Just looking for any general information. I’m 19 and just looking to learn more about cars.

 

How many miles? Odds are that you will need to learn and spend way more than you ever wanted. If you are on a budget, get rid of it quickly. Someone may buy it for the engine alone since the engines are known to fail. Running OM642 engines can be quite valuable.

 

Learn to post the year of your car as you're in the wrong forum You have a w163 or w164, but we have no way of knowing without your year.

 

While I completely concur that maintaining an older, premium car is going to cost the OP a fair bit more than a newer Honda Civic or a Toyota Corolla both because of the age of the car and the fact that it is a Mercedes, I would disagree with the generalization that OM642 engines are known to fail. The OM642 is a workhorse that has been around for 15 years and is still used in various Dodge, Freightliner and Sprinter trucks and vans today, and has been installed in millions of (mostly) Mercedes, Jeep and Chrysler cars and SUVs worldwide. I am willing to bet that OM642 engine failure rates per km / mile driven are in fact lower than those in most passenger vehicle.

Having said that, it's not the engine per se I'd be worried about - it's the overall cost of keeping a 10-15 year old Mercedes on the road where everything on it is now reaching the end of its useful life in short order and is going to cost a lot of money in various repairs.

 

BTW- this is the wrong forum for the ML320. You need to ask in the W163 / W164 forums.

 

I would take that bet if we are talking about passenger vehicle applications. The OM642 has been a disaster in MB SUV's and much worse when saddled with emissions. By far, the diesel variant is much less reliable in passenger vehicles than their gas counterparts and requires way more money to maintain. In addition, the OM642 in commercial applications, from what I understand, has larger oil passages which seems to make a huge difference in reducing the number of failed crank bearings and possibly leading to better reliability. Let me say this, the local MB dealership more than doubled it's shop size just so they could handle the influx of OM642's and their numerous mechanical opportunities.

Jeep used the engine for a short time before ditching it. MB only uses in the Sprinter and not in any new passenger vehicles.

For a data point, my GL450 with over 250k miles has been great and required very little in terms of repairs. The radiator developed a crack in the plastic side tanks after almost 13 years of ownership and the engine has only required a spark plug change to continue running. It won't last forever but, for now, requires only fluid changes and doesn't even need oil between the 10k mile change intervals.

Do a search for failed OM642's across all forums. The number of failures and mechanical issues will surprise you. I noticed the issues over a decade ago and was flamed for shining a light on the problems and questioning the mighty diesel. Most of those who flamed have suffered the same failure points that were noted a decade back.

 

Aside from the emission component foibles and the oil cooler gaskets that start to leak (both of which are technically external to the engine), 99% of all issues with the OM642 are due to them being driven "for economy / comfort", which is almost always the case in all passenger vehicles. Diesel is a dirty fuel and all the crap stays and builds up inside the engine unless you blow it out and/or burn it off.

I don't need to do a search - I am getting first-hand information from the head tech at Mercedes Canada who is a very good friend and has access to all MB / MBNA data including various failure and service stats. Again, almost all of the observed engine failures are in passenger vehicles that are driven "like a grandma". So - while there is some truth in your statement, it needs to be taken in context. I agree that the OM642 engine is perhaps the wrong choice for passenger vehicles in North America because of our driving culture and habits, but for vehicles where they are often properly exercised (as in regularly "pushed" whether they are loaded or simply being floored when accelerating to pass someone like they do in Europe), the OM642 as an engine is definitely more reliable per KMs driven than the gasoline counterparts.

 

Another one-post wonder.....

 

There is no possible way with the OM642 in passenger vehicles when you maintain per factory specifications. Again, the OM642 in MB SUV's has way too many issues for this ever to be true. The oil cooler seals and timing chains are known to fail frequently as is the emissions system in the Bluetec versions. Oil sludging cause passageways to get clogged and lead to engine failure from spun bearings. Even if you only had oil cooler seal failure which, by the way, are guaranteed to fail, the engine can lose all the oil and, since the oil level sensors will most likely be sludged, the engine will seize without warning. Now, remove the emissions and you will still have timing chain failure, oil cooler seals, and spun crank bearings from oil starvation. Sorry, the OM642 in MB SUV's was a disaster and the number of failures speak to this.

