When BMW E46 was first announced in 1997, many were wondering if it would be good enough to fill the shoes left behind by the E36. After only a few years of service, it has become apparent that the E46 was the next big classic from the 3 Series. Now that these cars are slowly entering their 3rd decade of service, you can go and find a really nice one for cheap!
However, you should definitely understand what issues and common problems these cars suffer from before you head out to look at any cars. We’ve put together a comprehensive list of issues and things you’d want to pay attention to when scoping a used BMW E46! Some of these are well-known problems, others not so much. Either way, you’ll be armed with all the information you need to make an educated choice!
1. BMW e46 Cooling System Failure/Leaks from Plastic Components:
The BMW E46 cooling system is full of plastic fittings, clips, and reservoirs that all have a habit of cracking, causing major problems with coolant leaks and De-pressurization. eEuroparts sells a kit to replace all the key failure points at once.
2. Weak Rear Shock Mount
In addition to reinforcing the rear sub-frame, the shock mount is another area that can use a little love. eEuroparts sells a part that reinforces the rear shock mounts, and it is straight from BMW. The rear shock mount reinforcement also fits E30‘s, E36‘s and Z3‘s as well, and fits on TOP of the mount on the interior of the car. The original design focuses on the bottom of the mount, where the weight of the car sits but has no emphasis on the top. This makes unloading the suspension potentially hazardous to the other side of the shock tower.
If you are doing a rear shock mount, there’s no reason NOT to bolt on this reinforcement. Because of this, we sell the shock mounts, gaskets, nuts, and reinforcements together as a kit. This will beef up your suspension mountings and let you focus on other areas of the car. For a little more money, we offer fully reinforced versions for 10mm and 12mm shock shafts. The 10mm shaft versions would be for OE style shocks, where the 12mm versions would be for cars that have externally adjustable mechanisms such as Bilstein B8’s. The extra width would be to accommodate that linkage, you should know if you have installed a larger shaft shock absorber.
3. Tail Light Failure
An intermittent ‘tail lamp out’ indicator on your dash could mean a few things, but hands down the most common failure involves the circuit boards inside the taillights. This is so common that we made a complete kit to replace your components with uprated parts, including a wiring harness that is more capable of handling the heat and current of normal usage. The surprisingly cost-effective kit (100k10107 BMW Tail Light Repair Kit (E46)) includes new Genuine BMW taillight circuit boards for both sides of the car (63217165865 and 63217165866), as well as a Genuine BMW wiring repair kit. We also offer the connectors and the corresponding terminal pins in case yours is melted, which is common.
4. Crankcase Vent Valve Failure/Maintenance:
The PCV (Positive Crankcase Ventilation) system is meant to separate the oil of the oily stirred up the air that pressurizes the crankcase of the engine due to piston blowby. The hoses and separator, therefore, see a lot of action when it comes to hot oil, which can build up inside and cause problems. Due to this, the PCV system should be considered a maintenance item and replaced regularly to prevent sludgy buildup from clogging oil vent passageways.
A sure clue of clogged or constricted PCV components is that the seals around the crankcase will all start weeping oil due to the pressure that is not allowed to be vented. This includes the timing cover, oil pan, and especially the valve cover. We have kits and parts for the M54 and M52 6 cylinder engines found in the BMW E46 3-series.
5. Torn Front Axle Boots / Front Axle Failure (Xi AWD models only):
The front axles on these cars are notorious for having problems, specifically with the CV joints and related boots. These problems are accelerated with lowered cars, so it’s important to pay attention to the CV axles on your all-wheel-drive model. If you catch it early, you can get away with just replacing the boots. The boot isn’t super easy to replace because to do so, and you must remove the axle. However, replacing both axles at a dealer will run you more than $1700. Replacing four CV boots (each axle has an inner and an outer CV joint) will cost under $100 and a few hours. The CV Boot numbers are 31607507402 for the outer (the more common to fail), and the inner is 31607507403.
If the boot has been torn for a while, there is a high probability that the joint has run dry and been contaminated with dirt, grit, and road grime. In this case, the tight tolerance joint wears out quickly, and the entire axle will need to be replaced. We have front axles available for the E46. The high-quality GKN front axles for the BMW 325xi and 330xi are 31607505199A for the front driver side and 31607505200A for the front passenger side.
6. M3 Camshaft Gear Bolt Failure (S54 only)
The S54 engine has been known to have the cam gear bolts break. It is recommended to have these replaced every 30,000 miles at the same time as the valve adjustment. If one or more do break there would be catastrophic engine damage. We sell all the necessary hardware, that comes with the necessary Loctite® thread locker.
7. Engine Oil Filter Housing Gasket
As with many soft engine gaskets, the oil filter housing gasket is a common failure point. This gasket will harden over time from the heat cycles produced by the engine and oil contaminants causing it to leak. If you see oil on the driver side portion of the engine block near the oil filter you know this gasket is leaking. Depending on the size of the leak, this may also cause the low oil light on the dash to illuminate. We have seen instances where this leak will cause the belt to slip off and jam into the main seal behind the crank pulley.
8. Rear Sub-frame Bushing Failure
As mentioned above, the rear subframe takes a lot of abuse in these cars from lateral movement. Besides the subframe itself, the bushings take a ton of abuse and subsequently wear out. When the bushings wear out, it will cause clunking and banging, and accelerate wear on the subframe itself. Aside from the subframe reinforcing, it’s a good idea to make sure your bushings are all fresh to keep the car from hammering and banging itself apart. The key bushings to look at here are in this kit we put together, 100K10187.
9. Rear Spring Failure
The rear springs are notorious for breaking on the bottom coil, where it sits on the control arm. This is due to the fact that water and road salt will collect in this area and corrode and weaken the steel spring causing it to break as it compresses eventually. The rear springs for rear-wheel-drive models are 06165. The rear springs for the all-wheel-drive models are 06254. Springs can be tricky sometimes, so if you have any questions don’t hesitate to contact customer service (800) 467-9769 or email them here.
10. Driveshaft Flex Disc / Center Support Bearing Failure
Driveline vibration which can be felt through the body of the vehicle may hint at a worn flex disc and support bearing on the drive shaft. The main function of the flex disc is to absorb vibration and as this item wears it transmits those vibrations throughout the chassis of the vehicle. If left un-repaired, the disc will actually start to tear and can damage the pinion flange on the differential. Worn center bearings will heat up and bind which will prevent the drive shaft from rotating freely, and can cause catastrophic failure.
Rear wheel drive vehicles will use Center Bearing 26127501257 and Auto Trans Flex Disc 26117511454, and we’re also selling the kit. Manual Transmission cars use Flex Disc 26111227410 and that kit is 100k10242. All-wheel-drive vehicles will use Center Bearing 26121229317 and Flex Disc 26111229360, and the kit for these cars is 100k10243.
Owning a used E46 is an awesome experience, and we’re standing by to help you keep it that way, every step of the way. It’s no secret that E46 has a special place in all of our hearts here at eEuroparts. Our stocks of BMW E46 parts are always topped with fresh products so that even if your new Beemer runs into trouble, we’ll be able to get it up and running in no time.
Check out of parts for this model and enjoy the best prices around! If you have any questions or can’t find a specific car part, reach out to us and we’ll get you taken care of to the best of our abilities. At the end of the day, it’s all about keeping another E46 healthy and on the roads!