has anyone taken out the firewall themselves to replace the heater hose? is it just also slide back in after putting back together?

removing the pre-firewall is the best way to work in engine rear

Few DIY'ers enjoy in doing the PCV/HPFP + Heater Elbow jobs.

I haven't had a reason yet to remove my pre-firewall. Likely around 110k.Mi or later due to my enhanced heat removal.

Heater core elbow was a royal pita to deal with, if I understand which hose. I dont think I removed the pre-firewall, but maybe I shifted part of it. job done about half a decade ago, not sure. I think i used the special clamp wrench to assist in removal/install of the elbow. Thick gloves and sleeves assist in limiting bandage use. glwr

I have - granted on the 5.5 not the 4.7 - BUT they are identical for this service. The key is getting out the "fake firewall" (easy) and the cover under the washer arms. There are threads...but, we could start anew - we have plenty of photos and tips. It really is not that bad of a job (make sure you have an electric soldering iron)......

Huh? Did you do yours on a hot engine after tossing in some razor blades?

The hose I worked on was in the firewall area, hard to reach, tight space, less than full leverage with tools. As you mention, the cowling should be removed, but this did not solve all the workspace and leverage challenges.

I have done it twice now, once on a 5.5 and once on a 4.7. The GLS was far harder than the E. Once I got the fake firewall out of the E it was far easier, sure it is tight but a 1/4" drive wrench can fit into the space. With a dental mirror (you know what I mean) you can get a visual on the bolts and go from there. The only thing that was really tight was the water temp sensor.

Now, if you do not take out the fake firewall - yes, tight at tight can be. At least on the E you can see it as compared to the GLS.

I saw a BMW service video by Nathan where half the engine is located under the cowel...

This can be intimidating until we have experienced with the countless steps.

• Wiper arms
• Cowel removal
• Pre-firewall
• Blind access
• Coolant bleed procedure

Hopefully the lubed O-rings did not roll over to leak pressure: repeat job ?

> PLANB :
Disable damages with unbelievable LOW HEAT...
I am driving with stock cooling setup and NO active fan.


My engine was producing extreme heat consistently since factory new.

Vibration-free engine now combines: powertrain RESPONSE + low HEAT + mpg EFFICIENCY from idle to 3k.Rpm.

No question raw power was always on tap, until recently low heat was unavailable.
Meaning the sizzling heat that ruins engine plastics is not GDI mandatory.

• Fan:ON in Winter
• Fan:OFF in Summer

> Win-Win...
I am running an experimental setup that has transformed M276stock heat intodriveability performance.

It's clearly the unsettled *TIMINGS* under 2000.Rpm that generate high heat + drop performance.

Predictable Bosch ECU timings become available with stable OIL pressure & stable DC power on stock firmware.