BMW 1 Series diesel. Andrew Everett offers his essential, Top 10 buying tips for those searching the classifieds for a first-generation 1 Series diesel.
Trouble-shooter Down-to-earth advice on buying an early 1 Series diesel
Since it arrived in 2004, the hatchback 1 Series has been a tremendous success for BMW. It defied the many doubters and outsold the previous Compact handsomely. Here we’re focusing on the original model, that ran between 2004 and 2011; the BMW E87 (five-door), BMW E81 (three-door) plus the rarer BMW E82 Coupé and BMW E88 Convertible. The overall view is that they’re generally very good cars, however, there are a number of pitfalls to avoid when buying, so read and digest before beginning your search!
The 118d (until mid-2007 and the advent of the N47 engine) used the small-casing, Type 168 differential; a higher-geared version of the same diff’ used in the four-cylinder petrol cars. These units relied on ball bearings for the pinion and diff’ carrier, rather than the previous, taper roller bearings and, generally speaking, they weren’t really up to the task. A whining noise indicates that the diff’ is in trouble but, rather than trying to find a good used one, fit a 120d diff’ (plus 120d driveshafts and propshaft) – problem solved!
Later, ball bearing-based diffs weren’t really up to the job; whining is a common problem to watch for.
When it was brand new, the BMW N47 was a marvellous engine – powerful, economical and quieter than the previous unit (M47N). The fly in the ointment, however, was the rear-mounted timing chain that suffered many issues. It’s a very simple chain and tensioner design, and nobody really knows why they are so troublesome.
Chains can break, causing extensive damage – even a low rpm, valve-to-piston collision can twist the cam lobes around on the tubular camshaft, rendering them scrap. It’s a £1,000 job to replace the lot, so make sure you check for chain noise. Crouch down by the driver’s door and listen carefully for a distinct ‘shhshh-shh’ sound.
REAR WIPER ISSUES
The 1 Series continued the previous 3 Series Compact tradition of a wiper motor whose central shaft was hollow – washer fluid passes though it and out of the nozzle. However, with age, these can start leaking fluid into the motor, causing corrosion and eventual seizure.
Fitting a replacement is quite simple, with new motors costing about £120. But a good, used one (maybe even a recent BMW replacement unit) can be found for around 40 quid. Non-working washer? Remove the central nozzle jet and poke it through; chances are the hollow shaft is blocked. The plastic washer nozzle can get bunged-up, too - does water shoot out with the nozzle removed?
New wiper motors cost about £120, while good, secondhand units are available for well under half that price.
BMW pioneered the idea of hiding the washer bottle between the front, off side wing and the inner wing, behind the wheel arch liner, on the 1 Series. There are filters on the washer pumps (one front, one rear), and these can clog-up, meaning that the whole washer bottle needs to be removed, emptied and thoroughly cleaned out (including the small, plastic filters).
It’s an annoying job, requiring quite a bit of fiddly dismantling, and is best tackled on a free day in the summer, rather than as an ‘emergency’ fi x during the winter.
The shape of the washer bottle (long and thin) means the washer fluid is prone to freezing in a bad winter – keeping it almost empty and adding warm water with screen wash mix when needed avoids this.
Although a fairly rare problem, failure of the BMW badge boot-opener on the tailgate is an annoying one. These can get really sticky, and the micro-switch inside can break. But they’re easily maintained with a pre-winter shot of penetrating fluid and spray grease. If a replacement is needed, a good used one will cost you 20 quid or so from eBay, and fitting is simple. With the tailgate trim panel removed, it’s just three Torx screws, an electrical connector plug (there’s no direct, mechanical link to the boot latch) and it twists round and pulls out – fitting takes 20 minutes. If the boot won’t open (even using the key) then fold the rear seats forward, open the small plastic panel on the tailgate trim panel and flip the red emergency knob sideways.
The tailgate release mechanism can give trouble but replacements are cheap to buy and easy to fit.
The 1 Series isn’t prone to these, but the four-cylinder cars did have a known problem with the ABS control ECU. BMW brought the price of new ECUs down to well under £200, but they’re not easy to replace. The whole ABS unit must be removed, the brake lines disconnected and the system bled afterwards.
With a rear ABS sensor fault, it’s likely the steel ABS reluctor rings of the outer CV joints have split, wiping-out a sensor. Older BMWs had slots machined into the CV but later, steel serrated rings were shrunk onto the CVs. The joint corrodes and the expanding rust splits the rings. Removing the driveshafts and fitting new rings (£30) isn’t a bad job.
While the 118d cars generally didn’t have these, the 120d models do. They are improved over the old E46 set-up, and they can’t really fall into the cylinder anymore. Ideally, though, the manifold should be removed, the swirl flaps binned and the alloy blanks fitted.
N47 cars have a different set-up, but these can also cause problems nowadays, so remove them, together with the operating shaft. But, as with the previous M47N engines, keep the actuator fitted and plugged in, otherwise it’ll probably trigger a fault code.
ELECTRONIC STEERING LOCK
All cars have an electronic steering lock, operated by the key plugging into the slot in the dash. There is no mechanical connection at all and, with age, the lock can start to malfunction – the orange, steering lock warning light tells you to get it looked at immediately, and the red one tells you the car is going nowhere.
Very often, all that’s needed is to use diagnostics to reset the counter (it records how many times it’s been activated) but, often, parking with the steering wheel at an angle and stressing the lock, will cause the orange light to come on. So always park with the steering wheel ‘loose’, so the lock pawl isn’t under any strain.
All first generation 1 Series diesels are fitted with an electronically-operated steering lock. Problems with this will trigger an orange or a red warning light on the dash.
Exhaust gas recirculation was a system designed to improve emissions by piping some of the exhaust gas back into the inlet. This is all well and good in theory (it also lowers combustion temperatures) but, in practice, it can really clog up the inlet.
When you have the inlet manifold off to remove the swirl flaps, you’ll be amazed at how much black tar you find in there. Clean it all out and get the EGR valve cleaned as well. I’d EGR bypass; just clean the valve out every couple of years.
These cars also have an EGR cooler with its own, small thermostat. If this gets stuck open, then the EGR will run cool, making it less efficient, and adversely affect fuel economy, too.
You’ll be amazed how much EGR-related muck you can find inside the inlet manifold on highermileage cars.
All manual cars were fitted with a dual-mass flywheel and, by 100,000 miles, these units can be on their last legs. Drive it with a rattling flywheel and, chances are, the crankshaft will snap eventually.
Don’t be tempted by a solid flywheel conversion either. Clutches and gearboxes are generally OK, but the late cars – with auto stop/start – can have trouble with syncros and, if you need to source a secondhand gearbox, be aware that they’re expensive and hard to find. You’ll need the exact part number, too, and can recognise a stop/start manual ‘box by the plastic sensor on the top of the casing, near the bellhousing.
Dual-mass flywheel wear issues – highlighted by rattling – must be dealt with before serious mechanical damage is done.