Im in Florida and deciding between 5W 40 or 10W40 non synthetic.

Also, thinking about Liquid Moly

Thanks,

I am back to using 10W40 non-synthetic on my car out in California. The dealer always used 10W40 as well from day 1.
I used 20W50 to cut down on oil consumption but it actually did not, so back to 10W40. I also used 15W40 Diesel oil for a while but found that it cleans the engine parts "too much" and actually increased oil consumption.

- Cheers!

I use liqui moly 15w40 diesel oil in my 2.6. Since 112k miles to 122k but it sat still for half it’s life. I did not think it really consumed oil until dolucasi mentioned it. But at the same time I still have an oil leak to fix at the timing cover.

It's best to use what's recommended in the owner's manual. Gas powered cars shouldn't be using diesel oil and it's a waste of money to use synthetic oil in cars that already have many thousands of miles on them. Synthetic oil provides maximum protection when it's used from when the car is brand new.

I must admit that I use synthetic oil in my car and also advised my grandson to use it in the 190E. I changed the oil on the 190E for use in winter where temperatures occasionally reach down to -40 F or C although not often now with climate change. I have found by experimentation that 5W40 Mobil I synthetic oil flows easier at low temperatures than non synthetic. In summer with the 190E I typically switched to 15/40 non sythetic Castrol GT. So far so good!

My engineer father worked for Mobil and knew the man who originally developed the Mobil 1 synthetic oil quite well. As a result of this, I was always taught not to use synthetic oil for cars that already have many thousands of miles on them because the engine wear that synthetic oil is good at protecting against has already taken place in the miles already put on the car so that the synthetic oil engine wear protection becomes much less and not worth the additional cost of the synthetic oil. Synthetic oil is more of a big deal in modern cars with engine clearances much tighter than our W201s which then necessitate the thinner synthetic oil being able to cope with such tight clearances.

I chose the liqui moly diesel because I wanted the extra lubrication for my motor being static so long and knowing the m103 can run very hot. I also live in Ohio the weather is random and we get all seasons.

im curious…will have to find the old service records and see what the dealer used to use back then.

I don't mind the extra cost of synthetic in winter because the car seems to start more easily at extreme cold temperatures.

Gas powered cars are not designed to run with diesel oil. Gas powered cars are also not designed to run on diesel fuel either because diesel fuel is refined so differently from gasoline. I would suggest that you contact the MB Classic Center in California. They can tell you the correct oil that you should be using in your car.

If my memory serves me correctly, I think there are now non-synthetic oils designed to work with the cold temperatures that you face in Canada in the winter. I don't live in the north any more so that's an issue that I no longer have to deal with.

Classic center says they use synthetic Mobil 1 5w40 but aren’t they in Cali where the weather never changes?

my perception of the m103 engine in general is that it revs high and runs hot. My friend who is retired mb mechanic recommended liqui moly diesel for these reasons as it is a race oil if I recall and degrades less with high temps.

I don’t drive my car hard but would like the best protection I’m almost at my next OCI.

My father was an engineer with bachelors and masters degrees in engineering, more than 40 years of aviation and automotive engineering work experience and was a member of the Society of Automotive Engineers. My engineer father never used diesel oil in a gas powered car. I'm aware that since 1997, all MBs now leave the MB factory with Mobil 1 synthetic oil. The W201 model run ended in 1993 so I'm a little surprised that the MB Classic Center would say to use the Mobil 1 synthetic oil for the W201 since the W201 model run ended before MB started using Mobil 1. When my engineer father was manager of aviation technical service world-wide for Mobil, he actually knew the man who originally developed the Mobil 1 synthetic oil. Because of that friendship, I was always taught to only use Mobil 1 synthetic in a car from the time it was brand new because it's during the early miles when the synthetic oil will provide the maximum engine wear protection. That level of engine wear protection goes down if you don't start using Mobil 1 until after the car has already accumulated many thousands of miles and already endured quite a bit of engine wear. Using Mobil 1 in this case is not really cost effective. I actually do use the Mobil 1 5W40 synthetic oil in my W201 because I've been fortunate enough to own my car since it was brand new. You can certainly use the Mobil 1 synthetic but it's more expensive. I actually just dug out my W201 owners manual and it says to check with your MB dealer for oil brand names but it did show some oil weights based on various temperature scenarios which indicates to me that you want to factor in the weather temperature range you'll be driving your car in. You might try to find a conventional oil that is able to cope with a wider range of temperatures. I would think that would be your best bet for Ohio weather. Your local parts store should have the charts for which oils work best in which temperatures. Also, if your car has more than 75,000 miles on it you're probably also better off using 1 of the high mileage oils. Another way to help an engine that runs hotter is to keep the layers of crud that build up in your engine bay and on your engine wiring cleaned off. I used to watch my engineer father do this for just that reason. Be very careful when cleaning to not damage your alternator or short out the engine wiring in the process. I used to watch my engineer father do this for just this reason.

I doubt any topic about engines will have more opinions than "what oil to use? "

This is a quick shot of my log and cars early life, it was shipped to NJ then sent to a FL MB dealer that used 10w40 and looks like they increased the weight to 15w40 when it came to Ohio at 59k miles

when I took ownership I initially put the Mobil 1 10w40 but I recall why I switched to heavier now…because I saw it in the old booklet. I think that weight mostly comes as a diesel oil but that’s where I got the idea anyways

You should NOT be using diesel oil in your gas powered car. Again, my engineer father with decades of engineering work experience and who knew exactly how all automotive oils are formulated NEVER used diesel oil in our gas powered cars. You should stick with the 10W-40 oil for gas powered cars as was indicated in your car's service records. That's what's in the W201 owner's manual. BTW, check to make sure your engine thermostat is working properly.

