BMW 3-Series E46 Common Problems And Solutions


The BMW E46 is a high-performance German sedan/coupe that is now coming down in price to allow it to fall into a completely new market.  Offering great bang for the buck, it’s important to realize that a car built to these tight tolerances requires quality maintenance to avoid major headaches.  Here’s a list of the BMW E46 Common Problems, so you can keep in mind probable repairs you may have to accomplish during ownership of an BMW E46 3-series.

1. Cooling System Failure/Leaks from Plastic Components:

The 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, and includes genuine BMW coolant to flush the system when done. The number for the eEuroparts.com BMW E46 3-series cooling system refresh kit is 100k10097.

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- 100K10157. This will beef up your suspension mountings and let you focus on other areas of the car.

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 tail lights. 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. I wrote a DIY blog on the subject, which you can read here [click here]. 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 (61129281435). We also offer the connectors (12527519956) and the corresponding terminal pins (12521433217) 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 out of the oily stirred up 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 in order 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 two kits for the M54 and M52 6 cylinder engines found in the BMW E46 3-series. They are 100K10104, and 100k10237 for cold climates. The second kit features insulated hoses to prevent water condensation from contributing to sludge buildup.  You can read the DIY blog about this here: [click here]

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 in order to do so 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 of time. 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 two front axles available for the E46 AWD, a cost effective Empi as well as a higher end GKN axle. The Empi numbers are A807916 for the front driver side, and A807917 for the front passenger side. The 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

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 a kit with all of the necessary hardware, 100K10240, that comes with the necessary Loctite® thread locker.

7. Engine Oil Filter Housing Gasket

As with all gaskets, the oil filter housing gasket, part# 0816965, 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.

8. Rear Sub-frame Bushing Failure

Like 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 sub frame 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 eventually break as it compresses. The rear springs for rear wheel drive models are 06165. The rear springs for the all-wheel drive models are 06254.

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 the kit is 100K10241.  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.

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30 thoughts on “BMW 3-Series E46 Common Problems And Solutions
  1. Richard Folke

    How about the inside door / window moldings (the fuzzy ones) that fall off on the E46; or at least on my M3? Do you have replacements or advice on re-attaching them?

    • Eric Hirschberg

      It’s hard to tell what you are describing, but both the door seal and the window seal hold themselves in place. The large rubber door seal pushes into a groove and is held in with a flexible adhesive. The window guide appears to be held in place by its own guide rails, but hard to tell for sure. If you would like to send customer service an email with a clear photograph, they will be able to help you quickly to find the right replacement part. Chances are, you will be unable to simply glue the parts back as a permanent solution, because the reason plastic and rubberized trim pieces fall off in the first place is due to the material composition changing from expanding and shrinking, drying out etc. We will be able to get any piece of trim you need, let us know, and thanks for checking us out.

  2. Thanks for the information! The drive shaft in my car hasn’t been working very well, so I need to have it replaced. It’s a good thing that you included the parts that my car would need to have the right drive shaft. The drive shaft between an automatic and a manual are different, so I’ll make sure to get the replacement part that I need for my manual transmission.

  3. Lee

    I have a BMW 320 diesel tourer 6 speed the intercooler pipe keeps blowing off I changed the intercooler got a new pipe and clip and is still blowing off has anyone came across this before and why this happens thanks

  4. Paul adams

    I have a 330i touring. My alarm keeps going off. It’s not the movement sensor this I do know. Neither is anything left open, like the tail window!!!. Is there anything common in these that anyone knows of?

  5. Thanks for Posting a Nice Post! I have also problem in BMW. But I resolve this all. Some things I repaired. Some are changed. Now working well. Everything needs care and maintenance for work properly.

  6. william higson

    Hi, I am looking at a 2001 325i E46 manual with 100000 kms on the clock. I have read you comments about common problems and would expect to upgrade the parts over time. I live in Qld. Australia and would like to know your shipping costs. Cheers,Bill.

  7. Anthony Mwithaga

    Good evening. My name is Anthony Mwithaga from Nakuru, Kenya. I own a BMW e46 m52, 323i, 1999 (chassis no. NC00548). I need to know how much I can get a universal joint lower, rear vent, ABS pump, 2 front window mechanisms.

