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Jun 03, 2023

BMW Z4 (E86) 3.0Si Coupe

BMW Z4 Home » BMW Z4 (E86) 3.0Si Coupe – Buyer’s Guide Andrew Everett August 22, 2023 / 4 minutes read When the BMW E86 Z4 Coupe arrived in 2006, everyone, including me, assumed that BMW had a smash

BMW Z4

Home » BMW Z4 (E86) 3.0Si Coupe – Buyer’s Guide

Andrew Everett

August 22, 2023 / 4 minutes read

When the BMW E86 Z4 Coupe arrived in 2006, everyone, including me, assumed that BMW had a smash hit on their hands. It combined the many virtues of the E85 Z4, plus 258 bhp from a new engine and stunning styling. Well, it didn’t work out like that. Maybe a 170 bhp 2.0i version would have helped? Who knows. However, the BMW Z4 Coupe has become a modern classic and an alluring package. It has a proper parking brake and a raw, gutsy feel compared to the E89, adding to an already convincing set of virtues.

The 258 bhp N52 engine is a real gem. While the original Z4 Roadster used the 231 bhp M54 from the late Z3 and the E46/E60, the all-new N52 launched in ‘05 was superb and thankfully unencumbered by the later direct injection setup used on the 2008 N53 and its injector and carbon buildup problems. The N52 3.0 liter is probably the zenith of BMW straight sixes but does have some potential issues. The really expensive problem is where the steel oil sealing rings at the front of the cams can wear a groove into the alloy cam carrier. They are there to maintain oil pressure activating the Vanos units, and when worn, the engine light comes on because the Vanos isn’t operating correctly due to insufficient oil pressure.

But it’s not that common, and we’ve seen 150,000-mile N52s that are fine. The killer is that the inlet bearing ledge is integral with the head. If the inlet bearing ledge is worn, you need either a new head assembly at a mere £4000 or a used engine that may be on the verge of a similar problem. The exhaust bearing ledge is replaceable and costs £365 plus 4-5 hours of labor. A light chattering noise from the engine often sounds like a piston issue but is actually wear in the cam carriers allowing the lifters to ‘rock’ slightly.

Oil changes are critical, so change the oil every year or 8000 miles with a fully synthetic. The N52 has an electric coolant pump, and they are at an age where they may fail. From BMW, a new pump is just over $500, but you can buy the same Pierburg pump elsewhere for less. The Valvetronic system rarely fails, and the same goes for the Vanos gears, although the actuators can. Only use genuine parts.

The Getrag GS6 six-speed manual is a tough gearbox and rarely gives trouble, while the dual-mass flywheel has an easy life. Some cars have the six-speed ZF automatic. While you can leave it alone, some say an oil and filter change at 50,000 to 100,000 miles is a good idea. Oil leaks from the pan oil seal or the electronic connector plug need fixing. I would only use genuine parts from ZF or BMW.

The cheaper oil pans can warp and leak, rendering the whole thing a waste of time. The autos rarely fail, and shifting problems are normally due to a faulty solenoid or the rubber “bridge” seal between the mechatronics valve block and the transmission casing. Driveshafts and final drives are all very similar to the E46 330i and are just about unbreakable.

The Z4 inherited the E46-style Z axle. The E46 boot floor cracking around the rear subframe mounts is unheard of. The front end is basically E46 as well. Common issues both front and rear will be worn rear trailing arm outer bushes, as well as the front wishbone rear bushes, but use genuine BMW parts and do the job once.

The electric PAS system? Hmmm. The Z4 range – apart from the BMW Z4M – had an electric motor on the column. It works well, but hope that it doesn’t fail because a new one is a staggering £2600 – that’s before fitting and coding. Used columns require caution because they need to be removed in the locked position from the donor car. Is there a market for a fluid PAS conversion using an E46 rack?

Use a PAS pump from an E46 or E60, pipework, and a modified column. You’ll need a remap to restore lost throttle response from the Sport button – it is activated by the electric steering motor. But all Sport mode does is vary the speed at which the throttle reaches full throttle status so it’s not that important… or is it?

Standard rims on the Coupe were all 18-inch alloys but of different styles. The most common is perhaps the Style 135 MV2 alloy wheel, similar to that used on the later E46. But an optional split-rim style 108, the “Composite Star spoke” wheel was quite often specced when new. You’re looking at about £200 for a pair of tires – Hankook Optimo K415’s are £180 a pair plus fitting, while Continental Sport Contacts are closer to £250.

The ABS pump/ECU unit is expensive new at almost £2000, but they rarely fail. Corroded brake pipes are common now on cars not from hot states, but a nicely garaged car should still be on good, clean original pipes. Parking brake lever ratchets can occasionally strip the teeth, but a new lever is cheap enough at around £130 and is easy enough to fit.

The BMW Z4 range doesn’t seem to rust, even though the oldest ones are now 20 years old. Remember when a Miata, MGB, or TR7 was little more than bran flakes at that age? The only rust area on the coupe is the inner tailgate seams, only visible with the rear hatch open. Look around the whole car for signs of badly repaired damage, such as irregular shut lines. The car should still be straight and clean even at 15 or more years old, so make sure everything looks and works properly. Central locking problems could be due to a GM module, a dying key battery, or a faulty lock, but none are a king’s ransom to fix.

The Z4 Coupe inherited most of the Z4 Roadster’s interior, but depending on the build year, standard equipment was far from generous. PDC was a very useful option that’s worth having. The professional nav might have been a deal-breaker back in 2008, but your phone is better in 2023. Standard equipment numbered a single-slot CD player and not much else, but ask yourself what you need. Electric seats are common, so make sure they all work as they should.

You have a choice of standard halogen and xenon headlights. If you like to see where you’re going on a dark, wet night, the xenons are essential. If you need a new one, though, be prepared for the shock when the dealer tells you how much a new headlight costs – it’s a lot. The screen wiper linkage can break, and a good used linkage is the best option – they’re about $300 new.

The power windows use a cable and motor system, and they’re just under $200 per side, with no cheaper option unless you buy used. There is no troublesome electric hood motor, though, so it’s mostly good news.