e46 M3 maintenance/lockdown thread

[Obioban]

The e46 M3 has two significant failure modes, that can cause you a LARGE expense if you wait for them to fail instead of addressing them preemptively. I would very much suggest locking down the VANOS bolts/tabs and the subframe BEFORE you have failure-- see post 4.

This thread will be broken down into 3 sections
1. When to do what to maximize component life
2. When to replace what to keep the car as reliable as new
3. When to do what to keep the car driving like new
4. Permanent fixes for e46 M3 catastrophic failure modes that everyone should do BEFORE they have an issue.
5. Permanent fixes for e46 M3 common failure areas


Attached to this post is the official BMW inspection check form for the e46 M3. If you want to check all of the areas of the car the BMW things will wear out, this is your document.

Service_Checklist_2004_US.pdf-link.pdf

You may notice I don't have the clutch anywhere on here. That's because it lasts pretty much forever, driven competently. If it starts to slip when you floor it at low RPM in high gear, that's the time when you should replace it. Note: Once if slips in that condition, you should replace it ASAP so as to not score the flywheel (so you can reuse it).

[Obioban]

1. When to do what to maximize component life

The e46 M3's OBC (on board computer) has a service interval calculator. This calculator is based solely on gallons of gas consumed. This system works remarkably well, as the harder your drive, the more frequently the car should be serviced. This means the service intervals below apply equally well to track cars as they do to highway cruisers.

The OBC service interval counter alternates, each time it is reset, between "Oil Service" and "Inspection". BMW, in the wisdom of "free service" from the dealership decided that oil changes were only needed every 15,500 miles (+- driving style, as it's adjusted for fuel consumed). Pretty much nobody things this is a good idea (including BMW, prior to the era of "free maintenance").

That said, we can still make use of the OBC service calculator. By doing oil changes when the OBC service interval calculator says 7750 miles or 0 miles, and doing diff/trans fluid changes every inspection interval, you get very reasonable fluid change intervals, tailored to your specific style of driving.

When the OBC reads 0 (or close to it), after performing the relevant service you should reset the system.

OBC service internval reset procedure:

1. Turn the ignition key in the "off" position.
2. Press and hold the lower left button on the instrument cluster, which is the trip odometer button.
3. While the trip odometer button is pressed, turn the ignition key to the FIRST position (KLR).
   1. IMPORTANT: DO NOT GO TO THE SECOND POSITION, if you do, remove the key and start over
4. Keep the trip odometer button pressed for approximately 5 seconds until one of the following words appear in the display: "OIL SERVICE" or "INSPECTION" with "rESET" illuminated above.
5. Release the trip odometer button and press and hold it until "rESET" flashes.
6. While the display is flashing, press the left button briefly to reset the service interval.
7. After the display has shown the new interval, the following will appear: "END SIA".

The system can only be reset again after 2.5 gallons (10 liters) of fuel have been consumed.


So, what should you do when? I would suggest the following:

Every 7750 OBC "miles":
-Oil change (including filter)
n.b.: oil changes should be done yearly, even if you don't make it to the OBC mileage target. Combustion byproducts get in the oil that degrade it with time, in addition to the degradation of use.

Every OBC Inspection Interval (so every other OBC service interval reset):
-valve adjustment (Note: if you use the OE BMW valve cover gasket, it's good for ~100,000 miles of use before it starts to leak)
-Trans fluid (spec is 75w80, GL4)
-Diff fluid (spec is 75w-140-- use the OE BMW fluid with FM booster if you don't want your diff to be noisy)
-cabin air filter
-engine air filter
-fuel filter
-power steering fluid (ATF)

Every other OBC inspection interval:
-Coolant (BMW coolant mixed 50:50 with distilled water)
-spark plugs
-belts

Every ~100,000 miles:
-SMG hydraulic fluid (CHF-11S)
-replace MAF (needs to be far more frequent if you're using an oiled filter and/or MAF cleaner)

Every other year:
Brake fluid (note: track cars should do this yearly, before the track season)

[Obioban]

2. When to replace what to keep the car as reliable as new

Most components have a reasonably predictable service life. Generally it's cheaper to replace parts before they fail, as it avoid tow trucks and any sorts of cascading failures. With that said, here are when I would replace what, as long as some good "while you're in there" suggestions:

There are a number of items that would be on this list, were there not permanent fixes for them (see post 6 in this thread). If you don't want to use aftermarket fixes, consider most of them ~100,000 mile service life components.

