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General E46 Forum
This is the place to get answers, opinions and everything you need related to your E46 (sedan, coupe, convertible and wagon) BMW!

View Poll Results: Have you experienced any of these issues, and if so, how many?
Lower Control Arms 26 56.52%
Vanos Seals 17 36.96%
Fuel Pump 16 34.78%
Oil Sensor 13 28.26%
Electric Windows 20 43.48%
Cooling System 29 63.04%
NONE! 3 6.52%
Multiple Choice Poll. Voters: 46. You may not vote on this poll

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Old 10-27-2015, 09:01 AM   #1
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Join Date: Nov 2012
Location: South Africa
Posts: 10
My Ride: 325i Stationwagon
Exclamation Common e46 issues & solutions!

Hey all
Thought I'd write a post outlining some of the more common issues with the e46's from my personal experience, if you have anything to add or any corrections, your feedback will be appreciated
Seeing as a lot of them are hitting 15 years old now, it's only fair to expect a few problems, especially with the electronics!

1. Lower Control Arms & Bushings
One of the more common issues for higher mileage cars. These usually go anywhere from after 80k miles / 130k km. The typical symptoms include hearing a rattling or clunking from the front of the steering when going over small bumps or gravel roads. Once it becomes slightly more serious, you will begin to notice play in the steering, and the car will feel like it has a mind of its own on uneven roads, and especially in windy conditions.
A nice way to test if your bushings are still good, is to jack ONE of the front wheels up, and feel if you can move it back & forth. The play is normally quite small (10 - 20mm) at the wheel, but has a huge effect on the steering.
The fix for this is fairly straightforward, although not the cheapest. Due to OEM lower control arms being notoriously problematic, the most popular replacement parts are manufactured by Meyle, and have a solid steel bushing (as opposed to the problematic rubber OEM one).
Approx. Cost (for both sides): $250 + labour

2. Vanos Seals
These are definitely one of the most common issues, especially for the double vanos models (320i, 325i, 330i). The symptoms are quite obvious, especially in the lower RPM range. Below about 3000RPM, the engine will have noticeably low torque, and uneven power delivery right through the RPM range, normally with a strong surge of power from about 3500RPM and up. This is normally accompanied with a slightly higher fuel consumption (but not too drastic), and sometimes with an inconsistent and rough idle.
The fix is not too easy unless you have a bit of a mechanical background. Replacement seals can be purchased online, and when replacing the vanos seals you'll need to take the valve cover off too, so it's best to replace this too while you're at it.
Approx Cost: $60-80

3. Fuel Pump
Perhaps a bit less common, but far more irritating and potentially worrying, are the fuel pump issues. Usually these don't go any time before about 125k miles / 200k km, but when it does you'll definitely know about it! If you're reading the codes being pushed out, lean codes are often a result of a fuel pump failing (but not always!). Running out of fuel when there's still fuel in the tank is another dead giveaway, and this is normally due to the fuel pump failing - you may see that you have about 1/4 tank left, but still run out. This is due to fuel being stuck in one side of the tank (not sure which) and not flowing across. The fuel pump sits under the rear seats, and a DIY replacement is not too tricky - I did mine a few years back.
A nice way to check the pump is to turn the key 2 clicks to the on position, without starting. You should hear a buzz for about 3-5 seconds - this is your fuel pump priming, it's completely normal. if you do NOT hear the buzz, try again and listen under the car. Still nothing? You probably have a problem.
Replacement pumps can be found everywhere online, and fitting them is normally achievable in a few hours, with a bit of patience.
Approx Cost: $150 - $200

4. Oil Sensor
This is a really simple issue, and generally is nothing to worry about. After starting the car, your oil light on the top of the cluster will light up (YELLOW), and will normally turn off after about 30 seconds. If this is the case, you have nothing to worry about.
If the yellow light stays lit, turn your car off and check your oil level. If your level is fine, then the sensor has most likely failed (not the end of the world).
If the light is RED, this is very rarely due to sensor failure, and it probably means you have an oil pressure problem (which we won't deal with here), have your engine checked if it recurs.
BMW have borrowed the same sensor they used in the E36, it's located at the bottom of the oil pan. Replacing it is also fairly simple, a replacement OEM sensor can be bought online or from a dealership (although more expensive), and it entails very little work (about an hour).
Approx Cost: $100 - 150

5. Electric Windows
Over time the electric window mechanism will inevitably fail after being used a bit, but it all depends on how often you use the windows. The track inside the pulley in which the cable runs, is made of plastic - so after a bit of weathering it's understandable that these may fail. As a result of this, the actual glass may be slightly loose and able to rock forwards/backwards. This puts a much greater load on the motors driving the window, which will lead to them burning out after extensive use.
Repairing the mechanism involves getting inside the door and taking panels off, but isn't too tedious. Repair kits can be found online fairly cheaply, by searching "Window Regulator Repair Kit" (Just make sure you're buying decent quality parts!).
Approx Cost: $10 - $25

