Better to go by mileage than time. How many miles or Kms did you drive the car in the two months. Yes, these cars tend to use oil. Mine burns about a liter every 1000kms. The harder I drive the car, the more it uses. Make a habit of checking your oil at each fill up.

 

It might be close 1000 kms as well. Interesting for me to learn. So would the same diesel burn oil if it was factory new also? Or would the amount burnt change? If this is the case what exactly causes the amount of oil being burnt to increase with the car getting older?

 

There are lots of claims as to what is considered standard for oil consumption on these cars. Someone posted an image from their factory service manual that stated that it’s normal to burn a liter every 250kms! Sounds excessive to me. Others joke that you should start to worry when your Merc diesel stops burning oil. From what I have read, these engines consumed oil right off the factory line. As the piston rings wear, oil will leak into the combustion chamber and burn off. If you haven’t done so already, do a compression test on each of your engine cylinders. This is one good measure of the health of the engine. If the engine has low compression then piston rings are worn. In my opinion, a liter every 1000kms is nothing to worry about. Always keep extra oil in the trunk and top off when needed. Enjoy!

 

How was it before the switch to LiquiMoly? Was oil disappearing? What oil were you using?

My 300D didn't burn oil. I changed it every 2500 mi after realizing 3000 mi was too long per owners manual.

Started with 15W-50 Mobil 1, then used Castrol Syntec 5W-50, and eventually 229.5 Mobil 1 Euro 0W-40...

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LiquiMoly service offered me their 10W 60 today, saying it is durable to high temperatures and won't be consumed as much as 10W 40. Does that make sense?

How was it before the switch to LiquiMoly? Was oil disappearing? What oil were you using?

I didn't try any other oil before. I bought the car 6-7 months ago and changed its oil to LiquiMoly

I should also note that many people love the shell rotella 15w-40. In warmer climates like yours, you could even consider going to 20w50. Be careful with questions related to which oil to use as it can initiate a “lube war”, as one member so aptly coined

I might try 15w 40 or even 20W 50 as you said. Actually my mechanic suggested me to use 20W 50. But here in the winter sometimes it gets to minus degrees like -1 or -2 degree celcius, though I don't know if this is anything to worry about.

 

According to the owner's manual, the oil you are using right now is adecuate, so don't worry about it.

Regarding the oil consumption, just keep an eye on it. Measure it regularly and always carry a quart of oil in the trunk so you can refill it as needed. The important thing here is not to allow the level to fall below minimum.

Owners manual, page 90:

 

Yep , 15 and 20W takes a year to circulate from a cold start and upon that cold start is where most metal to metal wear takes place .

What people don't know is a 10W60 will be thicker when COLD that a 10W40 !!

The newer Mercedes oil specifications are far better higher oil quality and their performance profile smashes the old previous specs .

It's all down to oil quality , the oil basestocks used ( groups ) and additive package .

And in general the thick stuff is less quality purely relying on thick viscosity to maintain oil film strength , but this is completely false .

A mechanical engineer who researched tribology tested over 230 oils for oil film strength....

 

While I've stopped driving my 300D for a long time I do not remember any sort of oil loss between 2500 mi oil changes with over 300k mi on the ODO.

Maybe mechanic can do a compression test?

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I will definitely do a compression test. But with regards to oil consuming what does compression test indicate? What if the pistons have good compression and what if they are bad?

 

I love buying the finest oils I can afford. However..... burning 1l per 1000kms would really affect my oil choice. If it's going up in smoke that fast, I'd be considering an economic multigrade or entry level semi synthetic from a reputable brand - one designed for 'older automobiles' in a big 10litre tub, based on the reasoning that the benefits of the finest oils are being mitgated somewhat by having to change/top up the oil at such a high rate. Basically - It's a bit rich burning liquimolly's finest at that rate in my opinion! Suit yourself though of course.

 

I'm a 15-40 Rotella guy. Think about your seals and gaskets... some of the newer fancy oil concoctions do not play well with 30+ year old seals & gaskets.

 

From the service manual….

 

I second the use of Rotella in the diesels. I am in the agricultural world and we maintain many diesels spanning from 1949 tractors, mid 80s heavy generators, trucks, harvesters , and several MB sedans an occasional puck up and even a diesel powered RV. We have used the Rotella for years and have been very satisfied with its performance. It is specifically formulated to run in diesels, a factor you should carefully consider.

 

264 engine oils tested and Rotella 15W40 comes in 207th , I wouldn’t even use it as a flushing oil !

 

@Gazwould - the text size in your post - . Probably is what many would consider a 'flushing oil' if you have modern motor or a 6.75l classic rolls or another older more expensive prized automotive posession. I think you are missing the point though.

What's the service interval for oil change on an OM615? 5000kms?
How much oil does the manual say it consumes - 1 liter every 4000kms?

