Do It Yourself - Replace your 6 Cylinder BMW Exhaust Manifolds / Cats - Wrap Up - Part 4 (BMW E46 320i)

Welcome back to my shop diary on my '99 BMW E46 320i and the wrap up to the most dreaded repair on this engine in this chassis which is the complete replacement of the exhaust manifolds with built in catalytic converters which are these babies here:

After having reinstalled the complete rear exhaust system and center structural support beams:

As well as all the underbody covers and beams which I wrapped up at 8:15pm after 12 hours and 15 minutes of marathon shop work I returned the next day to get the car and put finishing touches on it:

An initial visual inspection of the new manifolds:

And a second start up and walk around:

A world of difference! To recap here is what was replaced in the session:

• 2 new exhaust manifolds with cats bank 1 and bank 2
• 2 new post cat lambda nodes
• new gaskets and bolts/nuts connecting the manifolds with the rear exhaust
• 4 new studs put into the cylinder head and 16x new nuts for the manifolds
• 2 new exhaust manifold gaskets/heat shields

I also deleted all the codes relating to the issues and they didn't return since mainly the error code relating to lambda node 2 post cat reporting wrong values or nothing at all.

Now here's what's still to be done to finish it:

• reinstall AC line and fill the AC system
• reinstall various covers and plugs to the engine
• reinstall washer bottle
• reroute and connect the post-cat lambda node cables

Manifold Replacement Wrap Up

First up the cabin air filter housing has to go again:

Remove the topside engine cover and then route the lambda cables like this:

Make sure they're in the right order!

Here is how I tied them behind the engine:

And up close on top of the fuel rail:

Put everything back together and the AC line back in:

After an initial test drive I checked the gasket and nuts for good fit and tight sealing:

Looking good!

I had the AC refilled and it works like a charm.

I put the engine cover bolt plugs and washer bottle back in and gave everything a very thorough cleaning:

Following this I recommend a good, long, hard test drive:

I got it up to around 210km/h which was a good 200km/h GPS - not bad for a 400.000km+ engine that's never been opened!

None of the error codes have returned and the engine, more specifically the exhaust, sound like new.

To top it all of I replaced the engine top cover which was pretty destroyed after 20 years to give it a nice fresh look:

Thanks for following me on my final steps in getting my daily driver to its well deserved retirement (at least from daily driving duties :)

Steem on fellas!