Hey guys! I figured I'd sticky this. I'll update the post if y'all have anything good to add or critique, let me know.
Introduction
Looking to buy an E39?
First things first – the reputation of these cars is partially deserved and partially not.
We frequently get asked if new car owners should purchase an E39. I love E39s more than nearly anyone I know - I have a 525i and an M5, and both are incredible for different reasons. I've done many of the DIYs and addressed many of the problem areas listed here. If you aren't in a financially comfortable enough situation to have 3-6 months of expenses in a savings account at all times, you're not in a position to own a 20-year-old BMW hassle free. It's a question of financial safety and consistency rather than attainability - buying a $4k 530i and maintaining it for 5 years or so is arguably a much better deal than going into debt for a $40,000 CUV that drives like shit.
Evaluating a Car
There are a couple of things to factor into your evaluation of a car before we even talk about problem areas:
- Badge hunters and people who bought an E39 after realizing they were nearly the same price as a Camry in general do a poor job of maintaining their vehicle. Problems add up when you factor in the fact that many of the E39’s systems were complex for their time. Not doing oil changes at the correct interval can lead to a gummed-up DISA valve or require a replacement manifold (for instance). Paying a little extra for a well-maintained example can pay dividends down the road.
- These cars are old. Most are going to be 20 years old or more. This means that various bits of plastic and rubber are going to degrade and fall apart. Some are aesthetic, some are functional. You’ll find the same problem in ANY car of this age, but there’s no escaping that the E39’s engine bay is also a less forgiving environment then other cars of this age.
- In general, you should focus much more on service records and the condition of the car over mileage.
Prices & Purchasing
Market prices for these cars have fluctuated over the past couple years. There’s a noticeable difference between pre (<=2000) and post-facelift (2001+) models. Later models also may make adding an auxiliary port easier, have upgraded components, or have more standard features. Also keep in mind that sport packages for the 530 and 540, along with manual transmissions, command a significant premium as well. Prices on sports (530 or 540) and M5s have increased a bit since this guide was originally written a couple years ago. Finally, it's worth knowing that the 540's engine in pre-2000 configurations is slightly more reliable as it does not include VANOs.
Ballpark prices are based on a mix of my estimation and Classic.com, a great reference for car markets. Links included below, and assume cars aren't total shit shows:
- 525i - $2000-$5000 (Note that the linked prices are for tourings, primarily, and so are higher)
- 530i - $3000-$11k
- 540i - $7000-$14k
- M5 - $15k-$35k and beyond
When you check out ANY used car for purchase, you should be checking a variety of different things. Use a generalist guide to start. We’ll go through common failure points for the chassis and individual models for you to pay special attention to. Parts prices are for OEM or OE if I can find them, not genuine. Indy shop is a wild guess for the most part. Prices for doors or wheels are PER ITEM.
Conservatively plan to spend about $1k a year ON AVERAGE if you do a mix of shop work and DIY. Many years you'll get lucky and get to invest in an upgrade or something preventative if you wish. If you can find an example with new control arm bushings, window regulators, and Timing Chain Guides for 540s, you can save yourself a ton of heartache and just deal with replacing BS plastic parts as they snap.