I wasn’t saying I was going to continue using diesel oil just sharing to explain where I even got that idea and was interested to see my cars limited history. It’s only been in for 1 OCI, only had my car driveable long enough for 2 and liqui moly 15w40 is marketed/labeled as diesel their site says it can be used in both

I need an oil change soon and like the discussion…I wasn’t alive when these cars came out haha. My thermostat is nearly brand new and I don’t have any heating problems but I’ve read that the m103 in general can have a weak spot for high heat and head gaskets not sure how true or frequent that has been but they do rev high having only 4 gears and of course we want to be preventative

There are times in life when the wise thing to do is to listen to experts who have far more years of schooling, many more decades of work experience and who actually belong to the item manufacturing association concerning the issue you're dealing with. This is one of those times. Just as you don't put diesel fuel in a gas powered car, you don't use diesel oil in your gas powered car. They're refined very differently from each other. Using diesel oil in your car will not solve the head gasket issue that the M103 engine is notorious for. You also shouldn't be constantly changing the oil brand in your car with every oil change because small amounts of the old oil can remain in the car and every oil manufacturer refines and uses different additives in their oils. The best way to take care of your car is to do your oil and filter changes at the intervals recommended in the W201 owners manual, make sure your thermostat continues to work properly and don't allow layers of dirt and dust to pile up in your engine bay which alone can cause your engine to run hotter. Those things overall will help your car to run cooler. They're designed by nature to run hotter but you can mitigate that by what I'm suggesting. That's what my engineer father taught me and it's always held me in good stead with my cars.

I think you misinterpret my words as rejecting your advice that’s not the case at all. You and others have helped me tremendously and I’ve taken note an applied much of what you’ve all shared.

My manual lists 15w40 and 10w40 as Year around oils and recommends changes every 7500 miles or once a year, that’s exactly what I’ve been doing this. I have only driven my car about 11k miles since I started restoring it.

The bottom line is that you should not be using diesel oil in your gas powered car. No where in your owner's manual does it say you can do that.

https://www.benzworld.org/threads/co.../#post-3189106

Some diesel oils meet MB spec. Lots have changed in the lubrication world since the 1980's. The diesels engine oils have a higher TBN number (Total Base Number) to neutralize sulfuric acid. I don't think that is as important today because in the US you can only buy Ultra low sulfur fuel. Also, diesel oils have a greater detergent package that would be advantageous in gas engines that have been abused with extended oil changes. You can't be too clean when it comes to hydraulic lifters.

Anyways, the reason I asked my question is for the weight of the oil. Im in Florida. My 190e 2.6 new to me has 255K miles. I get that lifter taping on start up. So, I'm between, 10w-40, 5w-40, 15w-40.
All non synthetic.

No offense Dave, but my engineer father with more than 40 years of aviation and automotive engineering work experience and membership in the Society of Automotive Engineers would strongly disagree with you. As part of my engineer father's engineering work experience, he knew how every aviation and automotive oil was formulated. He never used diesel oil in our cars. Given the high mileage on your car you're best to stick with a non-synthetic oil that's designed for cars with a high mileage. The extra protection that synthetic oil provides happens in the early miles so that protection wouldn't be of much benefit to your car now with its high mileage. You're best to stick with the oil weights that are recommended in the W201 owner's manual. BTW, I used to live in Florida, I'll never miss hurricane season.

used to run semi-syn 10w40, plan to run 5w40 full-syn, Im in the process of refreshing the engine, figured thinner oil will do it good, but you know the diff between 5w40 and 10w40 is quite small, its more the semi-syn vs syn that makes a diff imo, I see no reason to run dyno oil, price diff isnt much and by all accounts Ive read over the last few years, these days syn is a better product
btw I live in a pretty temperate climate, winters rarely get below negative 10C and summers are around 30-35C, but this car is done with running winters though, so Im not accounting for low temps much


Best,
Dan

My engineer father actually knew the man who originally developed the Mobil 1 synthetic oil. Because of that, I was always taught that using a synthetic oil in a car that already has many thousands of miles on it really wasn't worth the extra cost because most of the engine wear that synthetic oils are good at protecting against happens during the early miles.

Sorry I forgot to mention that the lifter tapping you're hearing on start up is pretty normal so long as it's within reason. You can certainly post a video of your car at start-up and I'd be more than happy to view it to see how it compares with my car. BTW, he W201 owner's manual recommends 10W-40 for oil.

I'm neither an engineer, nor a mechanic, but...

I've used everything from Liqui Moly to Delo to Mobil1 to private label SuperTech (Wal-Mart), and even synthetic/synthetic blend. I live in So Cal, desert area and the temps are for the most part 75+ except for summer when it goes to 100+. The things I do is use a good quality filter (usually Hengst or Mann), ALWAYS utilize the SAE weight grades (because of my climate I won't run anything less than 10W-40), and I always do my oil changes like clockwork, period. Usually every 7500 - 8000 miles, sometimes a bit sooner. I'm due for my next change in another couple hundred miles and I already 6.5 qts of SuperTech 10W-40 synthetic blend on standby. Currently I have Quaker State 20W-50. Also, as a side note, MB does not appear to make a distinction between oil types for their diesel and gas models, only that certain guidelines are followed for the ambient temperature ratings.