50,000 mile intervals:
RTABs (technically should be below, but these can be pretty ruinous)

100,000 mile intervals:
-entire cooling system (radiator, thermostat, water pump, hoses, coolant temp sensor)
-belt tensioners and idlers
-Guibo
-CSB (driveshaft center support bearing)
-fuel pump (replace fuel filter at the same time)
-replace or rebuilt fuel injectors, replace seals
-pre cat 02 sensors
-valve cover gasket (would suggest timing this to coincide with a valve adjustment)
-rod bearings (Note: I would actually base when to do these on oil analysis (specifically lead and copper content in the oil), but if you're not doing oil analysis they should be a 100,000 mile interval item. Stock bolts are better than ARP's (more clamping force, rounder bore).
-coil packs (suggest keeping the originals as spares and keeping one in the trunk, as these are common failure items)

When the trans is out:
-Pilot bearing
-pivot pin
-throw out bearing
-read main seal
-all exhaust gaskets and nuts for sections that were removed for the job.
Note: flywheel can be reused for at least 2 clutches, if not scored)

When the rear subframe is out:
-subframe bushings
-diff bushings

When doing rod bearings:
-engine mounts
-oil pan gasket

[Obioban]

3. When to do what to keep the car driving like new

Suspension components wear out. The more precise the car, the more noticeable this is... so it's super noticeable on the e46 M3. One of the best upgrades you can do to a tired car is new stock bushings.

The intervals below are for stock components. Aftermarket can have a shorter or longer lifespan, depending on the part)

50,000 mile intervals:
-RTABs (suggest either stock or sealed monoball)
-FCABs (suggest either stock or sealed monoball)
-Trans mounts (note: stiffer than stock trans mounts can be a significant source of NHV)
-Shocks

100,000 mile intervals:
-Engine mounts (note: stiffer than stock engine mounts can be a significant source of NHV)
-diff mounts (note: replacing diff mounts with new stock requires replacing the rear cover. Stiffer than stock diff mounts can be a significant source of NHV with little to no performance benefit)
-front control arms (arms must be replaced to replace integrated monoballs)
-rear outer upper and lower control arm monoballs
-rear inner upper and lower control arm bushings
-sway bar end links (note: these will wear out far faster if you have significant sway bar preload)
-sway bar bushings
-rear shock mounts (RSMs)
-vanos seals (beisan)

150,000 mile intervals:
-subframe bushings

[Obioban]

4. Permanent fixes for e46 M3 catastrophic failure modes that everyone should do BEFORE they have an issue.
The following should just be considered part of the purchase price of an e46 M3. If you have purchased a car where you don't have PROOF that they were done (not just the owner saying it), you should be doing these before driving the car.


Subframe fixes:
There are two ways to address the subframe issue-- one cheap, easy, and likely good enough for most use cases. The other will absolutely lock it down, regardless of how you use the car.

1) cheap/easy way: inject structural foam (from BMW) into the subframe cavity. The is the official BMW fix for the subframe issue. Foam costs ~$100, and the job takes ~30 minutes to do. To date, I have not see anyone have subframe failure so long as they did this BEFORE cracks developed at the subframe mount points. BMW part number 83190007361. I suggest doing both the driver and passenger side cavity, which requires two foam kits.

2) A solution that properly distributes the torque load of the subframe into the chassis, e.g. the Vincebar. These kits address the fundamental engineering issue that causes the rear floor issue in first place. Parts aren't hugely expensive, but the install is a fairly involved job-- beyond the scope of many weekend warriors.


VANOS fixes to prevent catastrophic failure that can take out your engine
There are two ways the VANOS system can cause you large expense-- the vanos oil pump drive tabs sheering off and the cam bolts backing out. Happily these two items can be fixed for $150 (post core return) if you DIY the fix before they fail.

1) The Beisan systems VANOS oil pump disk uses smaller tab holes than stock. This decreased slop cause the splined hubs tabs not to sheer off

2) Assuming your cam bolts are in good condition, cleaning them, applying oil resistant loctite blue, and torquing them to spec will prevent them from backing out. People often "upgrade" the bolts by swapping them out for a higher grade. There is no harm to this, and it will allow you to torque them to a higher value. But, it's also unnecessary-- stock bolts, with loctite, torqued to spec is a sufficient fix. That said, stock bolts are easy to over tighten and grade 12.9 Bolts can be had for a similar price as new stock from Lang racing (which are harder to strip by over torquing).

While you're in the VANOS system for the above, doing some of the VANOS jobs in the next post (as well as the seals) adds almost no labor and ensures trouble free VANOS operation going forward.