    • Adam Goral

      Hi Anthony, http://www.realoem.com/ this is a great website to help find specific part numbers, I think it may be easier this way for you. Unfortunately due to high levels of fraud we do not ship to Kenya, but if you can find a company that does, finding the exact part numbers will help you immensely so there are no language barriers to deal with. You have the chassis number already which is a great start, good luck Anthony.

  8. Tich

    HIie,I am Tich from Zimbabwe. I have a BMW 320i e46 2001 MODEL 55000KM. Its loosing power when driving as if am pushing it too hard and high revs with less speed. What might be the problem?

  9. Lorraine

    Hi I’m driving a 2004 320D BMW. When I start the car it is just white smoke. The car still got power. What could it be

    • Adam Goral

      White smoke can indicate burning coolant, the most common culprit is a leaking head gasket allowing coolant to get into the combustion chamber. Keep an eye on your coolant level, if it stays the same then it’s more likely that condensation steam is making it out of the tailpipe when it’s cold. This is common for diesel engines and you shouldn’t worry.

  10. Jude rassie

    Hi my name is Jude from richards bay South Africa I have beenoffered to exchange my land rover disco 1 1997 model for an e46 325ci coupe good or bad deal

    • Adam Goral

      While the Discovery is more capable and has more ground clearance, the BMW would be more reliable. We would probably pick the BMW, but that’s just us.

  11. Jon

    Hey,

    I have a e46 325cic, its been accelerating slowly and sounding like a bus at low speeds. My SES light is on and reads a p0599 t-stat heater control circuit high. Like i said, accelerating sucks, i try to do it moderately, but i end up being passed no matter how much throttle i give it. Its been like this all summer, but not one overheat ever. Heat will not work in the car, and some mechanics are telling me change the t-stat after i tell them about the p0599 code, but since its never over heated, and since its not a “t-stat stuck open” or “t-stat stuck closed” code idk if the t-stat is the proper diagnosis. Do you kno if its the t-stat or if its something else?

  12. aubrey

    my car started not idling straight even when driving it slow then after a distance it just switches itself off but after starting then it idles and revving straight again and back to norma.what can be causel

    • Adam Goral

      Definitely take this car to a local BMW specialist, you’ve got some sort of engine issue they will probably be able to diagnose quickly. DISA valve sounds like a probable cause, as well as bad ignition coils, bad spark plugs, or clogged fuel filter.

    • Adam Goral

      If you have fuel, and you have spark, you should next check for engine compression to make sure you don’t have some kind of major mechanical problem keeping the engine from running. Here’s a guide to compression testing an internal combustion engine.

  13. Karl Adamson

    Hi. I have a E46 preface,328 double vanos. I did the engine over and timing 100%. Car was driving well for about a year then all of a sudden started fluttering. I took off tappet cover and found the cams both at about 35° advanced while crank on tdc. I then replaced guides,tensioner and crank sprocket nd assembled all. Car drove well down the road then started fluttering again. I checked the cam timing again and again it was out. Please tell me what can cause this.

  14. Woody Brian

    I have a 2004 325ix wagon w/manual and 140k. I have a whine/howl in my rear end that increases with speed of the car, unrelated to acceleration or clutch engaged. At first, I thought it was noise from my winter tires but now back to summer tires and noise continues.

  15. Kindrick

    Hi I have a manual 2001 325xi with 162k miles on it. I am having a problem with a loud knocking that can only be heard inside the car and low to the ground. The noise isn’t coming from the transmission because at idle, in neutral, at a stand still it persists and goes away with higher RPMs. I recently replaced spark plugs, oil filter, oil, vanoss line, oil evap hoses, vacuum lines, and air filter. I am at a loss for what could possibly be causing the sound. Any help would be great!!

    • Adam Goral

      It can only be heard from inside the car? Are you sure the engine isn’t making this knocking sound, or perhaps some of the belt pulleys? Does the noise change with the speed of the interior blower fan motor?

  16. Phineas Nomatter

    Hi i have a318i 2002model E46 engine , the problem is it is consuming much of engine oil , no leak i m seeing , no sign at the xhuast

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