Alfa Romeo 166 (Type 936: 1998-2007)

Used, black Alfa Romeo 166 on OEM alloy wheels. A post-facelift model.

The Alfa Romeo 166 was restyled in 2003 – a post-facelift model above.


Reliability & common problems

This section covers the potential reliability issues that you might have with the Alfa Romeo 166. Click on the buttons below to read more about the typical problems that fall outside the scope of routine maintenance.

Fragile suspension

Watch out for suspension noises (knocking and squeaking) when buying an Alfa Romeo 166. The suspension is relatively fragile in this car and other Alfa Romeos from that era. When it’s worn out or out of alignment, the car likes to eat the tyres quickly (tyre wear on the inner edge).

The suspension in the Alfa Romeo 166 will likely need refreshing every 50k miles or so. If you happen to drive on bad roads or use cheap suspension parts, take 50% off this number.

When buying an Alfa Romeo 166, take it for a test drive on some rough road and some speed bumps. Listen for any suspension noises. Also, check if the tyres are worn evenly.

V6 Busso – timing belt replacement interval

According to the manufacturer, the timing belt in this engine needs to be replaced every 72,000 miles or 5 years, whichever comes first.

In my opinion, this is too optimistic as there have been cases of the timing belt breaking earlier. I recommend getting it replaced not later than 60,000 miles.

Better safe than sorry.

2.0 Twin Spark – sensitive to poor maintenance

The Twin Spark is a dual ignition engine, which means that there are two spark plugs per cylinder (8 in total). The idea behind it is that igniting the air/fuel mixture in two places makes it burn quicker, thus improving efficiency and emissions. The dual ignition was dropped in later Alfa Romeo engines, probably because its benefits were too small.

Fun fact: dual ignition is still commonly used in aircraft engines for redundancy (the entire ignition system is duplicated, not just the spark plugs).

The Twin Spark engines are sensitive to poor maintenance.


Crankshaft bearings

First of all, a low oil level will kill the crankshaft bearings very quickly in these engines. For this reason, the oil needs to be changed regularly and oil level checked religiously to make sure it’s not low. Many old Twin Spark engines consume more engine oil than an average car. This usually isn’t a problem as long as the oil level is maintained.

The oil level in a Twin Spark engine should be checked monthly if not weekly (seriously).


Timing belt

Second, the timing belt in these engines isn’t very strong. It is very important to replace it every 36,000 miles or every three years, whichever comes first. This has to be done without fail as these belts are known to snap without warning. The belt replacement interval was only revised to 36k miles after many engines suffered timing belt failure (initially, the interval was 72k miles).

There are two timing belts in the 2.0 TS. One drives the valvetrain, while the second one turns two balance shafts. If any of the belts break, the results are catastrophic for the engine. Both belts need to be replaced at the same time.

Avoid engines that had the top end recently rebuilt after the timing belt had snapped. In this engine, a timing belt failure is sometimes followed by crankshaft bearings failure, which may get damaged when the valves hit the pistons when the timing belt breaks.

The bottom line is that these engines can be reliable as long as they are maintained well. Ideally, buy the car from an Alfa Romeo enthusiast.

2.0 Twin Spark – short-lived variators

All 16-valve Twin Spark engines (except the 105 PS 1.6L) are equipped with a device called the variator that adjusts the timing of the inlet camshaft (variable valve timing). The variator in the Twin Spark engines is not very durable and tends to wear out fairly quickly. A worn out variator makes the engine sound like a diesel.

Initially, the sound only appears after a cold start – before the oil gets pumped to the top of the engine. The clatter gradually gets more persistent. If your car sounds like a London taxi – get the variator replaced immediately.

The variator in the TS engines can fail as early as 40,000 miles. It makes sense to have it replaced with every timing belt job. The timing belt needs to be removed to replace the variator anyway.

2.4 JTD M-Jet 20v – timing belt & water pump

According to the manufacturer, the timing belt in this engine needs to be replaced every 72,000 miles or 5 years, whichever comes first. In my opinion, this is too optimistic. I recommend getting it replaced not later than 60,000 miles.

The water pump must be replaced at the same time as the timing belt, otherwise, it can seize and cause the timing belt to snap. It’s actually the water pump that is the weak point in the timing belt drive and the first part to fail.

The water pump in the 2.4 JTD MultiJet 20v is the same as in the 1.9 JTD MultiJet 16v, so both engines are affected.

