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mikkhh

I run 10w40 semi synthetic (since 15w40 is less common and 208l drum price difference is like 10usf and 10w40 is in stock usually, 5 years ago 10w40 semi synthetic used cost half more than 10w40) truck oil with 5-10% gear lube on my benz 3.0l v6 diesel, it is first ones with 18:1 compression ratio and no scr. I have driven it for last 15 000km no problems.

It still has dpf and at first there were dpf faults. First thing I did was cleaned intake + egr cooler and fixed all boost leaks, after that dpf faults went away on their own. One charge air pipe is oily (checked under hood yesterday), replaced seal at first but now will fit whole new pipe. In spring I will remove radiators to wash them.

25 year old inline6 3.2 diesel commonrail benz I ran only on cheap 15w40 mineral or 10w40 semi synthetic. -25c cold starts and 15w40 got along so far, have driven that car for 60 000 miles, engine has at least 400 000 miles on it. 60 000 miles ago I replaced head gasket and seals as a preventative measure.

I used to run earliest no dpf from factory audi 3.0tdi 2005 year on 15w40/10w40. I sold the car four years ago, new owner has driven it and total my + his mileage is like 60 000miles, car total mileage around 200 000 miles. There is no signs of timing chains being replaced and there is no chain rattle on startup.

But main thing that takes a toll on those newer engines that do not cheat with emissions is that intakes get sooty and so do egr coolers. Need to clean them every 60 000 - 100 000 miles. Also keep eye on sensors - IMAP, EMAP (exhaust back pressure), dpf differential pressure. If they are more than 5 years old just fit new genuine sensors or keep an eye on their readings. But if IMAP reads top high you can wreck dpf in a day. Even top brand aftermarket sensors are hit and miss. VAG 2.0tdi differential pressure sensors for example - last five I have seen just read incorrectly. Yet all original ones from dealer work perfect. The failure rate for genuine nOx sensors is ONE per two million.

Which 3.0 diesel is yours?

Italian ecodiesel ? Notorious for V valley coolant pipe leak (since scr yours has to be newer, there is no watercooled turbo on early ones !) and swirl flap gear breaking in intake manifold. Absolutely horrible engine repairability wise due to no genuine engine parts available. Aftermarket parts cost a fortune. While aftermarket head gaskets, seals and bolts do work, critical parts like crankshafts DO NOT! Both new engine price and availability is sad and price is way more expensive than 5 years ago.

French 3.0 used on F150? I have one in my engine stand that has snapped crankshaft. Waiting for a month for crankshaft from dealer and no idea when it is going to arrive. Luckily parts are in stock in US.
Will fit new genuine timing chains, new cam dampener, will adapt truck cam dampener to crankshaft and will do vacuum/scavenge oil pump mod (drill small hole so scavenge pump gets constant oil and is able to scavenge oil from turbo return sump all the time). That is if I do get genuine parts to fix it. I have second same engine car with broken passenger side timing chain. Almost 15 year old British luxury off road oriented vehicles that are cheap due to constant issues.

Benz 3.0 v6 2010+ with 15.5:1 compression ratio? Nothing bad to say about those besides newer ones having single row timing chains and worn out cylinder liner coating (no cast or steel liners anymore sadly). Piston ring design is same junk as all newer engines. Oil intake plastic pipes can crack at seam and cause oiling issues. Also oil pump has electrical solenoids. All in all these engines do last if properly maintained, unlike Italian and French counterparts that snap crankshafts and on french case cam gears. Only one of them to have aluminium intake manifolds, rocker covers, oil filter housing.

2016+ 3.0 inline Benz diesel. Quite well refined engine, but higher mileage ones have lower end issue usually due to previous cam/rocker roller failure and nobody pulling sump to replace oil pump. Roller rocker bearings got wiped out in some cases at 60 000 miles. Complicated and time consuming to fix. Lots lots of plastic. Timing chain wear is also common, v6 timing chain lasted way way longer.

VAG 3.0tdi 2012-16 or 16+. Design wise good bottom end. But notorious for sump leaks, coolant leaks (plastic valley flanges), rattling single row timing chains. Later ones have two part spring loaded cam gears that also start rattling, new cams are like 2500 + lots of work. Twinturbo engines have bottom end issues sometimes, usually after tuning... This year I know two instances that had engines fail, both 2016+ cars and both cases were tuned by someone, so can not blame the engine. Both engines failed shortly after tuning and they had 160 000 miles.