6. Cooling System
Due to the fact that the cylinder head is aluminium, an overheat on these cars can be catastrophic. The entire head will twist, giving the same symptoms as a blown head gasket - so make sure to watch your temperature like a hawk!
There are a few parts that can fail in the system, all leading to different symptoms:
A thermostat failure may lead to the engine running at a lower temperature and possibly never even reaching normal operating temperature - this is fairly cheap to replace.
A water pump failure is somewhat more serious, but also fairly straight forward. A failed water pump normally leaks fluid (take note if you have to fill up with water regularly), and will also lead to the engine running at a HIGH temperature. You may also hear a whine from the engine bay - but this could be one of many things.
Expansion tank - These will generally fail after 90k miles / 145k km due to them being made of poor quality plastics, and fatiguing with temperature change.
In short, if you find yourself having to fill up your coolant on a regular basis, you should probably do a bit of troubleshooting before it leads to further problems. These parts are all known to fail, and it's far cheaper to replace the entire cooling system than it is to have a cylinder head redone.
Approx Cost:
Expansion Tank: $65
Water Pump: $50
Thermostat: $50

If anyone has anything to add, feel free to do so

Last edited by kashmir; 10-27-2015 at 09:48 AM.
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Old 10-27-2015, 09:09 AM   #2
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Join Date: Aug 2006
Location: RDU, NC
Posts: 3,968
My Ride: 03 330i
I had to vote none because I have never had any of these issues come up without addressing it before it became a problem.
I am jinxing myself but the oil sensor and the window regulators are all original and untouched. Fuel pump only recently changed for the first time, no sign of failure or soft failuer. 133k miles here.
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Old 10-27-2015, 11:29 AM   #3
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Join Date: Aug 2014
Location: Boston, MA
Posts: 45
My Ride: 2004 BMW 325xi
My issues have included 3 broken window regulators, a very disintegrated transfer case & bushing causing severe shaking upon acceleration, worn shifter linkage causing a lot of play in the shifter, and a repeatedly sliced ambient temperature sensor (until I found a better mounting spot for it.) Aside from those issues, I've done suspension and brake overhauls to fix leaking struts and broken springs (and obviously 4x4 ride height) and squeaky, shaky, non-functional brakes. I'm at 120k, and loving my E46 more and more every day
2004 BMW 325xi 5MT | Bilstein shocks/struts | H&R Sport Springs | Morimoto Mini D2S bi-xenon retrofit | E60 shift lever w/ ZHP knob | OEM Style 67 18s refinished in Porsche Ice Silver Metallic | Lamborghini green interior trim/calipers/lug covers (+250hp) | various maintenance overhauls | etc. things I broke and am too lazy to fix at the moment | stockpile of parts for built engine swap… |

2010 Mercedes C300 Sport 4MATIC | stock af |
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Old 10-27-2015, 12:11 PM   #4
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Join Date: Aug 2015
Location: Overland Park, KS
Posts: 379
My Ride: 2002 325xi
It is my understanding that for number 5 the regulator breaking is a more common issue than motor burning out. The cheapest price for a regulator is $42. I still voted for #5 in the poll.
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Old 10-27-2015, 12:14 PM   #5
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Join Date: Nov 2012
Location: South Africa
Posts: 10
My Ride: 325i Stationwagon
Originally Posted by veektor View Post
It is my understanding that for number 5 the regulator breaking is a more common issue than motor burning out. The cheapest price for a regulator is $42. I still voted for #5 in the poll.
from my logic, broken regulator leads to overstressed motor, leads to burnt out motor.
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Old 10-27-2015, 12:21 PM   #6
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Join Date: Oct 2015
Location: St.Louis
Posts: 6
My Ride: 2000 323i
I have had to replace the expansion tank, radiator, and various cooling system hoses. the car was involved in a front on collision before I bought it, which could explain the radiator. and i know the water pump was replaced by the previous owner.

My rear passenger window regulator did need to be replaced.

And from your description it sounds like my control arms may need to be replaced. I am getting a death wobble at high speeds on the highway when I make slight turns, such as changing lanes or highway interchanges. It could also be worn tires/low pressure or a bad wheel bearing (I haven't had a chance to dig in and figure it out).
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Old 02-23-2017, 06:29 AM   #7
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Join Date: Feb 2017
Location: Sydney
Posts: 1
My Ride: BMW E46 318i 2004
My 318i 04 overheats at idle and goes to normal when driven and has a whining noise in the engine bay which gets louder as the RPM's increase

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