M43 1.6, 1.8 and 1.9 engine: faults and reliability

• M43B16, 1.6 litre (102 hp; 1993-1999)

  1993–1999 · 102 hp · M43B16

  With caution

  The sources describe the M43 as a very durable four-cylinder whose faults are with ancillaries after 20 years, mainly the plastic cooling parts and oil leaks. Buy with the cooling circuit renewed.^[1][2][3]

• M43B18, 1.8 litre (115 hp; 1993-1999)

  1993–1999 · 115 hp · M43B18

  With caution

  The E36 guide from Euro Premium Parts lists no faults specific to the M43B18 and presents it as more reliable than the M40, and Autohints describes it as one of BMW’s most durable four-cylinders; even so, at this age it is worth checking the cooling, gaskets and idle.^[1][6]

• M43TUB19, 1.9 litre (105 hp; 1998-2002)

  1998–2002 · 105 hp · M43TUB19, M43B19

  With caution

  Same base as the rest of the M43: durable mechanically, with plastic cooling parts and gaskets as the points to check; Enginescope and an owners’ forum also cite the leak from the front cover gasket on the M43TU.^[1][3][7]

• M43TUB19, 1.9 litre (118 hp; 1998-2002)

  1998–2002 · 118 hp · M43TUB19, M43B19

  With caution

  Like the rest of the M43, durable mechanically; check the cooling, the front cover gasket, the idle and the noise from the DISA valve.^[1][3][7]

Buy: No known serious faults, or they have already been corrected, in this version. With caution: Worth buying if something specific is verified: history, a replaced part or a completed campaign. Avoid: High risk of a serious fault that is hard to check for or prevent.

1. 1High severityFrequency: CommonCoolingFailure of the plastic parts in the cooling systemOn the M43 the expansion tank, water pump, thermostat, radiator and plastic flanges become brittle with age and crack. The priority is to avoid the engine overheating: Autohints advises switching the engine off if the gauge rises above halfway.
2. 2Medium severityFrequency: OccasionalIntakeDISA intake manifold valve with play and noiseThe DISA intake manifold flap on the M43 can develop play and rattle. Autohints warns that if it is left alone, broken pieces can end up in the intake; Enginescope says it is fixed with a repair kit or a new valve.
3. 3Low severityFrequency: CommonLubricationOil leaks from gaskets (rocker cover, front cover and crankcase breather)Over the years the M43’s gaskets harden and seep oil: the rocker cover gasket, the filter housing, the front cover (especially on the M43TU) and the crankcase breather valve. It is a common fault and, according to the sources, a minor one.
4. 4Low severityFrequency: OccasionalIntakeRough idle from the idle valve, intake boot or air mass meterThe M43’s idle becomes rough, or the engine stalls, when the idle control valve clogs with carbon, the rubber boot between the air mass meter and the manifold cracks (letting in false air), or the air mass meter fails. Cleaning the valve is usually enough.
5. 5Low severityFrequency: OccasionalIgnitionMisfires from worn coils, leads and spark plugsOn a high-mileage M43 the spark plugs, leads and ignition coil wear and cause rough running, judder and occasional misfires. These are wear items that are renewed as part of maintenance.

Severity colours: low, medium, high, critical. How we rate them

Manufacturer

BMW

Family

M43 (sucesor del M40)

Fuel

Petrol

Displacement

—

Cylinders

4

Fuel system

Naturally aspirated

Injection

Indirect injection

Timing

Chain

Power

102–118 hp

Peak torque

180 Nm

Production

1993–2002

Makes

BMW

Technical data^[2][4][5]

1. 1993–1999

   M43B16, 1.6 litre (102 hp; 1993-1999)

   Entry-level version: 1.6 litres, 75 kW (102 hp) and 150 N·m, with a single overhead camshaft, 8 valves and a timing chain instead of the M40’s belt. It powered the E36 316i from 1993 to 1999.^{[2][5][9][10]}

2. 1993–1999

   M43B18, 1.8 litre (115 hp; 1993-1999)

   1.8 litres, 85 kW (115 hp) and 168 N·m, the version fitted to the E36 318i and the Z3 1.8 (the latter from 1995 to 1998). It shares the 8-valve chain design and the DISA intake manifold with the 1.6.^[2][4][5][8]

3. 1998–2002

   M43TUB19, 1.9 litre (105 hp; 1998-2002)

   ‘TU’ revision of the M43 for the E46 (autumn 1998): 1.9 litres, 77 kW (105 hp) and 165 N·m. It reuses the M44’s short block and, according to English Wikipedia, this 77 kW version has no DISA manifold and uses a smaller camshaft than the 87 kW one. It powered the E46 316i and the E36 316i Compact (1999-2000).^[4][5][9]

4. 1998–2002

   M43TUB19, 1.9 litre (118 hp; 1998-2002)

   The 87 kW (118 hp) and 180 N·m version of the M43TU, with DISA manifold. It powered the E46 318i and 318Ci (1998-2001) and the Z3 1.9i until 2002.^{[4][5][8][11]}

• Timing chain kit

  • Buy part at Autodoc (affiliate link, opens in a new tab)

• Oil filter

  • Buy part at Autodoc (affiliate link, opens in a new tab)

• Air filter

  • Buy part at Autodoc (affiliate link, opens in a new tab)

• Spark plugs

  • Buy part at Autodoc (affiliate link, opens in a new tab)