BMW E24 6-Series, The Complete Buying Guide

Overview

The BMW E24 6-Series (1976-1989) is one of the most beautiful grand tourers ever built. Paul Bracq’s shark-nose design, the pillarless coupe body, and the mechanical simplicity of the M30 straight-six make it a genuine icon. These are cars that were designed for sustained high-speed cruising on the autobahn, and they do it with an effortless elegance that modern BMWs cannot replicate.

For the Australian buyer in 2026, the E24 market has matured significantly. The days of finding a running 635CSi for $8,000 are gone. Clean, roadworthy examples now start at $40,000 AUD, well-sorted cars fetch $50,000-60,000, and the M635CSi (or US-market M6) commands $150,000 and upwards. Project cars still surface for $10,000-20,000, but the cost of a proper restoration will exceed the value of the finished car unless you do the work yourself.

The E24 was produced for thirteen years, and there’s a significant difference between early carburetted 630CS models and the final fuel-injected 635CSi with Motronic engine management. For Australian buyers, the 633CSi and 635CSi were the officially imported variants, with the 635CSi being by far the more common survivor.

This guide is written for the person who wants to buy an E24, drive it, and keep it running. Not a concours trailer queen, a real car.

Which Variant to Buy

630CS (1976-1979)

The base model with the M30B28 2.8-litre six and Solex 4A1 carburettor. Not officially sold in Australia. These occasionally surface as grey imports and should be approached with caution, the carburettor setup requires specialist knowledge and parts sourcing is difficult. The 630CS makes 136 kW, which is adequate but not exciting in a 1,500 kg coupe. Unless you specifically want a carburetted car for the aesthetic, skip it.

633CSi (1976-1984)

The 633CSi was the first E24 officially imported to Australia. It uses the M30B32 3.2-litre six with Bosch L-Jetronic fuel injection, producing 143 kW. This is a solid, well-mannered engine that’s smooth and torquey. The L-Jetronic system works well when all the sensors and wiring are in good condition, but troubleshooting it requires an understanding of the analogue fuel injection system, there’s no OBD port, no fault codes, just voltage readings and fuel pressure measurements. A well-sorted 633CSi is a lovely car, but the 635CSi is better in every measurable way.

635CSi (1978-1989)

This is the one to buy. The 635CSi uses the M30B34 3.4-litre six with Bosch Motronic digital engine management (from 1982 onwards). Power is 160 kW in Motronic form, and the engine is remarkably refined. The Motronic system is far more reliable and easier to troubleshoot than the earlier L-Jetronic, and it delivers better fuel economy and smoother running. The 635CSi was the most popular E24 in Australia and consequently the easiest to find parts for. Late-model 635CSi cars (1985-1989) benefit from numerous small improvements: better interior materials, improved air conditioning, uprated brakes, and the refined M30B34 engine with Motronic 1.3.

This is the sweet spot. A late 635CSi with Motronic gives you 90% of the E24 experience at 30% of the M635CSi price.

M635CSi (1984-1989)

The M635CSi uses the M88/3 engine, a 3.5-litre DOHC twenty-four-valve straight-six derived from the BMW M1 supercar. It produces 210 kW and 340 Nm, and the sound it makes at 6,500 rpm is one of the great automotive experiences. The M635CSi also received uprated suspension, larger brakes, a limited-slip differential, and an M-Technic body kit.

The M635CSi is a collector car now. Finding one in good condition under $150,000 is increasingly difficult. Running costs are substantially higher than the 635CSi, the M88 engine has a timing chain driven by a single-row chain that stretches, the valve adjustment requires specialist shims, and parts like the individual throttle bodies (ITBs) are expensive to rebuild. If you can afford to buy one and maintain it properly, it’s magnificent. If the purchase price stretches your budget to the point where maintenance becomes a concern, buy a 635CSi instead.

Critical Inspection Points

Rust, The Number One Killer

The E24’s rust traps are well-documented, and any car that hasn’t been meticulously maintained will have structural corrosion. This is not cosmetic, structural rust on an E24 requires cut-and-weld panel fabrication that will cost thousands.