2.4 JTD M-Jet 20v – swirl flaps

From mid-2005, these engines were fitted with swirl flaps in the intake manifold in order to improve emissions. There are two types of intake manifolds that were used on the JTD and MultiJet engines.

Luckily, the 2.4 JTD 20v has the safer aluminium manifold with plastic swirl flaps. These rarely fall off, unlike the metal ones that sometimes get detached and ingested by the engine.

In these engines, the swirl flap bearings wear out when the carbon build-up in the intake manifold becomes severe (it will eventually). Once the bearings are worn, they may develop air leaks, allowing the boost pressure to escape. Also, the flaps can simply get stuck before the bearings wear out.

Stuck or leaking swirl flaps manifest as rough engine running, reduced fuel economy and reduced power. The “Check engine” light may turn on as well.

The main cause of flap failure is increased friction in the flap mechanism from the carbon build-up in the intake manifold. Carbon build-up is a byproduct of the exhaust gas recirculation system (EGR) that feeds exhaust fumes back into the engine to improve emissions.

To fix the swirl flaps, a new intake manifold is required, which is fairly expensive. Another option is to remove the swirl flaps altogether, which has a minimal impact on the engine running. There are swirl flap removal kits available on the market.

Please be aware that removing the swirl flaps will increase emissions and is probably illegal – it depends on the country you live in.

2.4 JTD M-Jet 20v – worn drive shafts

The 20-valve JTD engine has an appetite for drive shafts. It seems that the General Motors drive shafts used in the 20-valve JTD cars are weaker than the Alfa Romeo ones used in the 10-valve JTD cars.

Make sure the drive shafts are in good condition in the car you are planning to buy, so you don’t get shafted. Look out for vibration when accelerating. It may be more noticeable in high gears at speeds above 50 mph.

Also, take the car to a parking lot or some other place where there is enough room to manoeuvre. Open both front windows, turn the steering wheel all the way to one direction, then do a circle. Listen for any noises coming from the CV joints.

Here’s what you don’t want to hear:

Summary or problems & additional information

  • As this is an Alfa Romeo, I must address the main question. Is the Alfa Romeo 166 reliable? Actually, it can be reliable apart from the fragile suspension and also fragile Twin Spark engine. Keep in mind that Alfa Romeo cars are performance oriented and not as robust and forgiving as Japanese cars when it comes to poor maintenance.

  • All engines in the Alfa Romeo 166 have timing belts. I think that the original timing belt replacement intervals are too optimistic for most of the engines in the Alfa Romeo 166. Follow this link to learn more about cambelts and why it’s important to replace them on time.

  • If you’d like to buy a car with the 2.0 TS, find one with a documented service history. The Twin Spark engine is a delicate flower – it needs correct maintenance to last. I think that the V6 is a better choice.

  • The V6 “Busso” doesn’t have any major flaws. Great sound too. Just watch the oil consumption. The factory spec oil is fairly thick because this engine has its origins in the 1970s, so it’s not a “modern” design. The 3.2L may use more oil than it’s smaller siblings due to smaller oil control rings.

  • The Alfa Romeo 166 is one of the last Alfa Romeo cars that you can buy with the famous “Busso” engine. The production of this V6 unit ended in 2005. The designer of this engine, Giuseppe Busso, died three days after the production stopped.

  • The 10-valve 2.4 JTD is a reliable common rail engine. After all, the world’s first common rail passenger car was an Alfa Romeo 156 powered by the 1.9 JTD. The 20-valve JTD M-Jet is also good but with a few more potential problems. Avoid the last years of production because of the stupid swirl flaps (from mid-2005). Also, watch out for worn out drive shafts in the case of 20-valve engines.

  • The things that could go wrong with the JTD engines are typical for common rail diesel engines. Follow this link to an article that might help you decide if a common rail diesel is the right choice for you.

  • Some of the last 2.4 JTD M-Jet 20v (180 or 185 PS) engines may have diesel particulate filters (in some markets).

  • Fun fact: the Alfa Romeo 166 was chosen as Britain’s fastest depreciating second-hand car. Apparently, the Alfa Romeo 166 held only about 15% of its original value after three years.

  • The Alfa Romeo 166 changed its looks quite significantly after the facelift in 2003. Below is what the original version looks like.

Used, grey Alfa Romeo 166 on OEM alloy wheels. Pre-facelift model
Alfa Romeo 166 before the 2003 facelift


Alfa Romeo 166 specifications

This section contains Alfa Romeo 166 specifications. You will also find technical information regarding the engines used in these cars. Press the buttons below to display the specs and engine technical details.