[Obioban]

5. Permanent fixes for e46 M3 common failure areas

High Temp CPV (constant pressure valve) O-ring
Issue: The stock O-ring on the CPV doesn't hold up to the heat of the headers. This causes it to fail, resulting in an oil leak under the headers.
Fix: High temp Vitron O-ring
Cost: $5
DIY Difficulty: 2 with headers off, 6 with headers on

VANOS solenoid pack (beisan)
Issue: Solder joints in the solenoid pack bread down over time, causing the unit to fail
Fix: Beisan reflows the solder and encases it in epoxy, making it so the issue can't occur again
Cost: $150 post core
DIY Difficulty: 3

Timing chain tensioner guide (beisan)
Issue: Stock timing chain tensioner guide wears down over time
Fix: Beisan makes a thicker guide from a more durable material
Cost: $80
DIY Difficulty: 6

VANOS rattle (beisan)
Issue: VANOS splined shafts can develop rattle
Fix: slop removed, rattle removed
Cost: $80
DIY Difficulty: 3 (once you're already in there)

VANOS high pressure oil line (updated OE part)
Issue: The vanos high pressure oil line flexes, eventually resulting in failure
Fix: BMW updated the part (11367837614) to include an extra mount point, eliminating the flex
Cost: $100
DIY Difficulty: 3

Diff mount bolts
Issue: Original bolts were partially threaded, and could loosen and/or sheer
Fix: BMW updated the bolts (23001222891)to be partially threaded. Combine these with loctite and the proper torque, and they won't.
Cost: $10
DIY Difficulty: 2

Secondary air pump fails/leaks
Issue: secondary air pump is acting up
Fix: Block it off using BMW PN 11121438086 (with new gasket and nuts), and code it off using the MSS5X binary modification tool
Cost: $30
DIY Difficulty: 3



Optionally necessary, depending on mods done to the car.

If you run aftermarket camber plates that don't distribute the load into the shock tower well:
Front shock tower reinforcement plate
Problem: Some camber plates do not distribute the load of the shock evenly across the shock tower, which over time can lead to the shock tower cracking.
Fix: OEM BMW shock tower reinforcement plates. These come from BMW Africa, where they put them on cars that have to frequently drive on unpaved roads. http://www.turnermotorsport.com/p-32...ates-pair.aspx
Price: $23
DIY difficulty: 2

If you run aftermarket rear ride height adjustors that don't distribute the load well:
Rear control arm reinforcement plate
Problem: the ride height adjustor focuses the weight of the car on a smaller area than the stock spring does
Fix: Rear spring perch reinforcement plate http://www.rogueengineering.com/mm5/...Category_Code=
Price: $55
DIY difficulty: 2

[Obioban]

reserved...

[Bostonbruck]

Thanks for the thread. Lots of great info on here

[r4dr]

Diff mount bolts
Issue: Original bolts were partially threaded, and could loosen and/or sheer
Fix: BMW updated the bolts (23001222891)to be partially threaded. Combine these with loctite and the proper torque, and they won't.
Cost: $10
DIY Difficulty: 2

I'm assuming red Loctite, and according to TIS the torque spec is 20 nm (14-15 lb-ft) + 90*. Just wanted to add this in case someone was looking – I found a YouTube mechanic suggesting 61 lb-ft which is... not ideal. My interpretation of the TIS is that you hand tighten while the diff is supported, remove the support, then torque to spec.

Sources:

Install info at the bottom: https://www.newtis.info/tisv2/a/en/e...ntings/BMBGkMY
Torques under 1AZ: https://www.newtis.info/tisv2/a/en/e...ntings/5XGnMyr

[MFANTIK]

Do we have the details from the thread that has all the OEM for the replacement and maintenance parts?

http://www.m3forum.net/m3forum/showthread.php?t=190111

[Obioban]

Do we have the details from the thread that has all the OEM for the replacement and maintenance parts?

http://www.m3forum.net/m3forum/showthread.php?t=190111

FCP has that for any part number you search for. "genuine" = BMW branded, "OE" = company that made it for BMW, "OEM" for a company that makes other parts for BMW but not that particular one. They're right 99% of the time. You can generally verify by comparing pictures of the BMW part to the alternate suppliers.

[duracellttu]

What is, if any, the maintenance interval associated with the rear axles? Do the CV joints wear? What needs to be replaced?

ill have them removed while doing the rear wheel bearing job. Hoping to address any items during that time.

[Andy2424]

A question, which brake fluid do you use with steel flex hoses

[mrgizmo04]

A question, which brake fluid do you use with steel flex hoses

Same as with non steel

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[Inizes]

Do we have a guideline on the mileage for a fan clutch replacement? I’m thinking of doing it since I’m at ~100k. Don’t think it’s loose or going, but I would rather not find out by it exploding and my hood getting damaged.