e46 M3 maintenance/lockdown thread

[r4dr]

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.

I believe you can feel play in it, can't you?

Either way, if you're doing a cooling system refresh at 100k you're taking the fan clutch off anyway, might as well replace it. I know at 60k when I was doing my VANOS fixes, the clutch was pretty grimy with dirt and gunk. I can't imagine that's good for it.

[Obioban]

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.

100,000 is when I do it.

[RevUpp]

That's a great writeup @obioban!

About the Diff bolts info, there's a small misunderstanding at the explanation. First gen diff bolts were fully threaded, the upgraded now are partially threaded. (the text says the same about old/news, I'm assuming it's a writing mistake).

Supposedly the full bolt threading was the culprit of broken bolts for what I heard/read...

By the way, I don't know in your country, but here in Spain now, if you want to buy them at the stealership (23001222891) they ask you to buy a pack of 10, when in the past I bought them separately for my ex E46 M3... So that was like near 50+ euro lol

Anyway, you can buy them at any specialized store for cheap, just taking with you the bolt measurements, which appear at the realoem. Bought a pair for 0.18 euro, only difference was the head, mine now are hex.
Added two washers.

M12 x 50, structural resistance 8.8 (realoem)

(DIN-6921 8.8 for a local search) you can select the finish, black, chrome, zinc-ed or not, the threading distance measurements, etc...

[cobra]

What's the latest on subframe reinforcement? It sounds like foam is NLA and also not really recommended because it hinders the welding repairs.

My subframe is perfectly fine on my 05 and I don't thrash on it too badly. Wondering if it's worth doing anything.

[Singh]

This is very informative, thank you.

[Obioban]

What's the latest on subframe reinforcement? It sounds like foam is NLA and also not really recommended because it hinders the welding repairs.

My subframe is perfectly fine on my 05 and I don't thrash on it too badly. Wondering if it's worth doing anything.

If you're going to have the car for any length of time, it's worth doing.

Foam is not NLA.

Best lockdown out there is the vincebar, IMO.

[cobra]

If you're going to have the car for any length of time, it's worth doing.

Foam is not NLA.

Best lockdown out there is the vincebar, IMO.

It hurts me to think about cutting up a perfectly good trunk floor to install the vince bar.

Is there really any downside to doing the foam, or could it be chipped away and repaired properly if it did end up cracking?

[Thoglan]

It hurts me to think about cutting up a perfectly good trunk floor to install the vince bar.

Is there really any downside to doing the foam, or could it be chipped away and repaired properly if it did end up cracking?

Unfortunately foam is not recommended imo. Should you develop cracking after the foam is installed you might have trouble finding and installer who wants to weld up those cracks and fix the issue properly. The foam is prone to catching fire and makes welding miserable not to mention a lot more toxic fumes.

I can understand the apprehension of not wanting to cut into the boot floor if it's not cracked. I was in a similar position, my bootfloor was undamaged however I did have popped spot welds on the wheel arch. Just finished the install of the cmp full top mount kit last week, gotta say it looks pretty 'clubsport' esque once painted and with carpet cut around it. But vince is a good 'invisible' option.

[heinzboehmer]

Any guidance on when to replace the engine sensors (camshaft position, crank position, knock, etc.)? TPS is going, so I figured it might be worth replacing everything else right now too.

[OEM3]

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

What are the symptoms of worn:
1) Transmission Mounts
2) Struts/Shocks
?

I ask because my car is now at 75k miles and these are still original. Want to know if I would see much benefit replacing them. Much of the mileage has been on smooth, boring highways so perhaps they've seen less wear than average? 😇

I try to follow this (extremely informative) thread to a T so I'm tempted to do both of these now; don't want to fix what ain't broke though...

[Hammerfang]

Super helpful, going to use this as a guide for maintaining my M3.