Underrated 3 Series: The BMW 318is – the M3 for the common man

Contents

BMW's 3 Series is celebrating its 50th anniversary this year and is thus almost the brand's oldest model series. It still expresses the core of the brand perhaps the best. 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.

The second 3 Series generation still captures many hearts, likely because all subsequent models appeared much bulkier visually. In the run-up to this article, there was a lively debate in the editorial office about which engine in the 3 Series, internally called E30, was underestimated. There were several candidates, including the "Italian M3" 320iS, the 325e with its high-torque six-cylinder, and finally the 318is, which was only added to the E30 program late and ultimately won by a narrow margin. Strictly speaking, it's not a secret tip, but it is one of the best engines in this model series.

Why the 318is?

The 318is clearly stands out in terms of performance not only from the two-valve four-cylinders but also from the 320i. Although its maximum torque of 172 Nm is only available at 4600/min, it feels significantly more lively between 1500 and 3500/min than the six-cylinders, without being sluggish at higher revs. It doesn't sound as good as the six-cylinder and runs a bit rougher than the M40 four-cylinders in the 316i and 318i. However, it has noticeably more power in all situations without consuming significantly more.

In practice, it might be half a liter per 100 km more than in the 318i, if at all, and considering its better performance, that's a fair trade-off. The 320i appears downright thirsty in direct comparison, especially if it's supposed to keep up with the 318is. With eight to nine liters, the four-valve engine in the 318is is already driven briskly. For the standards of the time, the engine thus combines moderate consumption, high solidity, acceptable running smoothness, and brisk performance. It's hard to combine all of this more skillfully in the E30.

Compared to the tamer four-cylinders, the standard equipment was also sharpened: sports suspension with slight lowering, disc brakes, and a stabilizer at the rear, plus a slim three-spoke steering wheel. The list of optional equipment was quite long – those who wanted could easily push the price of the 318is, which was only available as a two-door, to over 40.000 DM.

To answer the question of why the 318is became the favorite of this article series, we need to zoom back two years before the four-valve engine's premiere in the E30's history. In 1987, BMW introduced the biggest facelift of the E30 series, which also brought a new generation of four-cylinder engines (internally M40) – from 1987 as the 318i, and from 1988 also as the 316i. The engine base had nothing in common with its predecessor, whose roots dated back to the 1960s. Everything was new.

As sometimes happens with complete new developments, not all beginnings were optimal, to put it mildly. The engine had two serious birth defects. With the timing belt, too few teeth were engaged simultaneously, making the load on each tooth too high. Initially, BMW prescribed a replacement after 80.000 km, which was then quickly reduced to 60.000 and finally to 40.000 km. In my two E30s, I replaced it every 35.000 to 40.000 km – and was never too early.

The second major issue was the insufficiently oiled camshaft. Many M40s eventually only revved up to 4500/min because the camshaft had worn so much that the valves no longer opened far enough. Driving an engine hard when cold is generally not particularly smart, but here it was even more disadvantageous. If low-quality oil is added, wear progresses rapidly.

In addition to careful warm-up and thin oil, replacing the oil supply rail above the camshaft with every timing belt change provides some relief. It's only three additional screws, as the valve cover has to be removed anyway. However, the rail (BMW part no. 11 42 1 727 054) now costs around 60 Euros at some dealers – 25 years ago it was just under ten. Frugal individuals at least thoroughly flush the rail once during the timing belt change, ensuring all bores are clear.

What to look out for?

To BMW's credit, they quickly learned from these weaknesses of the M40, and the first beneficiary was the 318is. It also has a 1.8-liter four-cylinder engine, but four valves per cylinder operated by two camshafts, and a solid duplex chain instead of a timing belt. This didn't solve all problems, but the most serious defects were eliminated. The cylinder head gasket needs attention, as it occasionally becomes leaky in the area of the timing chain cover. The timing chain itself is not problematic; from a mileage of 150,000 km, the chain tensioner should be checked and replaced if necessary. Apart from that, the engine is quite solid and, with careful handling, capable of very high mileage.

Of course, after at least 35 years, rust is also an issue with the E30, although BMW provided better protection than with its predecessor. Pay particular attention to the lower ends of the fenders, jack points including the sills, door edges, wheel arches, and the area around the rear towing eye. Be sure to lift the carpet in the trunk – leaky taillights can cause extensive hidden damage. The battery compartment is often heavily corroded, and the ellipsoid headlights, which were not very bright even when new, are often cloudy.

Inside, the driver's seat is often worn, the battery in the instrument cluster is dead, and the crank for the optional sunroof is loose. The differential and gearbox are rarely 100 percent leak-free and dry on the outside, but can be quickly sealed if necessary. None of these are major dramas, but they should naturally be considered in the cost calculation. The bushings on the rear axle are a bit different; their replacement, while not necessarily extremely expensive, is complex. BMW even had special tools for this at the time.

Market situation

Anyone who delves deeper into the E30 today will quickly realize that the 318is is not only one of the best engines in this model series, but unfortunately also no longer a secret tip. Compounding this is the fact that the 318is, introduced at the IAA in 1989, remained in the program for just over a year, as the E30 two-door could no longer be ordered new from early 1991. So, if you absolutely want this specific engine, you are limited to a rather small selection. As with the E21, I recommend not to limit the choice of engine too strictly in the first place.

Decent E30s can still be found on the market, but bargains are now the absolute exception. Sellers generally know what they are selling, and the number of well-maintained garage finds is, of course, decreasing significantly over the years. Even for the relatively less sought-after M40 four-cylinders that came after the '87 facelift, more than 8000 Euros are now required in good condition. A decent 318is without upcoming major repairs should easily cost more than 15.000 Euros. If it's even available on the market.

(mfz)