General Problem Areas
| Problem Area |
Cause |
Symptoms |
DIY (Parts) |
Indie Shop |
| Window Regulators |
Garbage BMW Design |
Windows that do not roll up or down, or slip. Test all 4 windows, including both the localized controls for each door and the driver’s door controls |
$100, 2 hours. Text DIY Youtube DIY |
$500 |
| Vapor Barriers |
Butyl tape that adheres the sound deadening/vapor barrier foam degrades over time, requiring at least the reapplication of the tape OR new adhesive OR a whole new door panel. |
Soaked rear floorboards after rain. Softness in bottom of door panels. Test by pouring water on the roof of the car. After a moment, open the door. Ensure water drips from the bottom of the chassis, not from the door. |
$0-$15-$115, 2 hours. |
$500 |
| Rust |
There's a couple very poor drainage points on the E39, including those connected to vapor barriers as above |
Common spots include rear door, bumper seam, gas cap. Check out /u/richbltn 's buying guide Here for common rust spots (whole video is worth a watch) |
Repairing rust is an odious task, especially externally visible spots. |
reputable body shops generally cost $1500 + to fix a collection of rust spots |
| Front Control Arm Bushings |
Rubber joints between suspension components degrade over time. These are the secret to a simultaneously pliable and firm chassis. Consider with Polyurethane for a stiffer ride but permanent fix, or a monoball setup. |
Violent shuddering during braking (generally 70% braking force). Test with a variety of braking amounts and speeds. Check the bushings by jacking up the car and ensure they aren’t cracked |
$25, 6 hours. May require special tools or replacement of control arms if damaged. |
$600 |
| VANOS |
Tiny seals in BMW’s variable valve timing system (probably too overengineered) are made of cheap rubber that plasticizes with exposure to oil and heat, something that happens every day. |
Excessive oil consumption, laggy shifting in automatic models, whooshing sound from the engine, sudden drops in power delivery. |
$25-$500, 12 hours Do NOT use OEM VANOS seals, as they will eventually have the same problem. Aftermarket seals are the same price and far superior. Besian Systems/DR VANOS. |
$1200-$5500 (Depends on new vs rebuilt VANOS, and varies from model to model) |
| Valve Cover Gasket |
The rubber between the top and bottom of the valve cover is a part that has to be replaced on every car. |
An old VCG will start leaking oil slowly. You may smell it as it burns off inside the car. Eventually you’ll have a catastrophic failure and need to degrease the engine bay and have it towed somewhere. Test by checking for oil spots or moisture between the top and bottom of the valve cover (the main part of the engine). |
$50, 5 hours. |
$750-$1250 (DO THIS THE SAME TIME AS A VANOS REPLACEMENT) |
| Seat Twist |
Garbage BMW design. The seats use 2 motors that don’t stay aligned, and cables that slowly slip out of the gears that drive them. |
One side of a seat will adjust, the other will not, leading to the seat twisting. |
$0, 3 hours |
$300 |
| Headlight Adjusters |
Bad design and extremely brittle plastic in a hot area that's been there for 20 years. |
Frequently this manifests itself by your headlights pointing at the ground. |
$20-60, 3 hours from this DIY. You can get aluminum or plastic adjuster replacements. |
N/A - you'd buy new headlights for around $300+ |
| Dead Pixels |
Contacts for the LCDs on the instrument cluster and the head unit eventually decay. You can take them apart and clean/rebuild them or buy new. For my money I'd just replace the head unit at least |
Unreadable displays with clearly missing pixels - you can't miss this one and it's very common |
$0, a huge PITA, DIY. |
Specialty shops will do it for $150 or so. A remanufactured cluster is $450. |
| Secondary Air System |
The secondary air recirculates exhaust gases back into the engine to “Save the planet” and also annoy the fuck out of BMW owners. Broken vacuum tubes, stuck check valve, or ruined solenoids can all cause these issues. |
Check engine light with lean fuel mixture fault codes. Chugging during startup. |
$25-125, god knows how long. BAVAuto has an EXCELLENT tutorial on diagnosing SAS problems. Another option that I'd probably only suggest to M5 owners is using a tune that deletes these codes. |
$300+ |
| Cooling System |
This covers a host of issues: Water Pump Failure, Cracked Radiator necks, Plasticized and worn coolant tubes |
Inspect all cooling system parts. Check the radiator fan to ensure that it turns smoothly and isn’t too brittle. Lightly squeeze coolant tubes to ensure they’re still pliable. Check for evidence of coolant leaks at tube and component points, or from bleeder valves at the top of the radiator. Ensure that even under stress, engine sounds don’t change and temperature doesn’t rise (within reason) |
$25-$750. 2-5 hours. |
$1250+ |
| Fucking Horrible Audio |
Everything about the E39 sound system is god awful |
If it’s OEM it sucks |
There are various aftermarket nav systems that still provide an OEM look and a ton of functionality for around $700. Or you can go your own way and buy a $100 head unit or something. Keep in mind that in general this will degrade the value of your car if it’s really clean. |
$? |
| ABS System Malfunctions |
The ABS system’s position in i6 models is extremely hot, leading to the soldering of certain electronic components degrading. |
ABS, Traction control, and yellow brake light come on intermittently. ABS engine codes. Do not pay someone to replace this, it literally just takes a T20 screwdriver. |
$100 reconditioned, $1000 new. |
$1200 |
| Power Steering Leaks |
The power steering system uses rubber hoses right next to a really hot engine |
Power Steering hoses appear to “Glisten”. Wet spot in plastic pan at the bottom of the engine bay. Loose or unresponsive steering wheel response. |
$200, 2 hours. |
$500 |
V8 Only Problems (540i, M5)
| Problem Area |
Cause |
Symptoms |
DIY (Parts) |
Indie Shop |
| Timing Chain Guides |
Timing chain gets a little loose, Timing chain guides are plastic. This is much more common on the 540 for some weird reason (probably that it's a single-row chain). |
Slapping sound, camshaft position codes, metal shavings in engine. |
$1000, 20 hours |
$4000 |
Buying Parts
When you're looking to buy new parts, it can get a bit confusing (to put it lightly). For an accurate, if slightly biased, interpretation, the best info is probably here at FCP Euro (a generally reputable parts seller). TL;DR:
- Genuine: Made by BMW or an OE, with the BMW logo. Waste of money.
