Troubleshooting BMW E34 5 Series Common Problems

“This month we focus on the E34 5 Series, built between 1988-1996. Here’s everything you need to know about their common issues and problems”

Troubleshooting BMW E34 5 Series Common ProblemsCome 32-years have now passed since the E34 5 Series went into production to replace the E28, itself a development of the 1972 E12 model. The E34 was a clever amalgamation of new and old parts, a handful from the E28, plenty from the 1986 E32 7 Series and a lot of new parts as well. Considered by many to be the best 5 Series, it’s certainly a classic now with prices on the rise as the number of good ones fall.

Launched in 1988, the initial range of saloons comprised the M20 engined 520i and 525i (129 and 171hp), plus the M30 530i and 535i (190 and 218hp). Standard fi ve-speed manuals and optional ZF four speed switchable autos. The 24-valve M50 replaced the M20 in 1990 with the 150 hp 520i and the 192hp 525i replacing the M30 530i as well. Touring estates and the 525td and tds diesels with 115 and 143hp arrived for 1991, and 218hp and 286hp 3.0 and 4.0 V8s arriving the year after for the new 530i and 540i – both with five- speed automatics with a six-speed manual no cost option for the 540i. The economy 518i arrived for 1990 with the M40 four, replaced by the chain-driven M43 for 1994, both delivering around 115hp. Saloon production ended in 1995 and the Touring in 1996 after sales figures pretty much doubled those of the E28. The E34 went through its banger phase years ago but plenty are still in a ropey state, and to use one every day they are pretty maintenance intensive.

Having said that they are far easier to work on than the later E39 with simple electrics and suspension. The 525i 24v is probably the best all rounder with the 520i following it – not fast but they go fairly well with the five speed auto version being pleasant to drive.

Owning an E34 is a labour of love and it’s at the stage now where it’s worth starting to collect good used parts whenever they appear; instrument clusters, ECUs, wings, headlights and any new old stock consumables like dampers, exhaust boxes and so on. The E34 is still good enough to use everyday and the ride, refinement and solidity will still impress you – these were built to last indefinitely.

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Troubleshooting BMW E34 5 Series Common Problems RustRust
E34’s are now old enough to be well and truly ripe – most have either had welding or are in need of it. Rear sills issues are common, later cars with plastic sill covers being especially prone to rot. Front jacking points are hot spots now, lifting the carpets can often reveal a horror show. Cosmetic rust is common but new pattern wings are available as are good used doors. Keep in mind that the doors changed in 1991 but they can be altered to suit earlier cars.

All E34s use a steering box that works very well when in perfect condition. A lot of steering box wear is actually play in the steering column adjuster – nipping-up the 32mm nut by the pedal box can remove a lot of play. Steering box adjustment needs care as it’s easy to over do it and cause binding in the box. Replacing the complete track rods is better than just the ends. Tourings with self-levelling use Pentosin fluid and not the usual red ATF.

Troubleshooting BMW E34 5 Series Common Problems SuspensionSuspension
The E34 is quite a heavy old bus and it’s hard on its suspension. Having said that, everything is available from good suppliers such as febi Bilstein and Lemforder. Upper and lower front control arms, drag links, dampers and rear axle bushes are all common casualties. Beware of rotten rear spring cups – these rot away under the spring’s lower rubber cushion. Be aware that there are four different types of front damper and top mount; big and small top mount, thick and thin top damper pin.

Automatic Gearbox
A lot of these are coming to the end of the road with the old 4-speed ZF being a bit fragile now. Manual conversions are a good plan, and good used 4HP22 auto boxes are now rare – most used ones are not far behind the one you’re changing. Rebuilds are $1.911 or so. The later five-speed is a much better unit, and there are plenty of good used ones about, but 530i/540i ones are rare. 518i and td diesels use a four- speed General Motors box that is not a bad unit.

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M30 Engine
A bigger version of the M20 but with a chain for the camshaft. Cam wear is common thanks to those daft banjo bolts – fit new BMW ones every time you adjust the tappets as they’re only a few pounds. Head gasket issues were never common but the M30 isn’t an easy engine to work on, a top-end rebuild is expensive and time consuming. Regular oil changes and tappet adjustment is the key to a long life, and new coolant every two-years.

M20 Engine
These are now pretty ancient with very few left. The 520i was a gutless wonder and the 525i isn’t so lively by modern standards, however it’s not too sluggish. Camshaft wear and heads that develop a hairline crack (oil and water mixing) under the cam journals was common but there are still a few good used units about. Change the belt, tensioner and water pump every 30,000-miles. The Motronic 1.3 engine management is pretty good but new genuine crank sensors are getting hard to find.

Troubleshooting BMW E34 5 Series Common Problems M60 EngineM60 Engine
The V8 was a big step up over the M30; more compact, powerful and economical. Regular oil changes are key but there are other things too; the breather at the back of the inlet manifold needs changing regularly, the oil pump bolt torque checking (easy once the front sump is removed).. Early ones used Nikasil bores but if it idles smoothly and doesn’t smoke, it’ll be okay. The block casting numbers are very hard to see but they are: 1725970-1714212 M60 B30 Nikasil, 1745871 M60 B30 Alusil, and 1725963 /1742998 M60 B40 Nikasil and 1745872 M60 B40 Alusil.

M51 Engine
This old diesel was a chain-driven lump, intercooled on the tds and not on the td. With regular oil changes they’re not a bad old thing; cold start problems will be the in-tank pump, the O ring where it fits into the plastic cage in the tank, or the fuel pump relay. Some owners have powered the pump directly from the ignition switch to aid cold starting. The M51 rarely goes wrong although ambitious remaps have resulted in con rods making a bid for freedom. These can run on vegetable oil, turbos are robust and easy to replace. Economy isn’t that great though.

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M40/M43 Engine
The 518i unit is normally a tough old mill. The M40 can suffer cam wear due to a blocked spray bar but it’s easy enough to fit a new cam and rocker set with the head still fitted. Change the cam belt and rollers every 30,000-miles. The M43 is a better engine but they are known for a head gasket failure, changing one is a nice simple job – remove the head, skim it and reassemble with loads of room to work.

Many Tourings (but very rarely the 518i or 520i) used SLS self- levelling suspension, it’s usual to find a set of rusty old pipes and leaking dampers here – note that the setup can be changed to standard suspension. SLS was great when working but replacing the pipes and dampers is very expensive and time consuming. Conversion requires a couple of standard rear struts, removing the pipes and fitting a standard PAS pump

Troubleshooting BMW E34 5 Series Common Problems Cooling SystemCooling System
Unlike later BMWs the E34 cooling system is very robust. Most water pumps are easy to replace, but change the M20 pump with the cam belt. M50 and M30 ones are very easy. A leaking heater matrix isn’t hard to replace on non-air-con cars (glove box out) or those with factory A/C (center console out). Some cars have an electric coolant pump for the heater, it’s best binned when it starts leaking

All E34s can suffer wiper spindle wear. New wiper racks are expensive so it’s worth buying a worn one and having new brass bushes pressed in. In-tank fuel pumps can fail suddenly but they’re easy to change – it’s worth keeping a new one in the boot. Instrument panel pixels last longer than on E38/E39s, the 518i/520i and diesel clusters can suddenly die. Apart from early base model 518i and 520i cars, E34s have pretty reliable body control modules under the rear seat.

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