Personal experience: how to change the engine in a car and not be left with nothing

You won't believe it, but on that sunny March day when the OM642 diesel engine in the 2013 Mercedes ML with only 157 thousand kilometers on the clock kicked in, the author had a sneaky thought while driving: what a wonderful car! In nine years of ownership, I only had to change consumables and brake discs at 110 thousand kilometers. Everything else was in its factory, untouched by repairs.

True, the main part of the run was on the smooth Kiev highway, the author never killed the car on trophy raids, passed maintenance on time, and in between he also did some NON-collective farm tuning, replacing the standard body kit of bumpers and fenders with an original ML63 AMG, a radiator grille in the style of "Maybach" and taillights with reinforced LEDs from a later modification of the GLE. Of course, the leather interior with perforated brown nappa migrated from the ML63, and the Harman Kardon acoustics, and the multimedia from the GLE...

Well, how can you not step on the gas from a traffic light, experiencing a slight kickdown, with such a wonderful outfit, and even on new 21-inch AMG wheels?

He stepped on the gas. His boot hit the floor, and in response… The car jerked its nose and stalled. And only his wits made the driver, using the momentum of the movement, change from the left lane to the right, so as not to end up motionless in the middle of Leninsky Prospekt.

And then the life of the Mercedes car enthusiast was painted in heavy noir and minor. At the service station, without even unloading the car from the tow truck, the service manager with 95% confidence pronounced the verdict:

— The death of the crankshaft occurred as a result of oil starvation...

- Have mercy, why? There were no visible symptoms.

“Nobody knows this until we send the engine for defect detection, disassemble it and see the cause,” the master noted philosophically. But then he added:

— Defect detection and repair will be expensive. About 600 thousand for work and spare parts for a million and a half. They are now gold. Or platinum…

You don't have to go far for examples. Just type in the price of one original crankshaft on the German spare parts website. The result was shocking: the piece of iron cost 230 thousand rubles! And its delivery time was 60-70 days. And a whole bunch of such pieces of iron for the engine were needed, not counting the gaskets and sensors. No matter how you look at it, the engine overhaul cost two million rubles and there was still the question of whether it would be done well. Even the auto repair shop mechanic wasn't 100% sure of that. So the honest man gave a blunt recommendation:

— Buy ​​a contract engine - we will deliver it!

Selling your favorite car for next to nothing was clearly not an option. Buying a new one for 15 million was out of the question. Surrendering to Chinese dealers? No thanks… And so the author began to study the topic of contract engines.

And in this field, an unpleasant surprise awaited him. The entire automotive community, like adherents of faith, was divided into two parts. Some, the skeptics, insisted that it was impossible to buy a perfect engine in Russia. Under the guise of one coming from abroad, they would palm off a unit assembled in the Russian Federation from shit and sticks. Or the engines that arrived would be no better than those already killed in their homeland. Evidence of this are hundreds of videos on social networks and YouTube, where "contractors" turn out to be worse than dead units.

Optimists, on the contrary, say and write that everything is not as bad as the messengers of the apocalypse say. If you choose an engine together with a master of his craft, if you inspect the cylinders with an endoscope, if you install it correctly, then there will be no grief. Your car will run like new and will run for many years, while the skeptics suffer on new Chinese analogues.

The well-developed contract engine market also speaks in favor of this version. Just type the corresponding request into Yandex and you will get such a wealth of options that it will take your breath away. It seems that the entire auto service industry does nothing but replace jammed engines with still usable ones.

But from the very beginning of the search it is worth understanding that chasing cheapness is a dead end of time and money. A serviceman I know said so:

— You don’t even have to look at anything that’s cheaper than 700 thousand rubles.

Although numerous dealers offer more than tempting options. For example, a power unit for the S-class for only 117 thousand rubles.

However, upon closer inspection it turns out that the price does not include attachments, which may cost more than a block with cylinders. And the appearance of cheap motors indicates that the unit did not come from an insurance company warehouse, but from a junkyard for dismantling cars subject to recycling.

However, he who seeks will always find. And we found a company that has been dealing only with Mercedes engines for 20 years and buys them from European insurance companies that sell parts of damaged cars with known mileage. At the same time, as the dealers assured, not all units are sold. If, say, the impact was in the front part of the car, then the engine is scrapped.

Sounds tempting. And the offered engine looked quite decent. No traces of repairs, all stickers were fresh, factory, gaskets too. The endoscope showed the ideal condition of the cylinders, and according to the documents, the mileage since 2018 was 52 thousand kilometers.

As a result, after three days of waiting and 920 thousand rubles, the power unit took its place under the hood with a three-month warranty.

Is that all? A happy ending for the old Mercedes and its owner?

Sometimes our car service as an industry as a whole resembles a snake that eats itself, in the sense that it is infected with shoddy work and elementary deception. In such a complex matter as engine replacement, this generic disease, of course, could not help but manifest itself in our case.

From the first day, the new engine started worse than the old one. That is, not immediately, not with half a turn of the starter, but after a series of scrolls. When asked why this was so, the installers answered that air got into the injectors and therefore it was necessary to drive for some time until it completely went away.

Four months later and after the warranty expired, the air still hadn't gone anywhere, so I decided to ask another service about the causes of the defect.

"Air has nothing to do with it," the mechanic concluded. "Your engine is not from your model. The camshaft sensors are set for the S-class."

And this means that the sensors need to be changed and the new engine needs to be reconfigured for the old program. No sooner said than done. But in the process, a truly monstrous thing was discovered: the engine is pumping oil into the turbine, the oil cooler gasket is also leaking, and the crankshaft seal has become completely worn out!

To fix all the flaws and oil loss, which leads to the inevitable death of the new engine, it must be seriously disassembled, including removing the automatic transmission (otherwise you won’t be able to get to the crankshaft oil seal!).

Presenting hefty bills for the work, the servicemen were perplexed with all their hearts: why didn't the engine installers do all this? After all, this is the basics of this operation. After all, it is clear to a horse that a contract engine can lie around in warehouses for a year and during this time its gaskets and seals simply dry out, requiring replacement.

Unfortunately, these are rhetorical questions.

And you can also console yourself that not all the oil in the new engine leaked out, that it turned out to be original oil, and not a fake liquid in pretty cans, because of which half of the engines in foreign cars are doomed to premature death.

As for the new engine, it's great. Quiet. Fast. Beautiful…