I had a quick squiz at 'Shell Rotella T4 Conventional Diesel Oil specs'. The label smacks of a basic Multigrade that conforms to some basic modern specs, and most notably - Mercedes Benz Spec 228.31.

If the Shell 'Lubricant selector' recommended to me a full synthetic similar to what we run our modern highly charged 200plus hp four-pot Euro-wagon's with their 10,000mile or more service intervals on I'd be like - 'whatever - get the hell outta here' and then I'd ignore Shell and go look at some competitors websites. Same attitude if somebody on a forum or a man behind the counter at the local car spares distributor gave similar to me and reached for the top shelf oils even after hearing I drive a 1970's 240D.

Many, most probably all actually of the recommended oils probably compares poorly in a supertest vs the full range of available oils. I imagine that's by design, not because they are trying to sell us an inferior product. I assume a lower price matches a lower spec. Number 207 out of 264 engine oils sounds like exactly what I'd expect to run my old reliable 1970's diesel donk on with 55hp.

 

I agree with squibby, I cant complain about the apparent success I have had over the years using Rotella. My opinion is "If it aint broken dont fix it" : "if it works good for you keep doing it".

 

Yeah, I ride a modern motorcycle but it's a 1200cc twin with only 93hp. That's pretty pathetic for a 1200cc motorcycle engine these days - it's obviously an under stressed engine. Yet if I go on some websites 'oil selector' they recommend some expensive ten-tenths full synthetic special ester formula what not super oil for twice the price of a semi-synthetic. You have to recognize when you are unnecessarily being given the 'UP-SELL' with engine oils. It's the most provocative and debated and controversial conversation we can have on the forum and none of us will ever agree. But one thing is for sure, an OM615 doesn't need no fancy oils to be reliable if serviced to the intervals from what I've heard and read. That being said, I imagine it's going to just love a liquimoly full synthetic if you want that warm fuzzy feeling that comes from the best oil you can afford and if you are lazy and don't get around to changing the oil as much as you should, an expensive modern long life full synthetic probably has your back and is going to take care of that engine for you a lot longer after a cheaper multigrade starts to degrade.

 

And for Hot climates? Where I live the coldest month of the year is a 15 degrees centigrade (59 Fahrenheit). Hottest month is 25 centigrade average (77 Fahrenheit).

 

20w50 is perfectly for you.

 

When I had my 1984 300D, ran Rotella 15W-40 and never had to top off the oil between my 3000 mile oil/filter changes. Car eventually ran over 300,000 miles before transmission geve out and became a parts car. Same for a 1982 240D - no oil between changes. Sold it and don't know how far it eventually ran. SAE, API and others spec engine oils for a reason - if it meets the diesel specs, then the oil is just a s good as the next oil that meets the specs. Advertising hype is what fuels all the lubes wars we have seen on this forum. (Everyone has an opinion and like $%@ holes, they all stink.)

 

This could be a repeat because I did not read all of the other posts.

In the Fuel Supply Lift Pump that attaches to the Fuel Injection Pump there is a 5mm O-ring. When that O-ring wears some have claimed that some of engine oil that lubes the fuel injection pump is sucked into the diesel fuel and goes on to be burned with the fuel.

The Engine itself. No good Valve Stem Seals and or worn-out Valve Guides and Valve Stems can be a source of Oil getting into the combustion chamber. Changing the valve stem seals has worked for some bit did not work for me.
Next is the piston rings and piston ring grooves or sticky piston rings.

After sitting a year not running my Volvo 244GL Diesel would smoke gray with an acceleration.

I was skeptical about using Marvel Mystery Oil poured into the cylinders by way of the glow plug holes would un-stick the piston rings but at the time it was a rather cheap $8 USD per bottle. I did a full week soak and rotated the engine and poured some more in but only got to do it for 1/2 week as I had to get the car on the road.
Note don't drive with the MM oil in the motor oil. I don't care what the ads say about the stuff. Not good to have in diesel oil. I drove the car around changed the Oil and went for a ride on the freeway. It was at least 1/2 better and in about a week the gray haze was gone.
Others have done the cylinder soak and had their compression rise after it. I did that on my 300D to no effect on the compression. So, unless you have sticking piston rings it won't work.

 

You wouldn't think a valve job would make a difference on a running diesel. I did a valve job on a couple of OM617s several years ago, and they fired up with about a half revolution of the engine. Amazing change in performance.

 

By valve job do you mean changing the stem seals?

 

No, I'm talking full blown valve job. The guides are the problem. I'm saying if your car starts fine and has decient performance, don't spend the money. The jobs I did involved serious overheating and cracking the head. As an aside the diesel engines with the worst wear were driven around town. If you want to buy a used diesel, buy one with high highway miles.