Underrated 3 Series: The 325 tds in the E36 – once the fastest diesel

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BMW's 3 Series turns 50 this year and is thus almost the brand's oldest model series. It still best expresses the core of the brand. For a series of articles, we have selected models from different generations that are currently somewhat under the radar when buying a used 3 Series.

Have you felt old today? If not, most 3 Series from the third generation (internally E36, built between 1990 and 2000) can now be registered as classic cars. The design, which was heavily debated at its premiere in autumn 1990, appears timeless and has aged gracefully without seeming quirky today. Diesels did not yet play the later overwhelming role in sales figures. The diesel boom was only just beginning to emerge in the early 1990s. Fiat and Audi already offered direct injection engines, but the real breakthrough in sales figures only began in 1993 with the first VW Golf TDI.

In the same year, BMW added the 2.5-liter inline six-cylinder diesel with an intercooler and a few subtle changes to the engine to the 3 Series program, turning the 325 td into the 325 tds. An excerpt from the E36 brochure shows how long ago that was: “In addition, exceptionally low-emission exhaust gases are produced due to the high air utilization.” Advertising that would be unimaginable today, ten years after the Volkswagen emissions scandal was exposed.

Why the 325 tds?

The 325 tds, even more than the 325 td with 85 kW, gave the third 3 Series some unusual characteristics. With 105 kW, it was one of the fastest diesels on the market at the time. In internal comparison, it offered 260 Nm of torque at only 2200 rpm, which was more than a 325i offered, which was the top model at the time, short of the M3. While the six-cylinder gasoline engines always required a high engine speed to develop their typical flair, the 325 tds easily pulled strongly even at low revs. A 320i needs to be kept at high revs if it is to perform in a typical BMW manner. A 325 tds, on the other hand, seems to effortlessly shake out its power, as long as you stay between about 1700 and 3500 rpm. Below and above that, not much happens. So the operating range wasn't huge. However, the most powerful diesel, with its robust characteristics, along with the 325 td, is the only 3 Series from that era for which I would even remotely consider an automatic transmission.

Its running smoothness was worlds smoother than that of the first TDIs. A pre-chamber diesel builds up its combustion pressure less abruptly compared to a direct injection engine. It took many years of development work until the compression-ignition engines, which inject directly into the combustion chamber without detours, came even close to this running smoothness. The sound of the 325 tds has something calming about it. Contemporary tests repeatedly state that the six-cylinder is barely distinguishable from a gasoline engine after a short warm-up phase. The downside of a pre-chamber diesel is: A 325 tds naturally consumes less fuel than a nominally similarly powerful 320i, but not dramatically so. You can generally expect seven to eight liters of diesel. In return, the 325 tds sprints to 100 km/h in just over ten seconds and reaches a top speed of well over 200 km/h.

What to look out for?

After initial quality problems, the third 3 Series matured into a very solid car. Of course, it is not entirely free of weaknesses. Rust mainly spreads in hidden places, including behind the jack points covered by plastic caps. BMW took good precautions, especially in the later model years, but door edges, wheel arches, and the sheet metal around the handle strip on the trunk are typical areas where many E36s rust.

The actuators for the central locking system are prone to failure; replacing them, especially in the rear, is a bit fiddly. The control unit for the automatic climate control frequently breaks down. Do not buy a new one, but have the existing one repaired by specialists. Only at the last moment does it seem that someone during the E36 development came up with the idea of equipping the ventilation system with a microfilter. It is installed in the interior at the bulkhead; to replace it, the glove compartment and everything behind it must be removed. The time allocated for a complete replacement was four working units, i.e., 20 minutes – only the top performers managed that.

A classic problem is the quickly worn-out guide joints in the wishbones, which are simply undersized. In my father's E36, they needed replacing after 23,000 km while still under warranty. BMW replaced them individually with a small puller; many independent workshops have likely since switched to simply replacing the entire wishbones.

Especially the later model years of the E36 are fundamentally very mature and solid cars that can achieve very high mileages with a little care. From 1997 onwards, BMW stabilized the slowly declining sales figures with extensively equipped special models, which in some cases made the 3 Series very luxurious. Air conditioning was not standard equipment until the end, but given the large cockpit landscape behind the flat windshield, it is one of the important extras. The multi-adjustable sports seats are very comfortable, but they were rarely ordered.

Market situation

Describing the current availability of 325 td and 325 tds as “limited” would be a gross understatement. The E36 diesels are not rare; they have practically completely disappeared. There are several reasons for this: fuel consumption, performance, and the running smoothness of the diesels of that time were soon surpassed. The compression-ignition engines were primarily bought by people who covered high annual mileages. There may still be hidden garage treasures among the E36 gasoline models, but the chance of finding a 325 tds with low mileage and in good condition is almost zero. They were used for hard work and simply worn out. In addition, the 325 tds came onto the market with the Euro 1 emissions standard; only from 1996 did it meet Euro 2. Depending on the model year, between 400 and just under 700 euros would be due for vehicle tax alone today.

(mfz)