Buying Guide normally aspirated straight-sixes BMW 330i E90


So this is it – the last of the naturally aspirated straight-six BMW sports saloons. One obviously can’t definitively say that there won’t be another one at some point in the future, but for the time being it’s all about turbochargers, reducing emissions and the increasing use of electricity to power our cars. If this sounds like a situation you’re not quite ready for then step this way into the world of powerful, tuneful and soulful straight-sixes and bag yourself an E90 330i. The E90 is a great all-rounder and in 330i guise is a genuinely quick machine. Yet the flip side of the coin is that it’s eminently practical, comfortable and can be surprisingly economical when you’re not chasing down the redline.

When the fifth generation of 3 Series was revealed it shouldn’t have come as a shock that its design was wildly different from that of the rounded BMW E46 – after all the BMW E65/E66 Seven and the BMW E60 Five should have prepared us for BMW’s radical new design direction. The Three wasn’t as dramatic as its bigger brethren – perhaps BMW had toned down the Bangle influence for its biggest selling model – but it was still a handsome design, even if it was a little bland from the rear. The E90 had grown, being 49mm longer and 78mm wider than its predecessor, and BMW reckoned this offered rear seat passengers in particular more room while also increasing boot size by 20 litres. Thanks to the use of lightweight materials in the car’s construction it was also marginally lighter than the E46, despite the size increase.

The top dog in the model range was the 330i and this machine had been endowed with the new N52 straight-six that had been launched in the 630i in 2004. It used a mixture of aluminium and magnesium in its construction and featured Valvetronic variable valve timing, double Vanos, a dual length ‘Disa’ intake manifold, an electronic throttle and an electric water pump. Its vital stats were 258hp at 6600rpm and a maximum torque output of 221lb ft that was available between 2500 and 4000rpm which made it good enough for a 0-62mph time of 6.5 seconds and a top speed limited to 155mph. The flip side of the coin was an impressive average economy figure of 32.5mpg.

The E90 went on sale in March 2005 and initially the 330i was only available in SE trim and cost £28,455. It was pretty well-equipped straight out-of-the- box with a six-speed manual ‘box, automatic air conditioning, 17-inch alloy wheels, multi-function steering wheel, rear PDC, Professional radio/CD, six airbags, DSC+, metallic paint and an on-board computer. The M Sport model arrived in the latter part of 2005 and attracted a £2730 price premium over the SE model. It followed the by now familiar formula of an M aerodynamic kit, 18-inch Style 193 alloys, Sports seats, a cloth and Alcantara upholstery, sport suspension and high gloss shadowline trim.

Over the ensuing years there were some minor changes to pricing, options and spec, but the 330i’s major update came when the range went through its mid-life face-lift in 2008. The overall design of the E90 was subtly enhanced to bring it up-to-date and it featured a reshaped front bumper and lower valance while the headlights were also updated along with a new bonnet that featured what BMW called ‘precision lines’ to give the car a more dramatic look. At the side there were reprofiled sills and reshaped door mirrors while at the rear new tail-light clusters featured LED light technology and the rear bumper and bootlid were also reshaped. Inside, the biggest news was the introduction of a new iDrive system for customers who had spec’d one of the two navigation systems that were offered. A new iDrive controller combined with a new operating system and new menu features to deliver improved functionality and ease-of-use.

The 330i had also had a refresh under the bonnet too with the adoption of the new direct-injection N53 straight-six. Power was up to 272hp and torque had swelled to 236lb ft which was enough of an upgrade to improve the 0-62mph time to 6.1 seconds, yet the biggest claimed improvement was to economy, rising by an appreciable 18 per cent to 38.2mpg.

While there was nothing wrong with the face-lifted 330i it wasn’t a huge seller in either Saloon or Touring guises and BMW UK quietly dropped it from its lineup in early 2010, leaving buyers with the choice of either the 325i or the turbocharged 335i. And the normally aspirated petrol-engined BMW sport saloon died a quiet death. Gone, but not forgotten.


The N52 engine as used in the pre-LCI 330i is a great engine if not as robust as the old M54 used in the E46 model. Given regular oil changes (forget the Condition Based Servicing) it will whizz up to 200,000 miles and not much goes wrong with it. However, nothing’s perfect and there are a few things that can go wrong and cost a lot of money to sort out. The worst is wear to the camshaft bearing ledges. On this engine there are inlet and exhaust Vanos units and they require oil pressure to operate. This comes from an oil supply hole in the front cam bearing and to prevent oil escaping back past the bearing, there is a steel oil sealing ring on the cam bearing itself. All well and good but over time, this starts to wear a groove in the alloy cam carrier. Oil gets past the sealing ring, oil pressure drops, the Vanos unit can’t advance fully and it brings on the EML (Engine Warning Light).

