[DfVgyCjmFQnu]

I need to install my new tuning box, and want to remove the engine cover on my 335d. Exactly what tools do I need to do so? Thank you!

[EYE4SPEED]

There are 4 bolts that require an allen key (I forgot which size). Leave the one with on the driver side closest to the firewall out if you plan on swapping the box out (going to the dealer). You can also take off the tube thing that is on the firewall. I don't know what it is, but it pulls right off and has three attachment points. This thing gets in the way when you try to remove the cover.

[Ron1n]

Originally Posted by EYE4SPEED

There are 4 bolts that require an allen key (I forgot which size). Leave the one with on the driver side closest to the firewall out if you plan on swapping the box out (going to the dealer). You can also take off the tube thing that is on the firewall. I don't know what it is, but it pulls right off and has three attachment points. This thing gets in the way when you try to remove the cover.

The tubing by the windshield houses wires, but I don't recall what they're for. Leaving the one that's up in the driver's side corner makes getting under the cowl a PITA....just take it out if you want to get under the cowl, especially if this is the first time under there to install a tune. Yes, the ECU sits right up front, pretty much under the BMW emblem on top of the cowl, but it can still be a b*tch to maneuver under there.

[EYE4SPEED]

What I was saying is leave the bolt OUT after you remove it. While you could bend the cowl to get at the connection, I would not recommend it.

[Ron1n]

I just use a magnet to pull each one out after I've loosened them....haven't had an issue yet, and I've had a piggyback on my car for the better part of 2 years.

[DfVgyCjmFQnu]

Ok, I just needed a metric allen key. Also of note, one must remove the coolant refill cap prior to removing the engine cover.

[Ron1n]

Originally Posted by Ligament

Ok, I just needed a metric allen key. Also of note, one must remove the coolant refill cap prior to removing the engine cover.

Ummm...no you don't, but you do need to remove the oil cap.

[minus13]

You can take all bolts off and put them all back. Just get the right tools. Also, that black plastic piece that runs along the back of the firewall and obstructs your access to the back screws can be snapped right out with light pressure and then snapped back in when done. All the tools you need (assuming you have a 3/8" ratchet) are:

5mm 3/8"-drive 6" hex driver socket

and

Magnetic pick-up

There's no good reason to leave any bolts out.

[rogerdiaz]

Any areas of concern/parts that I have to cover/protect when detailing engine.

I want to degrease and power spray.

Have seen many threads but for gasoline engine bays, not specific for diesel engine bay.