Can you clean EGR without removing? Spray vs. manual test

[saskak]

I have been always cleaning the EGR valve in my 1.6HDi M59; 2007 manually every ~2-3 years, depending on the number of miles driven for peace of mind.
There is quite a number of videos of people using some sort of an EGR cleaner spray that you spray in the air intake (past air filter, pre-turbo) and claim that these clean the EGR.

So, I decided to test it for myself and see what the outcome is and how clean the EGR is after these sprays. I dismantled the EGR and had a look how dirty it is. It was not too badly clogged, just fine carbon powder everywhere. I then used the Wynn's diesel EGR cleaner spray and followed the instructions, i.e. under idle spray max 1s intervals (whole bottle) and then take it for a spin without exceeding 3,000rpm. I then again removed the EGR valve and I could not see any difference whatsoever. The exact same carbon powder everywhere. So, I cleaned it manually with a toothbrush and dishwashing liquid for ~10min. It was nearly spotless after that. See the photos.

I also made a video of the whole test if you want to see it: https://www.youtube.com/watch?v=koSxf67CtHI
There are more photos and comparisons side-by-side in the video.

So, to answer my own question in the title. No, you cannot clean the EGR valve using a spray in the air intake manifold, or at least the spray that I used. Maybe others could be more successful, but I doubt it. My EGR valve was not really badly clogged, I had cleaned it ~2 years ago and due to covid I think I travelled ~10,000 miles only. Maybe if the EGR is really clogged, one of these sprays may do a better job.

Here is a photo Before the spray and after:
   

Here is a photo Before the spray vs. the manual toothbrush and dishwashing liquid:
   

[cancunia]

Thanks for the post saskak. I'm hoping I won't need to clean the EGR on my 1.6HDi but at least I have some good info on how to do it if needed.

[geoff]

Given how quick and easy it is to remove and clean the EGR then removal is surely the way to go !

Added bonus is with " hands on " you get to find other things and sort them as well.

My own EGR removal for cleaning found, apart from a sticky actuator, that the connection to the EGR Cooler had fractured which allowed fumes out and caused lumpy running.

Use of a spray cleaner ( whether effective or otherwise ) would never have found that ^^^.

[saskak]

Given how quick and easy it is to remove and clean the EGR then removal is surely the way to go !

Added bonus is with " hands on " you get to find other things and sort them as well.

My own EGR removal for cleaning found, apart from a sticky actuator, that the connection to the EGR Cooler had fractured which allowed fumes out and caused lumpy running.

Use of a spray cleaner ( whether effective or otherwise ) would never have found that ^^^.

Haha, so true. First time I dismantled it, noticed that the air box was rubbing on the top part of the EGR and had made a hole there. The electronic (top part) was pretty much knackered with bits floating inside, maybe that's why it was not working in the first place. No amount of spray would have brought it to life.

[notsofast]

I've read somewhere that oil catch cans (which you mention on your video) are illegal in some jurisdictions, and a reason for failing an emissions test, and I'm wondering why this is, seeing as the oil vapours that they catch are, well, caught, and not released into the atmosphere?

[saskak]

I've read somewhere that oil catch cans (which you mention on your video) are illegal in some jurisdictions, and a reason for failing an emissions test, and I'm wondering why this is, seeing as the oil vapours that they catch are, well, caught, and not released into the atmosphere?

Well, I always remove the oil catch can before annual testing (MOT in the UK). Overall the OCC will reduce emissions due to capturing some oil that will not get burnt when it is closed syetem as in mine and not venting to the atmosphere. Nevertheless, it is viewed as emissions modification and they might fail it for that.