If the fault lies on the exhaust cam you’re sort of in luck because the carrier is a replaceable part and the repair can be done for around a grand. But on the inlet cam, the carrier is integral with the head and so the repair costs are immense – enough to effectively write off an early car. Therefore make sure the car runs perfectly, the EML light comes on with the ignition and goes out again and change the oil every 8000 miles with a fully synthetic.

The LCI cars from 2008 started to use the N53 engine with direct injection using a high pressure fuel pump. The basic engine is similar to the N52 but now had removable cam carriers on both cams. On both units, Vanos problems are rare and often, the Vanos solenoids can be replaced to cure faults – they’re plentiful used and new ones are under £150 each. Despite the timing chain arrangement being similar to the four-cylinder petrols, the timing chain and guide rail setup seems better than the likes of the 318i and 320i where the chain is near enough an 80,000 mile service consumable.

The N53 direct injection system is okay, but any faults will be expensive to fix – a new pump is nearly £750, injectors are £245 each and the dreaded NoX sensor in the exhaust front pipe is £405. Annoyingly, the parts are still BMW only – a friendly Bosch agent might be able to get a new pump for less and a good used one should be around £200, but it still requires coding in. NGK make the NoX sensors but unless you know different, they will not (yet) supply the aftermarket. Catalysts are built into the exhaust manifolds but don’t seem to be a problem, but the electric coolant pumps are at the age when they may go wrong… but are surprisingly reliable.

A new one is £500 and don’t bother with used ones because once used, they need to be kept full of coolant if the seals aren’t to fail. If £500 is too much, ECP do an identical Pierburg pump brand new for £339 which isn’t bad. If you should need a new radiator, they are a pretty reasonable £256 from BMW – avoid cheap aftermarket ones as too often they will leak from the hose connections – but of the aftermarket ones, we’d be looking at Nissens or Valeo. Like the N42 and N46, the N52 and 53 can leak oil – cam cover gaskets and the Vanos solenoid oil seals are favourites.

ECUs and sensors aren’t a problem, but be aware that the ECU box can flood – if you have an E90 or derivative of any sort you must remove the lid, clear the drain holes and even drill a couple of decent sized extra holes to let water out. BMW N52 engine guide

BMW E90 330i Saloon
330i (2005-2008) / 330i (2008-2010)
ENGINE: N52 straight-six, 24-valve, petrol / N53 straight-six, 24-valve, petrol
CAPACITY: 2996cc / 2996cc
MAX POWER: 258hp @ 6600rpm / 272hp @ 6700rpm
MAX TORQUE: 221lb ft @ 2500-4000rpm / 236lb ft @ 2750-3000rpm
0-62MPH: 6.3 seconds (6.6) / 6.1 seconds (6.3)
STANDING KILOMETRE: 26.2 seconds (26.2) / 25.5 seconds (25.7)
50-75MPH (4TH GEAR):   6.5 seconds / 6.2 seconds
TOP SPEED: 155mph (155) / 155mph (155)
ECONOMY: 32.5mpg (31.4) / 38.2mpg (37.7)
EMISSIONS: 210g/km (216) / 173g/km (173)
WEIGHT (EU): 1525kg (1540) / 1555kg (1570)
PRICE: £28,455 (SE, 2005) / £34,185 (M Sport, 2010)
Figures in brackets refer to six-speed automatic gearbox

Buying one

Despite being a mass produced-machine sourcing an E90 330i isn’t straight forward – 330is sold in tiny numbers in the UK, especially when compared to the 320d, or the 330d. This means that if you have your heart set on a particular colour or spec and you have some must-have options on your wish list you may have a little bit of a wait in store.

Perhaps the biggest decision you’ll have to make will be whether to opt for a manual or an automatic – both are great ‘boxes, but we reckon the manual just brings out a bit more of the sporting character of the 330i. The bad news is that more 330is were sold with autos than manuals. Whether you opt for a pre- or post-face-lift machine will depend on your budget and whether you prefer the earlier or later styling, but it might also be worth thinking about the pros and cons of the N52 and N53 engines with the pre-LCI unit tending to be slightly more reliable, or less likely of throwing up an expensive bill. Get yourself familiar with the options list for the car and work out what are and aren’t priorities for you, and be prepared to make some compromises along the way. Sat nav is certainly nice to have, but the system in pre-LCI cars is getting quite long in the tooth – the face-lift system is significantly better.

