After completing the bodywork on Big Apple, I wasn’t in a rush to apply the paint but instead began working on the engine and chassis. The chassis of 140.043 was far from being truly fresh, so it’s the engine rebuild of its 119.981 that gets recorded here. I initially thought this would be a straightforward task, but, as usual, I was wrong.
The known history of Big Apple’s engine is as follows: the last recorded service was at 36,765 miles on September 7, 2001, which was very close to its unfortunate end. Afterward, it was reported as a total loss. When it received a rebuilt title on May 17, 2002, the odometer read “9,” which may have been a mistake. Afterward, between 2002 and 2023, there were no records until I got it, with the odometer reading 139,666 miles. I lean towards this being the actual mileage.
The car was imported into China in March 2007 and sold to a 59-year-old lady. Before that, there were no records from 2002 in the U.S., suggesting it wasn’t registered or driven at all. It seems reasonable that it would have traveled 100,000 miles in the 16 years of ownership in China. Moreover, although it’s hard to find accurate mileage on used cars here, dealers often tamper with the readings, typically lowering them to between 180k-230k kilometers, with well-maintained ones sometimes showing 90k. Since most people here don’t fully understand mileage units, a reading of 140k would seem unusually low for such a poor car.
140,000 miles – some people would say that’s just the warm-up for these “bulletproof” M119 engines. But to be honest, I’m not familiar with the M119. I’ve only heard from mechanics around me that the M113 is undisputed, while the M119 isn’t the best. During the test drive before the rebuild, we did notice the engine light on, but HHT indicated it was just an oxygen sensor issue. The idle was very smooth, and there was no unusual noise while ideling. I almost skipped the engine rebuild entirely. But I chose the 140.043 as the long-haul travel option: it had the same low cruising RPM as the 5-speed V12, balancing performance and efficiency. I didn’t want to skip anything and risk needing a tow 2,000 km away with my family.
If the cylinders passed the endoscopic inspection – with no ridge on the cylinder walls – I would have stopped at just the head gasket replacement and left the crankcase untouched. I was confident about this, as 140k miles didn’t seem like much. However, unfortunately, the endoscope revealed that at least two cylinders had noticeable scratch on the walls. This is the issue with strong Mercedes engines: when you’re behind the wheel, everything feels fine, but you might just be driving a cancer patient. You can keep believing in your senses and ignore it all, but don’t cry the day it suddenly dies. Or just take it through a tough treatment, but it might still not survive.
Symptoms
During the test drive, Big Apple showed no major issues, and there was no visible oil consumption even when started in winter. But the engine’s problems only became apparent as I began disassembling it. Before starting the rebuild, I noticed oil sludge and carbon buildup on the cylinder head through the oil filler cap, but I didn’t expect it to be as bad as it was once I removed the valve covers. The bolt recesses on the cylinder head were completely filled with sludge. The valve seats had carbon deposits stuck to them so badly that they were essentially buried.
This is unpleasant, but understandable for a car that had been in service in Guangdong for 16 years. Very few Mercedes owners in that area go to the dealer for maintenance, and many don’t maintain their cars at all, with some even avoiding maintenance altogether. There’s also a lot of counterfeit and fake products, and when people complain about Chinese-made fakes, they’re often talking about products from Guangdong, which is where most counterfeit goods come from. Perhaps this car had been harmed by fake motor oil or a greedy repair shop.
After all, sludge is only part of the disaster, some even more reckless repair measures were evident. The oil seemed to have been diluted with diesel to loosen the sludge, making it sticky. It did some good but could have ruined everything. There was some ice-crusted debris in the cylinder head—large chunks of carbon deposit that could easily fall off with a bit of force. It seems that such carbon buildup had fallen into the combustion chamber through the valves, leading to the cylinder wall damage.
There were also corrosive agents that had been added to break down the sludge, and upon inspecting the camshaft and cylinder head mating surfaces, they had been severely corroded. Btw one of the cylinder heads isn’t original. One was marked as being produced in January 1997, fitting the car’s period, while the other was produced in January 1996, which was too early. This one had been replaced. Even though one of the cylinder heads had been replaced, it had still ended up in this sorry state. What exactly had happened to this car?
Upon disassembling the crankcase, I found that three pistons and cylinder walls had severe wear, and one connecting rod bearing was badly worn. Given the non-factory markings on the pistons and connecting rods, along with the widespread use of sealant instead of gaskets, it is clear that the engine had likely been rebuilt (or butchered) at least once before. As for the broken valve cover gasket, spark plugs soaked in oil—these seemed trivial in comparison. Could this car’s actual mileage be 140,000 miles?
