Models · BMW
BMW 3 Series E46 buying guide
The fourth-generation 3 Series, built from 1998 to 2006 as a saloon, coupé, convertible, Touring and Compact. Most cars have a straight-six petrol or a four-cylinder diesel, and the faults are well known and mostly straightforward to check.
The versions
- Four-cylinder petrols: 316i and 318i (M43 to 2001, then the N42 and N46 with Valvetronic)
- Six-cylinder petrols: 320i, 323i and 328i (M52TU) to 2000, then the M54 in the 320i (2.2, 170PS), 325i (192PS) and 330i (231PS)
- Diesels: 318d and 320d (M47 four-cylinder, 320d 150PS from 2001), 330d (M57 six-cylinder, 184PS then 204PS)
- Saloon, coupé, convertible, Touring estate and Compact hatchback; four-wheel drive on the 325xi, 330xi and 330xd saloon and Touring
- 5- or 6-speed manual, or automatic
What to check on a E46 3 Series
3 model-specific things to look at when you view one. They're a starting point, not the full inspection.
The cooling system's plastic parts
What to look for: With the engine cold, look at the coolant expansion tank for hairline cracks and staining around its seams, and at the radiator's plastic end tanks and the hoses for crusty residue. Check the level is between the marks, and ask what cooling parts have been replaced.
Why it matters: On the six-cylinder cars the expansion tank, radiator end tanks, thermostat housing and the water pump's impeller are plastic and crack or fail with age. Overheating from a failed part is a leading cause of serious engine damage on these engines, so an invoice for a cooling refresh is one of the best things to find in the file.
Cracks at the rear subframe mountings
What to look for: From underneath with a torch, look at the floor of the car where the rear subframe bolts to the body, just ahead of the rear wheels. Look for cracks in the metal around the mountings, or reinforcement plates welded in. On the drive, listen for clicks or clonks from the back when accelerating and braking.
Why it matters: Cracking of the body around the rear subframe mountings is a well-documented E46 issue, especially on the earlier saloons and coupés. Caught early it's repaired with reinforcement plates. Plates already fitted by a specialist are a good sign rather than a bad one.
Crankcase breather and vacuum leaks
What to look for: With the engine idling, listen for a whistle or hiss from the engine bay and note whether the idle is steady. Ask how much oil it uses between services, and look for oil around the dipstick tube and oil filler.
Why it matters: On the M54, a failed crankcase ventilation valve, a cracked lower intake pipe or perished vacuum hoses cause vacuum leaks, oily blow-by and rising oil consumption. Most cars need the breather system renewing at some point, and it's a known, contained job.
Also in the full guide
- Rattle at idle and VANOS
- Oil leaks from the gaskets
- Window regulators
- Four-cylinder petrols: oil use and Valvetronic
- The cold start, test drive and paperwork checks for the exact version you're viewing
The full guide to the E46 3 Series
The CrankSight guide walks you round the car on your phone at the viewing, with every check for the exact version you're looking at: what to look for, where to find it, and what anything you find is likely to cost. As you go it builds an assessment of that car, and if you view more than one, it lines them up side by side.
£29 for the model, used on as many cars as you like, delivered within 72 hours or your money back.
Other generations
BMW 3 Series E36 · BMW 3 Series E90/E91/E92/E93 · BMW 3 Series F30/F31/F34 · BMW 3 Series G20/G21
General points for the model, last checked October 2026. Every car is different, so treat this as a guide to what to look at, not a verdict on any car. CrankSight is independent and has no connection with BMW.