Nearly all cars were ordered with leather trim – a £1200 option – but Sports seats were only standard on the M Sport model and electric adjustment was also a cost option. Bluetooth and DAB weren’t standard either so it’s worth checking to see if a potential purchase has these.

Prices for 330is tend to range from around £3000 for a very high-mile ropey example to about £11,000 for the last of the line low mileage face-lift machines. M Sports command higher prices than SEs and somewhere in-between our two price points you’ll find some gems – as ever it’s sorting the wheat from the chaff that’s the tricky part. Follow our guide to what goes wrong and you should be able to bag yourself a bargain sport saloon.


Given how the vast majority of car manufacturers managed to build a decent car body in the Nineties and Noughties, the previous E46 wasn’t good enough with arch rust as well as boot floor cracks where the rear subframe bolted in. The fact that the E90 was so vastly superior in this respect wouldn’t have been a reaction to these problems because design would have started just after the E46 went into production, but it indicated (as did the 2003 E60 5 Series) a new ethos of body design and paint techniques. That      means the E90 is a car that doesn’t really rust – you may find an early high mileage one (now ten or eleven years old) that has some cosmetic rust that has come from stone chips but even that is unlikely due to the galvanised panels and impressive undersealing. On the other hand, badly repaired accident damage using cheap pattern parts that haven’t been correctly rust-proofed will rust.

E90 door lock units can fail leading to a door that will either not lock on the remote key or not unlock, but fitting a new or good used one isn’t difficult or expensive. A new front door lock is £146 and a good used one is £45 plus they don’t need coding to fit.

Headlights need caution – standard Halogen units don’t cause any issues at all and are inexpensive both new and used, but anything Xenon will be an arm and a leg – the adaptive Xenons are an insane price (£1000) and the LED rear lights on LCI models are over £200 a side from BMW although aftermarket ones are a fair bit less.

Steering and suspension

Not much goes wrong here. Dampers rarely give any trouble and seem good for six figure mileages – new Sachs front dampers are around £170 for the pair from ECP whilst Lemforder front wishbones are £70 each – the E90 reverted from the old E30/E36/E46 single L shaped wishbone to four control arms, none of which are prone to wear. Rear coil springs can sometimes snap a coil off but again, it’s not that common compared to the E46 that used to eat them for breakfast.

The steering rack is hydraulic and not electric, but a new one from BMW is still the rude side of £1300 – make that £2500 if your intended buy has active steering, a rare option probably worth avoiding. A recon non-active rack is around £250 but you’ll be much better off with a good used ZF original – they rarely go wrong but good luck finding a used active steering rack, a system that also has a control unit and is linked into the DSC system via a (different) steering angle sensor. The standard E90 drives and steers so well that active steering isn’t really worth the bother and the fact that it’s such a rare options shows that new buyers thought the same.


The E90 was a big departure from the E46 and you’ll find most of them come with leather trim. Those with cloth will be the earlier SE models whose interior is the same as a basic 320d – functional but not exciting although an upgrade to leather won’t be expensive if you stick to nonsport trim – the black leather interiors are worth more than grey or beige.


The electric windows are okay and regulator failures aren’t as common as on the E46. Most of the issues that afflict the E90 we’ll cover next under ‘electrics’ but you need to go through everything and make sure it all works.

Transmission and drivetrain

The six-speed manual gearbox in these cars is an excellent unit that gives little trouble, and as such there’s not a lot to say about them – a good used unit is the best answer to any issues. A new LuK clutch kit is around £150 and the dual mass flywheel is pretty tough – unless it rattles, leave it alone.

The automatic gearbox fitted to the 330i is the good old ZF GA6HP that’s been around for over a decade, and a very good unit it is. These use the finned plastic sump with integral filter and at each service it should be inspected for leaks. These occur around the rubber gasket as well as the mechatronic plug sleeve and the answer is replacement of both parts using genuine parts only – do not be tempted to cut corners and use aftermarket parts no matter how Germanic the name as too many non-ZF plastic sumps warp with the heat and start leaking again. A genuine sump and filter kit with gaskets is only £166 from BMW and a new mechatronics sleeve around a tenner – it’s just not worth messing about so do it once, refill with the correct oil and all will be well.