At this point, history perhaps no longer matters. I quickly realized this was going to be a hassle, but there was no turning back. Since I hadn’t worked extensively on the M119 before, I decided to go ahead and do everything, and do it right. We should ensure that each restoration project teaches us something new, and apply new techniques to achieve eternal progress compared to the last job.
Methodology
During the disassembly, I became familiar with the structure of the 119.981, which should be similar to the 119.980 and the earlier 119.97x variants. The differences with the M104 and M120 are as follows:
1. Cooling Intake Manifold
The intake manifold on the M119 is part of the cooling system, with coolant flowing through the front and rear sections of the manifold, so sealing and isolation must be carefully managed during assembly.
2. Timing Cover
The front timing cover touches the cylinder head, meaning if the cover is removed, the exposed gasket needs to be replaced, which is a maintenance nuisance.
3. Exposed Alloy
Since 05/93, the M119 has been almost entirely made from bare aluminum, with no protective coating other than factory wax. This exposes the engine to oxidation quite easily.
Overall, the M119 is more compact and simpler in design compared to the M104 and M120. The saying that a V8 is simply two 4-cylinders makes sense, as it appears that the engineering complexity of the M119 is indeed lower than that of the inline-six. This is reflected in MB aftersales’ pricing for the new long engine blocks: the M104 and M119 are similarly, while the M120 is three times more expensive. The compact structure and fewer parts make assembly more complex, requiring strict attention to the order of assembly and careful sealing and isolation of the water, oil, and air passages. These are actually sealed by the gaps in some die-cast components, almost as if constructing a water pipe capable of withstanding 3 bar pressure out of LEGOs.
The most troublesome aspect is probably the pistons. Worn cylinders can be remedied by replacing the cylinder sleeves, but the pistons can only be bought new. The problem is that Mercedes-Benz has already discontinued all three piston variants, and the supplier KS KOLBENSCHMIDT no longer offers them. Currently, there are no new old-stock (NOS) pistons available anywhere in the world. Perhaps we should realize that the updated 4.2 liter M119 was used for only three (in reality, two) model years in the W140, with the only other application being the 1997 E 420. Who would replace the pistons in these engines? They may never be available again.
I initially planned to spend a month finishing the engine, but now that timeline has stretched to nearly endless. The 140.04x is the best-selling model in the North American market, yet it is very rare elsewhere. In China, where I am based, I have only seen four 97-99 S 420s, with Big Apple being one of them. Purchasing parts is no longer an option, and the hope of finding a donor car is slim. I was feeling very frustrated, but then a month ago, I remembered a sales listing I had seen. The seller had misclassified a V8 W140 as a “1989 S 500” — a North American 97 model. I went back to the listing, confirmed its configuration, and found it was indeed a 1997 S 420, with a production period very close to Big Apple’s.
The car once belonged to a former nightclub owner and was parked alongside other vehicles in a lot after the club shut down in 2013—abandoned and left to time. The owner has now decided to part ways with the entire lot of vehicles. Carfax shows it is a real runner! Originally registered in Boise, Idaho in May 1997, it had already clocked 33,000 miles by December 1998. By July 1999, it had 62,000 miles! By the time it was exported in September 2003, it had accumulated 144,000 miles in just six years.
I was truly worried about the engine, but as long as I could obtain three pistons without scratches, I would be satisfied. One day later, I received the express. Surprisingly and unsurprisingly, it had undergone an engine swap. The current engine is a 119.985 sourced from a 1997 E 420 and appears to be in decent condition. It’s essentially the same as the original 119.981 found in the S 420. Since we only plan to use the pistons, the difference is negligible. I’m not a W210 specialist, so I couldn’t identify which E 420 it came from, but I suspect it might have been from Japan.
I had already spent considerable time cleaning the cylinder heads, but since this engine was in such ideal condition, I decided to simply rebuild the 119.985 and modify it into a 119.981. Honestly, during the disassembly, I didn’t find any real difference between the 119.981 and 119.985, except for variations in fasteners due to production cycles. Perhaps this engine had already been adapted in the previous swap. Upon disassembly, I discovered that this 119.985 was completely untouched, with only the valve cover having been once removed, everything else was pristine. Naturally, there was no abnormal wear—this was truly an ideal project.
To address the engine’s special appearance, I finally procured a piece of equipment I had been eyeing for some time: a vibratory polishing tank. Its principle is similar to those used for polishing aluminum wheels, where abrasives are tumbled to polish metal parts. The alloy components of both engines had suffered significant oxidation in the environment, which had to be removed and restored to their factory luster. In the past, a common approach for cast aluminum was to use faux metallic paint, but this was far from ideal for an engine that was entirely presented in cast aluminum gloss. We will restore the shine and then apply clear varnish to seal it for durability.