 

I think the key of your argument here is the "... in passenger vehicles when you maintain per factory specifications" part. If you only change the oil as infrequently as the BS Mercedes peddled to their US customers, then you are correct - but not because of issues with the engine.

Yes, the oil cooler seals and the emission after-treatment components fail - but as I said earlier, they are not part of the engine. The reports you may have read of oil sludging are not problems with the engine - they are problems with lack of proper maintenance (specifically oil changes). Regarding the timing chain failures, even the earlier OM642 engines with the double-row timing chains suffered ~10x fewer timing chain failures than the M272 & M273 engines with their balance shaft and idle gear issues, and the later OM642s with the single-row timing chain are even more reliable and again way ahead of the M276 or M278 engines which easily suffer ~5x as many timing chain issues, not to mention oil pump failures and scored blocks. And, unlike with the gas engines, pretty much all OM642 timing chain failures and/or spun crank bearing scan be attributed to infrequent oil change intervals.

As I said earlier, I completely agree with you that the OM642 is not the best engine choice for passenger vehicles in the North American market and in particular in the USA because of (a) our driving habits, (b) extremely unrealistic maintenance expectations (like doing oil changes every 16,000 km - on a diesel to boot), and last but certainly not least, (c) the high (>B5) biodiesel content in the USA which results in the corn syrup (er, biodiesel) ending up in the oil and diluting it during every DPF regen cycle as it can't evaporate the way normal diesel does. However, I maintain that the issues you've brought up are NOT indicative of problems with the OM642 engine design - they are problems because of inadequate maintenance. 86% of all MLs sold in Canada were diesels, but because we don't have the high biodiesel content that you do in the US, we don't have anywhere near the number of problems that you do south of the border. Mercedes certainly deserves the blame for specifying unrealistic oil change intervals and for not explicitly warning their US customers that their government-mandated corn farming subsidies unfortunately means that they'll have to change their oil twice as often as they do if they want their SUVs to last, but the design and reliability of the OM642 motor itself is second to none. If you want more evidence, Google "OM642 engine issues" and then repeat for the other other engines, or just see what motorreviewer.com says about them.

In other words, if you drive it like a grandma and only follow the minimum service intervals, you are indeed going to have problems. If you change the oil ever 5-8K kms and properly exercise it now and then, that OM642 will on average last you twice as long as any other engine ever fitted in an ML or GL and will never experience any internal problems.

 

@MelllyBo T

Well the 'ol' should I keep my ML320 CDI 4matic???

I have had 2 of these, the first died on the highway from Calif to Florida, transmission problems. The same car died on the highway again on the way back, drive shaft problems this time. It was a wake up call and after $10k it was an expensive trip. Dumped the vehicle quick after that as the drive train was going again.
The second CDi died from New York to Texas, and as usual on the highway at night no-one around for miles, $4k later found a used engine had it installed from a local mechanic in Springfield MS. He was a great mechanic did it all one one day, no waiting, took him to dinner afterwards to thank him.
After a friend introduced me to the Jeep Liberty, (that is also built by Daimler) I bought one, loved it, then i bought 2 of them. I was 37 years old then and I must say the jeep was more reliable and far cheaper and easier to repair.
I'm not dumping on my old Cdi, but if i was to buy another one today, I'd buy a 2016 one and nothing earlier because what I've experienced with other CDi drivers is an older CDi is wasting your money.
Sadly, I never listened then, but I wished I had, as I could have saved a heck of a lot of money in my early years. So I have two Jeep Liberty's (2002/2008) a Volksvagon Touring van and a 2018 Cdi.
NOTE: the first year with the CDi was a deal breaker as I only had to fix a fuel pump and new brakes, but if anything major pops up again it's gone!
(Just my 2cents)

 

3 years later and we are still in the wrong forum...