Petrol engines – specs & performance figures

2.0 Twin Spark1970 cm³ / 120.2 cu in155 PS / 114 kW187 Nm / 138 lbf⋅ftUntil 2000
2.0 Twin Spark1970 cm³ / 120.2 cu in150 PS / 110 kW181 Nm / 133 lbf⋅ft2000-2006
2.0 V6 Turbo1996 cm³ / 121.9 cu in205 PS / 151 kW280 Nm / 206 lbf⋅ftItalian market
2.5 V6 24v2492 cm³ / 152.1 cu in190 PS / 140 kW222 Nm / 164 lbf⋅ftUntil 2000
2.5 V6 24v2492 cm³ / 152.1 cu in188 PS / 138 kW221 Nm / 163 lbf⋅ft2000-2006
3.0 V6 24v2959 cm³ / 180.6 cu in226 PS / 166 kW275 Nm / 203 lbf⋅ftUntil 2000
3.0 V6 24v2959 cm³ / 180.6 cu in220 PS / 162 kW265 Nm / 195 lbf⋅ft2000-2006
3.2 V6 24v3179 cm³ / 194 cu in240 PS / 176.5 kW289 Nm / 213 lbf⋅ftFrom 2003

Diesel engines – specs & performance figures

2.4 JTD2387 cm³ / 145.7 cu in136 PS / 100 kW304 Nm / 224 lbf⋅ftUntil 2000, 10-valve "UniJet" engine
2.4 JTD2387 cm³ / 145.7 cu in140 PS / 103 kW304 Nm / 224 lbf⋅ft2000-2002, 10-valve "UniJet" engine
2.4 JTD2387 cm³ / 145.7 cu in150 PS / 110 kW305 Nm / 225 lbf⋅ft2002-2005, 10-valve "UniJet" engine
2.4 JTD M-Jet 20v2387 cm³ / 145.7 cu in175 PS / 129 kW385 Nm / 284 lb-ft2003-2006, 20-valve "MultiJet" engine
2.4 JTD M-Jet 20v2387 cm³ / 145.7 cu in185 PS / 136 kW or 180 PS /132 kW385 Nm / 284 lb-ft2006-2007, 20-valve "MultiJet" engine

Petrol engines – technical details

EngineEngine config.Forced inductionValve timingFuel deliveryDMFInlet flaps
Legend:SOHC - Single Overhead Camshaft
DOHC - Double Overhead Camshaft
VVT - Variable Valve Timing
EFI - Electronic Fuel Injection
DMF - Dual-mass Flywheel (does not apply to auto. transmissions with torque converters)
VLIM - Variable Length Intake Manifold
2.0 Twin SparkInline-4, 16 valvesNoTiming belt, DOHC, VVTPort injection (EFI)YesVLIM
2.0 V6 Turbo "Busso"V6, 12 valvesTurboTiming belt, SOHCPort injection (EFI)YesNo
V6 24v "Busso"V6, 24 valvesNoTiming belt, DOHCPort injection (EFI)YesNo

Diesel engines – technical details

EngineEngine config.Forced inductionValve timingInjection systemDMFDPFSwirl flaps
Legend:SOHC - Single Overhead Camshaft
DOHC - Double Overhead Camshaft
DPF - Diesel Particulate Filter
DMF - Dual-mass Flywheel (does not apply to auto. transmissions with torque converters)
2.4 JTDInline-5, 10 valvesTurboTiming belt, SOHCCommon Rail (1st gen, "UniJet")YesNoNo
2.4 JTD M-Jet 20vInline-5, 20 valvesTurboTiming belt, DOHCCommon Rail (2nd gen, "MultiJet")YesSome 180 & 185 PS enginesYes (from mid-2005)


Alfa Romeo 166 wheel sizes

Press the button below to see the original equipment manufactuer (OEM) rim & tyres sizes for the Alfa Romeo 166. These are the original wheel sizes that were fitted by the manufacturer.

TyresRims Centre BoreBolt PatternComments
205/55 R16 6.5Jx16 ET41 or ET36.558.1 mm5x108ET41 does not fit over Brembo brakes
215/55 R16 7Jx16 ET4158.1 mm5x108V6 cars
225/45 R177.5Jx17 ET4158.1 mm5x108V6 cars
235/40 R188Jx18 ET36.558.1 mm5x108Alfa Romeo 166 Ti


Share this page:

Leave a Reply

Your email address will not be published. Required fields are marked *

eighteen + nine =