel 0W-40
Mobil Synt S 5W-40
Mobil Synt S Turbo Diesel 5W-40
Mobil Syst S 5W-40
Motul 8100 E-Tech 0W-40
Motul 8100 X-cess 5W-40
Pennzoil Synthetic European Formulation 5W-40
Pentosin Pentospeed 0W-30 VS
Quaker State Full Synthetic European Formulation 5W-40
Schaeffer Micron Moly 5W-30, 10W-40
Schaeffer Supreme 7000 5W-30, 10W-30, 20W-50
76 Pure Synthetic Motor Oil 5W-40
Shell Helix Plus S 5W-40 (Mercedes-Benz)
Shell Helix Ultra 5W-30, 0W-40, 5W-40
Sunoco Synturo Gold 5W-40 (introduced January 2002)
Total FINA First 5W-40
Total Quartz 9000 5W-40
Valvoline DuraBlend MXL 5W-40
Valvoline SynPower MXL 0W-30
Valvoline SynPower 5W-30, 0W-40, 5W-40
Veedol POWERTRON 5W-30
Veedol SYNTRON 0W-30

Note that according to Valvoline, their Durablend 15w40 also meets MB 229.1 and AECA.

Some oils which are not recommended:
Mobil 1 SuperSyn 0W-30 SL/SJ/CF A1/B1/A5 9.7 doesn't meet 229.1 nor ACEA A2 or A3
Mobil 1 SuperSyn 5W-30 SL/SJ/CF A1/B1/A5 9.8 doesn't meet 229.1 nor ACEA A2 or A3
Mobil 1 SuperSyn 10W-30 SL/SJ/CF A1/B1/A5 10.1 doesn't meet 229.1 nor ACEA A2 or A3

The six "4's" on Jack's odometer via dyno oil says it all. Guys his age and mine have taken many cars into the mega-mileage range on dyno oil.

If I can drive a car over 300,000 miles on dyno oil, what do I care about an xxx.y standard? This comment is not intended to knock the previous poster...interesting info, but...........

I wonder if profit margins are higher for syn vs. dyno???

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

It's called "market segmentation" - flood the market with every conceivable viscosity range, base stock - useage such as "trucks" or "high mileage" - whatever - and someone is bound to buy something.

Duke

From above:

For a car that does 85% of its monthly mileage on the highway or about 2,500 a month ... how long can a synthetic be left in the crankcase?

Is a 10,000 mile interval OK? I am speaking of the 190e 2.3 specifically.

Haasman

__________________
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)

Yes, yes, yes! It is a market economy. Why you can buy anything, and if there becomes a possibility for something different, someone will be there to invent it! No stone is unturned!

How about a "left nostril inhaler" BB

Given that the recommended change interval for mineral-based oil is 7500 or six months, a full synthetic should be okay for 10K, but why not just use conventional oil and change the oil and fiter every every 7500, which would be three months. Assuming you do your own oil/filter changes, you should save enough in oil cost to make it worth your time. If the engine has low oil consumption, consider a HD diesel engine oil, which will benefit the engine due to its better additive package, but the additive combustion byproducts can degrade catalysts, so only use CI-4 oil if consumption is low.

Highway miles are easier on the oil than stop-can-go traffic, because the oil temperature will be lower cruising at freeway speed than urban traffic and you have less hours on the oil and fewer cold starts the higher your average speed over the interval. Back when my 190 was a daily driver with a mix of city and highway miles I changed the oil and filter every 5K, which was about three times a year.

Now that the 190 is my "winter car" and only gets used on average once or twice a week accumulating 1000-3000 miles over the six months it's in use I change the oil once per year - just before I store it for the summer.

BTW, I will be swapping the '91 MR2 for the Merc in the next week or two. It's always nice to rediscover the pleasant driving charactericts of the 190. Swapping cars every six months keeps them from getting boring, especially two cars with such different driving characteristics. Just got back from a 1000 mile road trip to Nevada City over Thanksgiving over mostly two-lane roads. Highway 33 over Pine Mountain Summit is almost as good as a day at the track!

Duke

For cold weather climates, there may be an advantage. My testing has shown that semi-synthetics do not thicken as much as straight dino at cold temps.

__________________
1986 300E 5-Speed 240k mi.

MikeMurrel: You know, with "age" comes wisdom.
I've spent almost 2 decades in labs and test facilities, developing lubricants of all kinds, including synthetics for a major oil company. What I regularly read about lubricants on several forums makes me laugh and show me how marketing campaigns, advertising and the use of comforting buzz words can influence people and skew their buying power and opinion toward what seems to be (for them) the ultimate products.
During my career, we have tested thousands of lubricants, thousands of miracle recipes, we've tortured engines and transmission like nobody in their right mind would want to replicate in real life, we ran thousands of fleet tests with all sorts of oils, we've worked with hundreds of engineers at Ford, Chrysler, GM, Toyota, Honda BMW and all others.
How about running a real Nascar race car with recycled Dino oil? We've done it with no problem.
When was the last time you heard about an engine problem due to engine oil breakdown. When was the last time you heard of a premature engine failure due to poor lubrication? (assuming prescribed oil change intervals were adhered to.)
One word of wisdom: Change you oil as prescribed, use the recommended grade for the driving conditions and buy
whatever make available that fits your budget.
If a $1.99/qt engine oil meets the above, you're OK.
JackD

Really?

You mean there is nothing really to it?

Your words of wisdom suggest that we are all suckers!

I have seen from my own wisdom, that there is an advantage in the new technology lubricants, not with autos, but instead with tour de france level road bikes, similar to Armstrongs!

Why not in our crank cases too? BB

MrBenz: I have absolutely no problem with new technology, new products or high tech. I'd say I'm a new tech/high tech guy.
If you refer to synthetic oils as being "new technology", you are making a small mistake.
Synthetic oils were first developed by Standard Oil in 1928. Olefin polymerization which gives PAO's, and ester based oils (as those seen today) were on the market in the mid-thirties. The current synthetic base-stocks used in todays' "new tech" oils were developed in the early 1950's.
So much for your "new technology" line.
Not for one moment. Synthetic oils are excellent products and will not cause the slightest problem, but I, and all those who have taken their daily bathe in oil for years (except the marketing guys) will confirm what I wrote earlier.
JackD