Highlights
Parts Ordering
In order to save time, I began ordering parts more than a year in advance. Many parts for the 119.981 are still available, so we encountered no major obstacles in this regard. It is important to note that some seals for the 119.98x are slightly different from those for the 119.97x. If a complete Victor Reinz repair kit is not available, one car order parts specific to the 119.98x and combine them with those for the 119.97x. Since most 119.98x repair kits on the market are for the 5.0 liter 119.980, I specifically ordered the cylinder gasket, which is the only difference between the 119.980 and 119.981 kits.
Further exploration of the engine also led to a change in the quality of some parts we order. During disassembly, I learned that the water pump of the M119 is almost the last component to be removed from the front of the engine. Replacing it requires dismantling everything at the front, so it is wise to choose the most durable parts. As such, I ordered an original remanufactured water pump to replace the 28-year-old original pump. In some markets, the old pump can offset $65 as a core charge, but I’m curious if they can really remanufacture ours. Even though the aluminum housing seems irreparable, the water pump I received is essentially brand new.
Over the past year, as the definition of Big Apple has evolved—from a quick correction project to a reliable long-distance cruiser—and as plans have been continually delayed (there’s never enough time), more funds have been allocated for rapid, long-term solutions. I’ve sourced a remanufactured 143A alternator (discontinued but periodlu correct, not the replacement 150A version), a new genuine AC compressor, starter, ignition coils, fuel lines, and all parts that will guarantee the next 50,000 miles.
Neither MB Genuine nor other suppliers offer a rebuild kit for the late M119 power steering pump. However, it is identical to the ZF pump used in some 90s BMWs. The pump features a unique imperial-sized main seal, which is not readily available. Fortunately, the BMW rebuild kit 3241-1135-880 provides an excellent substitute for this component. Write that down, fellows.
Cast Aluminum Restoration
Restored classics are usually more fragile than when they left the factory, especially if their original appearance is preserved. Our challenge, therefore, was to achieve factory-correct aesthetics while delivering greater durability. As a full-alloy V8, every surface exposed to the elements underwent vibration polishing, magnetic polishing, a deep precision cleanse, and finally a barely perceptible high-temperature transparent coating.
As of May 1993, the M119 valve covers were left as bare alloy. This is quite unique within the S-Klasse lineup—while both the inline-six and V12 have coated valve covers, the V8’s coating was discontinued midway. To slow oxidation, protective wax was applied at the factory. However, the unsightly yellow wax eventually degraded, causing oxidation spots to form on the valve covers, gradually darkening them completely.
Conventional restoration methods are ineffective for this issue, so I invested the vibratory polishing tank specifically for the task. The process starts with wet blasting to remove oxidation, followed by vibratory polishing with an aluminum-specific compound. But that alone is not enough—since long-term oxidation resistance is crucial (and chemical passivation is unreliable), I applied a VHT clear ceramic coating. With this, I can now confidently enjoy the vehicle in any environment. Past solutions involving silver paint simply couldn’t match the original texture or durability.
The cast iron exhaust manifolds are restored in the same way. This not only renders the engine’s exterior fully oxidation-resistant but also dramatically improves cleanability: even aggressive detergents can be used for quick cleaning without removing the engine and without dulling the alloy’s natural luster.
Crankcase Inspection
The cylinder numbering of the M119 is different from the M120. The coneventional right side (passenger side for LHD cars) has cylinder 1 at the front, in contrast to the M120, which is axially symmetrical. In the two engines that were disassembled, one had numeric markings on the connecting rods, while the other did not. If no markings are present, it’s best to label them. Before sending the parts to a specialist shop for measurements and cleaning, I made sure to explain the cylinder numbering arrangement to ensure they wouldn’t mismatched the pistons and cylinders. This layout was unfamiliar to the shop, so the explanation made sense.
The timing check is also quite unique. The camshaft gears align with the holes in the front camshaft cap when the pointer on the water pump is pointing at the crankshaft’s vibration damper at 45°. This isn’t the TDC or BDC of any cylinder but a setup that ensures all pistons are centered, leaving a gap between the pistons and valves when installing the cylinder head. If the chain needs to be replaced, remember to mark the number of chain links between the two camshafts before disassembly.
Although the endoscope inspection showed that the donor engine was in perfect condition, I decided to fully disassemble it for a thorough inspection, as it was a great opportunity. Moreover, during the disassembly of the first engine, I noticed carbon buildup on the piston rings, especially on the oil control rings, where the carbon buildup was unusually harden. It was best to remove and clean them. Therefore, every part of the crankcase was disassembled and sent to a professional shop for pre-cleaning. We then conducted another round of deep cleaning for the pre-cleaned parts. The gaps between the crankshaft and pistons, as well as the bolt lengths, were measured, all of which were very close to the standard values.