• Front subframe mounts: Get underneath and inspect where the front subframe bolts to the body. Corrosion here is structural and expensive to repair. Poke with a screwdriver, the metal should be solid. If it’s soft or flaky, walk away unless you’re buying a project.
• Rear trailing arm pickup points: The rear suspension trailing arms bolt to mounting points that are prone to corrosion from road spray. Weakened mounts cause the rear suspension geometry to shift, which manifests as vague handling and uneven tyre wear. Repair requires welding reinforcement plates.
• Windscreen surround: The rubber windscreen seal traps moisture against the pinch weld. By the time you see bubbling paint around the windscreen, the metal underneath is often severely corroded. Pull back the rubber seal at the bottom corners and inspect. Windscreen surround repairs require removing the glass and are labour-intensive ($2,000-4,000).
• Door bottoms: The pillarless coupe doors are complex pressings with drain holes that block. When the drains block, water sits inside the door skin and rots from the inside out. Check the bottom edge of each door, bubbling paint or filler means the door skins are corroded.
• Boot floor and spare wheel well: Lift the carpet in the boot and check for rust in the floor pan and around the spare wheel recess. Water enters through failed boot seal rubber and around the tail light housings.
• Sills and jacking points: The outer sills are double-skinned and trap moisture. Jacking point corrosion is common and means the car cannot be safely lifted. Check by pressing firmly on the sill covers, they should be solid, not crunchy.
• Inner front wings: Where the inner wing meets the strut tower and firewall. Mud and road grime accumulate here and hold moisture against the metal.

Engine

M30 (633CSi, 635CSi): The M30 is one of BMW’s most durable engines. With regular oil changes and a functioning cooling system, these engines routinely exceed 300,000 km. However, neglected examples develop issues.

• Check for oil leaks around the valve cover gasket, oil pan gasket, and rear main seal. Some seepage is normal on a 40-year-old engine; heavy leaks indicate neglect.
• Listen for timing chain rattle on cold start. The M30 uses a single-row timing chain with a hydraulic tensioner. When the tensioner wears, the chain rattles on startup until oil pressure builds. A worn timing chain that jumps teeth will damage the head. Chain and tensioner replacement: $800-1,500.
• Check the head gasket, look for coolant in the oil (milky residue under oil filler cap) and oil in the coolant (oily film in the expansion tank). M30 head gaskets are generally reliable, but overheating events kill them.
• On L-Jetronic cars (early 633CSi), check for rough idle and flat spots in acceleration. The air flow meter (Bosch 0280202048) is the most common failure point and costs $400-800 to replace or rebuild.
• On Motronic cars, check for smooth idle and clean throttle response. Motronic faults are usually related to the coolant temperature sensor, oxygen sensor, or idle control valve, all relatively cheap to replace.

M88 (M635CSi):

• Listen for mechanical noise from the top end. The M88 has bucket-and-shim valve adjustment that needs checking every 20,000 km. Ticking from the top end is normal when cold; persistent ticking when warm means the valve clearances need adjustment ($400-600 at a specialist).
• Check timing chain tension. The M88’s single-row chain stretches more readily than the M30’s. A rattling chain needs immediate attention.
• Inspect the individual throttle bodies for vacuum leaks. Cracked rubber intake boots between the ITBs and the head cause rough idle and poor fuelling.

Gearbox and Drivetrain

• Manual gearbox (Getrag 265): The five-speed manual is strong and long-lived. Check for difficulty selecting second gear (synchro wear) and for oil leaks from the input shaft seal. A gearbox rebuild runs $2,000-3,500.
• Automatic (ZF 4HP22): The automatic is adequate but robs the engine of its character. Check for smooth shifts, no slipping, and clean red ATF. A rebuild costs $2,500-4,000.
• Differential: The E24 uses a limited-slip differential (standard on M635CSi, optional on 635CSi). Check for whining or clunking from the rear. Diff rebuilds cost $1,500-2,500. The diff mount bushings perish and cause clunking over bumps, replacement bushings are $60-100 and the job takes two hours.
• Driveshaft: Check the centre support bearing and the guibo (flex disc). The guibo is a rubber coupling between the gearbox output and the driveshaft, it cracks and tears with age. Replacement: $80-150 for the guibo, $150-250 for the centre bearing.

Suspension and Steering

• Front struts: MacPherson strut design. Check the strut top mounts for cracking and the strut tower for stress cracks. Replacement struts: $400-600 per pair (Bilstein B6 recommended).
• Rear semi-trailing arms: Check the bushings for cracking and the trailing arm pivot points for play. Worn bushings cause vague rear-end handling. Bushing replacement: $300-500 per side at a workshop.
• Steering box: The E24 uses a recirculating ball steering box that develops play with wear. Check for excessive free play at the steering wheel (more than about 10mm at the rim). A rebuilt steering box costs $800-1,200. Do not adjust the steering box to take up play, this causes binding and is dangerous.
• Power steering: Check the power steering pump for leaks and whining. The high-pressure hoses deteriorate and leak. Budget $300-500 for hose replacement.

Interior

The E24 interior is beautifully appointed and difficult to restore. Parts are scarce and expensive.

• Dashboard cracks: The E24 dashboard is infamous for cracking from UV exposure. Nearly every car in Australia has dashboard cracks. A replacement dashboard is $1,500-3,000 if you can find one. Dashboard recovering is $800-1,500. Dashboard caps are a cheaper option at $300-500 but they look like dashboard caps.
• Window regulators: The pillarless doors use complex regulators that fail regularly. Both front and rear windows can fail. Replacement regulators: $200-400 each. Fitting is a half-day job involving door panel removal and careful adjustment.
• Seats: The driver’s seat bolster wears through on every E24. Retrimming the driver’s seat costs $500-800. Check the seat adjustment mechanisms, the tilt function often seizes.
• Air conditioning: If the A/C doesn’t work, budget $1,500-3,000 to get it operational. The compressor, evaporator, and condenser are all specific to the E24 and increasingly difficult to source. Many systems have been converted from R12 to R134a with mixed results.

Running Costs

The E24 is not cheap to run, but it’s not catastrophic if you plan ahead and find a good independent BMW specialist. Do not take an E24 to a general mechanic, find someone who knows E24s or learn to do the work yourself.

• Service intervals: Oil and filter every 10,000 km or annually. Valve adjustment (M88 only) every 20,000 km. Spark plugs every 30,000 km. Coolant flush every two years.
• Tyres: The E24 wears 205/55R16 (standard) or 225/50R16 (M635CSi). Budget $800-1,200 for a set of quality tyres.
• Insurance: Agreed-value insurance through a classic car insurer is essential. General insurers will undervalue the car. Expect $800-1,500 per year depending on the agreed value and your driving history.
• Fuel consumption: 12-15 L/100km in mixed driving for the 635CSi. The M635CSi drinks 14-18 L/100km. These are 98 RON cars.
• Registration: Varies by state. Classic car registration schemes (club plates) can reduce costs significantly, typically $100-300 per year versus $700+ for full registration.

What to Pay (2026 AUD)

Variant	Project	Driver	Excellent
633CSi	$12,000-18,000	$25,000-35,000	$40,000-50,000
635CSi	$15,000-22,000	$35,000-50,000	$55,000-70,000
M635CSi	$50,000-80,000	$100,000-140,000	$150,000-200,000+

A “driver” is a car that’s roadworthy, mechanically sound, and presentable but not perfect. An “excellent” car has a documented service history, no rust, a good interior, and needs nothing.

The Verdict

The E24 6-Series is a genuinely great car that rewards patient, knowledgeable ownership. The 635CSi is one of the best grand tourers of the 1980s, fast enough to be exciting, comfortable enough for long drives, and beautiful enough to stop people in car parks. Buy the best one you can afford, find a specialist who knows these cars, and budget for the first year of ownership to be expensive as you sort deferred maintenance. After that first year, an E24 is a reliable and deeply satisfying car to own.

Do not buy an E24 as a first classic car. Do not buy one without a pre-purchase inspection by someone who knows them. And do not buy one if you cannot afford to fix the problems that every E24 has. But if you understand what you’re getting into, the E24 is one of the most rewarding BMWs you can own.