Should you change the oil? It’s not worth a full flush, but a new sump/filter and oil every 50,000 miles is fine. Problems with the ‘box can be down to faults in the mechatronics unit such as worn sleeves for the valves, and a leaking bridge seal between the valve block and main transmission case can cause rough shifting. But overall, this auto box is a very good unit. Propshafts and diffs very rarely cause any trouble so again, it’s not worth elaborating.

The E90 is a great all-rounder and in 330i guise is a genuinely quick machine


Options on the E90 included sat nav with an iDrive controller and all of this needs to work. Often the controller won’t work when pushed down and whilst this can sometimes be cured by removing, dismantling and cleaning internal contacts, it often requires a tricky soldering repair.

These cars also have the steering lock with the ‘cassette’ type key that fits into the dash slot, although some cars have comfort access that doesn’t require the key to be inserted. Worn steering locks (ELV) can bring the yellow warning light on and you can either have the unit reprogrammed to accept wider parameters or if you’re friendly with your MoT man, remove the lock and cut off the locking pawl. That means no more steering lock, but less prone to ‘fail to proceed’ moments either. However it can be an MoT fail unless you explain the mod to the tester.

A red warning light is a no-start scenario. A new lock unit is expensive – it’s a circuit board controlled lock on the steering column assembly and as it wears, the ultra fine dust worn from the peg mixes with old dried out grease. This can lead to a non-start situation as the lock tells the CAS (Car Access System) unit that the lock hasn’t disengaged. Whilst it’s only for the skilled mechanic, the lock can be removed, cleaned up and regreased. However, cars with comfort access have another problem – a faulty door lock sensor can disable the steering lock and prevent a non-start…

Faulty LEDs on the tail-lights of LCI cars is common – they’re £220 new from BMW but half that from the aftermarket. The battery follows E60 practice in having an ‘intelligent’ control unit and as the life of a BMW battery is about eight years, many will be coming up to needing a new one. At the first sign of battery weakness have a new one fitted and properly coded – if you don’t you’ll have all kinds of issues.

Wheels, tyres and brakes

There are various wheel and tyre options on the 330i, but be wary of the 19-inch rims as the dreaded wheel cracking is still with us. Bent wheels can be straightened and often, cracked rims can be repaired but if you live in a town where the roads resemble a lunar landscape, chances are the wheel repairs will be a frequent occurrence – it seems BMW cannot believe just how bad UK roads are. Tyres are of course run-flats and whilst these gained a bad name for giving a grim ride, they are a lot better now to the extent that changing to standard tyres and carrying a spare may not be worth the bother – if you do, make sure you inform your insurance company.

Brakes don’t pose a problem – the discs and pads are cheap enough at less than £250 for Pagid parts whilst if you need a new calliper, they’re £93 each from Pagid. Where you can encounter serious expense is if you have a problem with the ABS unit. Sometimes the DSC valves can stick inside the unit, sometimes the ECU can go belly up. A new block is an unspeakable price (okay, it’s around £2500) and it comes with the ECU that on its own is just over a grand. There have been quite a few parts supersessions on these so a used one will need careful cross referencing by a BMW breakers such as Quarry Motors or FAB who have BMW ETK – normally a second-hand unit with the ‘wrong’ part number will work fine as it’s actually the same unit! No electronic handbrake nonsense on these either, just the same lever and cables system as before. An ABS fault can often be a rusted trigger ring on the driveshafts that has split. The official answer is a new £500 driveshaft but companies such as Quarry Motors as well as Reluctor Rings and various eBay suppliers can sell new steel rings for a fraction of the price – around 25 quid and two to three hours labour to fit per corner.

Servicing costs

The E90 is well catered for by both specialists and main dealers and these days, many BMW dealers are prepared to match or at least come close to some specialist’s servicing prices.

Type BMW Dealer Specialist
Oil Service £136 £115
Oil and microfilter £205 £170
Oil, microfilter, air filter and plugs £444 £360
Brake fluid £71 £70
Vehicle check £85 £70
Front brake pads £169 £120
Rear brake pads £165 £120
Service costs are from BMW UK’s website, plus specialist service prices taken from a cross section of specialists


The E90 is a great car to drive and the 330i is well worth the added fuel costs over a 320i for example. The auto version is a very nice drive and the manual a superb driver’s car reminiscent of the old E36 325i. Body rust is a thing of the past, but emerging mechanical and electrical issues mean that whilst the cars are reliable, any repairs are going to be pricey – they’re quite capable of swallowing a thousand quid to fix a seemingly minor issue and many early examples can be heaps that have been recently offloaded to avoid a large bill – make sure you dodge that bullet and only buy a nice one. 

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