Buying a used diesel engine (Opel Omega B)

Be careful when buying a used diesel. Diesels last a long time, but that doesn't mean you shouldn't inspect all the traditional wear areas. On some engines, it's very easy to disguise both the age and wear. There's a risk of "mistaking" the condition of such an engine if you don't know much about diesels.

Like petrol engines, diesel exhaust should be smokeless. In addition, there should be no smoke coming out of the open neck of the oil filler tube on a warm engine. Since diesel engines are noisier than petrol engines, you should distinguish between operating noise and the knocking of worn pistons, connecting rods, camshafts, etc. If you have any doubts about the condition of the engine, seek help from professionals.

Turbodiesels are very popular because turbocharging fits well with diesel engine characteristics. Turbochargers operate at low boost pressure and low engine speeds, which gives them a longer service life than gasoline engines. Turbodiesels are excellent for tractors and multi-ton trucks.

However, diesel automatics have a hard time meeting the demands of an automatic transmission due to the flat torque curve. Only a few manufacturers are concerned about this problem. Among them are Citroen, Mercedes, Peugeot and the recently joined Opel, but even then they only use automatic transmissions in mid-size cars.

Thanks to their ever-increasing popularity, diesels are no longer seen as the poor cousin, and are now fully on par with their petrol counterparts in terms of trim level.



When buying, pay attention to the residual value of diesel. Diesel cars once gave impetus to the growth of car sales in Germany, but sales peaked four years ago and have been gradually declining to this day, so make sure you are not overpaying for the privilege of owning a diesel car.

Check the mileage. Diesel cars are bought for their potential for high reliability and potentially high mileage. Especially when they are bought new. But this does not mean that you should not pay attention to the odometer. Indeed, many dealers do not like to deal with cars whose mileage has exceeded 80 thousand km and, accordingly, adjust the price on them. Or, without further ado, simply reset the mileage on the odometer. A mileage of 160 thousand km is quite normal for a well-maintained diesel, but think twice if the meter shows 320 thousand km or, especially, if it is a used taxi with such a mileage.

With the exception of the engine, most diesel cars are identical in design to their petrol counterparts, the same applies to suspensions, brakes, but consider the prices of spare parts. For example, exhaust systems last a long time, but differ from similar petrol engines. And if you are used to buying spare parts from car dismantlers, then keep in mind that petrol engine parts may be similar in appearance and fit in size, but the diesel cylinder block differs from a similar block of a petrol engine and in most cases cannot be selected as a replacement. Gear ratios of gearboxes and clutches also differ.