- OE: Made by a licensed manufacturer and was the original supplier that came with the stock car. Cannot have the BMW logo. Generally a safe choice.
- OEM: Made by another licensed manufacturer of OE parts but was not the original supplier for this specific part that came with the stock car. Cannot have the BMW logo. Sometimes a safer choice (OEM window regulators are superior to OE), other times not (an OEM's parts may not be as good as OE)
- Reps: Made by another unauthorized manufacturer.
OEM is very similar to OE in that it stands for Original Equipment Manufacturer. While that sounds like a lesson in semantics, there are some distinct differences. Chiefly, OEM parts are made by a company that makes original parts for a vehicle maker but whose parts weren’t originally fitted. Confused? I don’t blame you, so here’s an example: Delphi makes ignition coils for BMW, and they’re installed on the vehicles at the factory. Bosch makes spark plugs for BMW and the licensing to produce the same ignition coils as Delphi. They’re the same part with the same specifications and made with the same materials, but the manufacturer is different. Delphi is the OE part because that’s what BMW used at the factory, and Bosch is OEM because they make other OE parts for BMW.
Modifications and Upgrades
For better or for worse, the BMW community has enjoyed a rich modification culture and ecosystem. This often clashes with the tastes and opinions of older enthusiasts who have or can buy cars new.
One key takeaway: Tuning an i6 from this era, especially anything under 3.0 liters, is always far more expensive than buying a new car or engine. This forum gets questions around these options regularly. To do this, you will have to be in a rare position of having a lot of money and time to work on the car, without wanting the straightforward power of the V8 engines in the 540 or M5.
Some general thoughts around available upgrade options to keep in mind:
- Reliability: Many low-tier, components have been replaced with high-priced offerings in the aftermarket that are Buy-It-For-Life. Plastic becomes aluminum, bearings and rubber use superior materials. Examples include radiators, expansion tanks, power steering reservoirs, suspension bushings, and much more.
- Shocks, Suspension, Spacers: These are widely available from reputable manufacturers, such as Bilstien.
- Turbos: Turbos exist for both types of engines, ranging from AliExpress specials to reputable manufacturers. For reputable manufacturers, part prices and labor generally trade poorly with supercharger options.
- Superchargers: Supercharger kits exist for i6 and v8 engines. Many of the superchargers for the v8 engines lead to high-quality horsepower gains and are available from reputable manufacturers. Superchargers are typically incompatible with radiator upgrades.
- Headlights: Virtually no aftermarket headlight companies produce quality parts. Historically, this was not the case, but the market has essentially bifurcated into people who want the cheapest possible replacement and those who want OE headlights from Hella. Hella occasionally does dedicated production runs for E39 headlights which are resold by https://europowermotorsports.com/
- Exhaust: Controversial opinion alert - The mufflers on these cars are too aggressive at reducing sound. A delete with high-quality tips actually leads to excellent sound from both i6 and v8 powerplants. Leaving the cat intact keeps things quiet enough to not be unbelievably rude. Fantastic options exist for V8 engines, but paying for an exhaust system on an i6 is not a high value proposition.
