750iL M73N secondary air non-return valve removal assistance

[TheAngryBear]

2003 750iL
VIN: DD74441
Issue: Secondary Air System Codes with SES light
Sources checked: meeknet, e38.org, search here and other channel, google search, newtis (https://www.newtis.info/tisv2/a/en/e...system/AJ9z2bA and https://www.newtis.info/tisv2/a/en/e...system/AM8KOpB)
Attempting to remove and clean the non-return valves to determine if that is the issue.
I am following the newtis to remove but having trouble accessing the two rear nuts.
Looks impossible... but there is probably a good trick someone has to access the circled nuts to remove the valves.
Is it just an extension from the air box area?
Angled box or open wrench?
I am just not seeing it.





2001 750iL DD74441
Stock

RIP: 2003 540iA Sport GS56111
H&R front springs, Ultimate Cup Holder, Euro Dash & Armrest, Grom, BavSound Stage1

[CPHES]

I think with a 10mm. I had to get mine out when doing the water pump. What codes are you seeing? I have a 2000 / DD73956

[TheAngryBear]

Using DIS44 I have “Implausible signal” P0410.
It is my only active code but causing the SES light.
It may not be the valves but given the level of grime on the engine I imagine they could use a good cleaning. And if that can resolve then all the better.

Editing system is good to go (touch wood) for the next 50k given prior service. If needed I will pull the coolant hoses for a drain and refill but would prefer to leave the pump etc in situ.


2001 750iL DD74441
Stock

RIP: 2003 540iA Sport GS56111
H&R front springs, Ultimate Cup Holder, Euro Dash & Armrest, Grom, BavSound Stage1

[CPHES]

I’ll look at my guy in the am, but that drip tray in front of the oil fill might have to come off. I think I just followed that TIS you linked

[TheAngryBear]

The drip tray is easy, it just pulls off.
Accessing that rear bolt is the tricky part.
I guess if we figure it out without removing other items beyond TIS it is writeup time.
Thanks for the assist!


2001 750iL DD74441
Stock

RIP: 2003 540iA Sport GS56111
H&R front springs, Ultimate Cup Holder, Euro Dash & Armrest, Grom, BavSound Stage1

[CPHES]

Yes, the drip tray is easy. I looked today, but I did this job years ago. I think the hose clamps have to come off, and the assembly with all tubes came off. Remember, I was getting down to the pump. If it was in the way, I removed it. I will write back, if I remember more.

[TheAngryBear]

For the record, I figured out how to do it without draining the coolant. It is a pain but doable. Just a few extensions.
Here is my rig next to the air filter for size reference. (Note the filter “catching” the blowback from the exhaust.)

As it has to be fed and routed the multiple extensions are actually preferred as getting the complete assembly to it is not possible. Also this is 1/4” drive, anything larger is to broad to fit.
Here is the entry point

And it in the nut.


All in all, I say drain the coolant for the room to work and direct access. For just that reason I am not touching it for now (as I need a new air pump regardless) and figure if I can do a coolant swap at the same time it will be just as easy. And likely I will do it at the auto hobby for the lift and ease of disposal.


2001 750iL DD74441
Stock

RIP: 2003 540iA Sport GS56111
H&R front springs, Ultimate Cup Holder, Euro Dash & Armrest, Grom, BavSound Stage1

[CPHES]

Yeah - sorry, in my case I was doing the H2O pump, so the coolant was drained.