Bayerische Motoren Werke 3.0diesel 2013-2016 and 2016+ . Basically same design, crankshafts interchange if you do trigger wheel mod. Both have issues with crankshafts getting curved and wiping out main bearings. Newer ones have low pressure egr and higher rail pressures (HCCI combustion). Plastic rocker covers leak all the time. Same crappy oil ring design and usually start consuming oil at 100 000 miles. Early ones had cracked liners in aluminium block. Usually due to abuse and huge power updates. Engine block cracked between cylinders, liners have dropped too, but uncommon on unmodified well taken care of engines.

Mandated vehicles need regular egr tuneup to keep it working. Also clean out scr doser and inside of exhaust where there is scr buildup from doser. You can try to wash scd doser in ultrasonic cleaner, before replacing it. What about oil change intervals? 10w40 or 15w40 truck oil should be many times cheaper than expensive low saps 0w20 or whatever oil they use on new diesels nowadays. So you should absolutely change it way more often. I change oil on my cars every 5000-10000 miles.

I have used 5w30 instead of 0w20 on newer Volvo 2.0liter diesels. For some reason 5w30 oil is allowed for those engines in the states but not in Europe. I looked up bearing clearances for those Volvos, V6 benz, Inline6 oldschool benz diesel commonrail engines and the bearing oil clearances very very similar - around 0.05mm. Most likely turbos are not fundamentally different design wise so I would not be afraid of them. Maybe on gasoline powered vehicles that have variable valve timing it would not be good idea to use higher viscosity oil. BUT https://static.nhtsa.gov/odi/tsbs/2022/M...8-0001.pdf - for some reason fix for oil solution issues on some gasoline car was from manufacturer to do piston soak and switch over from 0w20 to 5w30 oil. If it were my own car I would use 10w40 and change oil at least every 5000 miles. I did change piston rings on one of those newer 2018 Volvos that had oil consumption issue. After the repair engine will only use 5w30 oil from now on. In few weeks I will get an update about how things have turned out oil consumption wise with new piston rings (still same crappy design with no drain holes even the latest revision rings, no aftermarket ring seemed to have drilled holes either and I was not going to have pistons turned to fit piston rings from other car since it was not my own vehicle). There is another friend with oil consumption issues on 2020 volvo 2.0 diesel, oil consumption is like a quart every 600 miles. Piston ring replacement will be postponed on until I get a spare engine, or cylinder head since the head might be visibly cracked and I am not going to assemble those engines with faulty parts. Piston rings change is like 2-3 days of work and lots of seals, bolts, gaskets required to carry out this job.

You could try to improve things by adding catch can to Positive Crankcase Ventilation system and route oil vapours away from intake. But usually those newer cars have crank case ventilation membranes so there is almost all the time small pressure present in crank case. If it is possible to eliminate try to eliminate so engine could breathe freely and have less oil leaks, oil consumption from turbo and also prolonged engine top end life ( newer Benz especially with roller rocker bearing failures). You do not have to make permanent modifications to do that. You could buy new oil cap and drill a hole there and add a 90 degree elbow and route hoses to catch can. Most cars have room for that, but it is not the visually appealing but is revertable in seconds. PCV membrane is not going to open that way so you should get away without blanking anything. But some oil caps are located in bad place that they get oil sprayed on them, just to keep in mind.

I have been running same gear oil and 10w40 semi synthetic in a 260hp 1.5l supercharged PWC. Engine had spun bearings, crank got ground down 0.25mm under. I rode it 13h this season after the rebuild. Reground crank is not the best idea, but only other option in this case is new engine, which does not make any economic sense on a 15 year old toy where new engine costs more than market value... I will pull apart engine after 50h of riding to take a look at the bearings and see what is going on. Original engine failed due to crappy supercharged rebuild (shaft snapped after rebuild and engine got full of metal debris that was not cleaned out) at 175h. Same engine that is just naturally aspirated lasts 1000h, I have seen few rental PWC s for sale with that big hours and engines happen to be original without any rebuilds with 100h oil change intervals. On my PWC I replace oil after every 3-5h of riding.