Installation of the Front Timing Cover
Unlike the M104 and M120, the M119 cylinder head doesn’t have two separate timing covers. Instead, it follows the traditional V8 design, where the chain is directly inserted into the cylinder head. The front part of the cylinder head itself serves as part of the timing cover. Thus, after removing the lower front timing cover, the front part of the cylinder head gasket will be exposed.
According to the WIS, removing the front timing cover does not affect the cylinder head or cylinder gasket. This scenario applies when replacing chain guides or the front crankshaft seal. In theory, you can just reassemble the timing cover without worrying about the gasket’s condition when the engine is healthy. However, after nearly 30 years of use, the cylinder gasket has bonded to the metal, and disassembly lead to a loss of sealing effectiveness.
We were not particularly concerned about the gasket, as it would need to be replaced during such an extensive job. The real concern was when to install the front cover. The WIS recommends doing it after installing the cylinder heads, but during disassembly, we discovered this process was quite tricky. After placing the cylinder head, the front cover needs to be slid in from the front to the back. This involves three main steps: 1. Inserting the locating pins. 2. Extracting the chain. 3. Avoiding compression of the cylinder gasket. The third step is probably the riskiest.
Considering that the cylinder head bolts shouldn’t be tightened too many times, and tightening them is not easy, if we found the front cover couldn’t be slide in after the cylinder heads were in place, it would waste both parts and time. Therefore, to play it safe, we decided to install the front cover first, then the cylinder gasket, followed by the cylinder heads. This way, the front part of the gasket would naturally be pressed against the front cover by the cylinder head. It’s also important to pre-install the water pump and crank the crankshaft to 45°, as it would be difficult to crank it later after installing the lower chain guide. Additionally, I still recommend not neglecting the gasket during future front cover maintenance. This can be quite a headache.
Assembly Sequence
Like it or not, the M119 is the shortest and lowest of the three gasoline engines in the W140 line up. This is due to two factors: firstly, the 90-degree angle means the V8 is lower than the V12. Secondly, there’s a legacy of the M119’s original CIS KE-Jetronic system, which led to the air filter being placed on top, forcing a reduction in the height of the engine block. The M104, with its HFM-SFI system, moved the air filter to the side in 1993, but the M119 did not. Fitting the same number of components within a more compact vertical height and longitudinal length leads to a very cramped engine bay.
For example, the water pump is located behind the crankshaft pulley, the throttle body is at the top of the crankcase, and the knock sensors are inside the engine mounts. If you need to replace or inspect any of these, you’re in for a challenge. As a North American car equipped with EGR, the pump also blocks the path to the thermostat. To remove the thermostat, the EGR pump must be removed, which might require removing the oil filter housing. The timing cover itself is only connected to the cylinder block with four bolts. To achieve the best seal, it’s best to apply sealant and install the timing cover, water pump, AC compressor bracket, and belt tensioner bolts all at once.
Thus, the installation sequence for the following components is almost fixed:
- Crankshaft – Pistons – Oil Pump and Chain – Timing Chain – Chain Guides – Timing Cover – Water Pump – Belt Tensioner – AC Compressor Bracket.
- Crankshaft Pulley – Oil Pan – Flywheel – Cylinder Head – Camshafts – Timing Guides – Camshaft Caps – Valve Covers.
- Oil Dipstick – Exhaust Gas Pump Pipes – Oil Filter Housing – Exhaust Gas Pump Bracket – Exhaust Gas Pump.
Other components like the flywheel, alternator, and power steering pump can be inserted in a relatively random order.
Although the M119 leaves the most longitudinal space in the engine bay, it’s essentially useless. Every single component is interdependent. Other engines allow for more independent parts. The work on the M119 is far more complicated compared to the M104 and M120, with only a few easy tasks, such as the exhaust manifold being secured with bolts instead of nuts, making removal and installation somewhat easier.
Summary
Over the past three months, Big Apple’s 119.981 has been completely rebuilt. As this year’s signature project, Big Apple’s powertrain has received more upgrades than previous undertakings. Every task has aligned with the central objective: to be reborn in the warmest environment and to survive in the harshest. The intended environment for this car is snow. That’s part of a plan for next year—a journey I look forward to taking with my family.
Thanks to dedicated observation and a bit of luck, this unavoidable M119 rebuild has effectively averted the crisis. The simple ME-Motronic system is a good start for the M119 series, and the project wasn’t hindered by part supply issues, which helped in gaining a preliminary understanding of the M119’s characteristics. Next, I will continue exploring the more complex LH-Jetronic system, which will be a next-level test, especially in terms of parts collection.
Here’s some after and before of this restoraton:
