Used BMW 635

What to know before buying: BMW 635

From 4 video reviews and 1 press test · updated 23/09/2026

What the reviews say

• The M635CSi's M88 is exceptionally smooth, responsive and great-sounding, combining a race-derived engine with comfortable GT manners.[1]one sourceBMW 6 Series E24
• The M635CSi has nicely weighted, communicative steering and a crisp five-speed manual; on the move it feels balanced, planted and confident.[4]one sourceBMW 6 Series E24
• The 635 CSi Highline feels firm yet secure through bends and well suited to fast long-distance touring, with notably little wind noise for its era.[3]one sourceBMW 6 Series E24
• The M635CSi's cabin is driver-focused, with comfortable, supportive seats and generous glass that gives an airy feel and strong visibility.[4]one sourceBMW 6 Series E24

Typical faults

• High-mileage M88 engines can leak oil from drain pipes, cam carriers and the front timing covers.[2]one sourceBMW 6 Series E24

  M88

• At roughly 161,000 km, the M88 timing chain needs major service. Replacement without removing the head and sump is described as incorrect and risks sealing problems.[2]one sourceBMW 6 Series E24

  161 000–161 000 km · M88

• On the M635CSi, ageing radiators and cooling hoses can become brittle and leak; water-pump failure can also cause overheating.[5]one sourceBMW 6 Series E24

  M88

• The E24 M635CSi is rust-prone around the arches, sills, floors, boot and windscreen; blocked sunroof drains can admit water and promote corrosion.[5][4]BMW 6 Series E24
• Worn suspension bushes can cause loose or vague steering and uneven tyre wear, while tired dampers degrade ride and handling.[5]one sourceBMW 6 Series E24
• As the Bosch injection system ages, injectors can clog or fail, causing poor running or starting difficulties.[5]one sourceBMW 6 Series E24

  M88

Which engine and version to take

• The M635CSi's 3.5-litre M88 is the enthusiast's choice: sources describe it as very strong, smooth and responsive when properly maintained and its timing gear is serviced.[2][1]BMW 6 Series E24

What to check at the inspection

• Closely inspect the arches, inner arches, sills, floors, boot, windscreen surround and sunroof drains; lift the carpets and look for damp or corrosion.[5][4]BMW 6 Series E24
• For an M88 car, demand proof of comprehensive timing service at about 161,000 km, covering the chains, guides, tensioners and crankshaft sprocket.[2]one sourceBMW 6 Series E24
• With the engine cold and warm, check for oil leaks around the cam carriers, front timing covers and oil drain pipes.[2]one sourceBMW 6 Series E24
• Inspect the radiator, hoses and water pump, monitor temperature on the test drive and look for evidence of previous overheating.[5][4]BMW 6 Series E24
• Test every electrical accessory and control, as age-related electrical trouble is specifically reported.[4]one sourceBMW 6 Series E24
• On the test drive, assess steering precision, noises, ride quality and tyre wear for signs of worn bushes or dampers.[5]one sourceBMW 6 Series E24

Verdict

Sources

1. [1]Number 27 — As Fast As A Ferrari, Cheaper Than M5 - Why You Need A BMW M635CSI · ▶ video
2. [2]Hero Motor Company — BMW M635 CSi Buying Guide Part 1 · ▶ video
3. [3]Classic & Sportscar Centre — BMW 635 CSi Highline Motorsport — дорожный тест · ▶ video
4. [4]High Peak Autos — I Drove the Original BMW M6 (Test Drive & Review M635CSi) · ▶ video
5. [5]elementperformance.co.uk — BMW E24 M635CSi Common Issues, Maintenance and ... · press

Spotted an error? Tell us