recently a friends Mazda 6 ts 2.0 diesel 2005 has started reporting a low boost condition fault. I have identified the issue as being the egr stuck open during boost as the issue. I removed some of the piping to the EGR and left it to soak in carb cleaner which has removed some of the crud. However the build up is quite bad. The pipe is metal and about 20mm in diameter but is about 3/4s restricted by crud. I haven't yet removed the EGR itself or the intake manifold but i'm betting its just as bad. Any ideas short of throwing the lot away?

  • google "gun cleaning brush" and see if any of those look like they might work. If you need more power, get a flexible cordless drill extension and a small wire brush attachment. I know that's not the stackexchange way, but...
    – coburne
    Sep 21 '16 at 14:16

Although I've never done this, a trick I've come across involves feeding motorcycle clutch cable with copious amounts of brake cleaner into the blockage, attaching the end of the cable to a cordless drill and effectively drill out the carbon.

  • @coburne sure, feel free to add an answer with pictures and descriptions. It may not work for all blockages but it helps to have alternative options when dealing with something like this :)
    – Zaid
    Sep 21 '16 at 14:15
  • I didn't have a good answer, but I added a comment, because I'm not sure that fits his needs or not. I'm just spitballing.
    – coburne
    Sep 21 '16 at 14:17
  • Thanks for the idea. I'm thinking of some kind of hybrid between your answers. The caustic soda and crud would be ok going though the engine I would have thought. Just get it nice and hot before I start :)
    – Mark
    Sep 21 '16 at 14:26
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    @Mark well I would avoid having the engine ingest crud and chemicals if I can help it. You don't want "stuff" in the cylinders for obvious reasons :) Both brake cleaner and carb cleaner are volatile and won't cause such issues
    – Zaid
    Sep 21 '16 at 14:44
  • most of the crud should be able to be removed with a vac or air compressor. I'm thinking of the small amount left over. i'm thinking screwfix.com/p/laser-wire-brush-20-piece-set/16669?kpid=16669 screwfix.com/p/titan-flexi-bit-holder-300mm-x-hex-shank/…
    – Mark
    Sep 21 '16 at 14:45

There are a number of ways to clean it but I've had personal success with oven cleaner and a tooth brush. Obviously wear protective gloves and do it somewhere well ventilated. Also, throw the tooth brush away when finished.

Good luck.

  • Do you mean oven cleaner/ hydrochloric acid? The issue is the pipe is ridged and quite long I wont be able to manually scrape/scrub the entire thing
    – Mark
    Sep 21 '16 at 10:23
  • Mr. Muscle was what I used. I think it's caustic soda based maybe? Not sure but it worked well. Perhaps the pipe could be removed from the vehicle, cleaned from both ends and subjected to a soak in something? Other thing I could suggest would be bottle brushes, the types used to clean babies bottle out with? Sep 21 '16 at 11:48

In order to clean it, just remove it

This is a messy job.

You don't want any of that carbonized waste going into the motor or all over yourself.

If you get an automotive parts dip, you can remove the EGR and place it in a basket and let it soak.

I use this for carburetors to EGR's. It will eat aluminum if you leave it in too long so check it periodically while it's soaking.

This is the cleanest and quickest method you can do. Before you put in the basket, if you must, you can pick away at the big chunks with an oil pick to help get it started. You will find quickly that this is an extremely messy job and you may want to forgo the manual picking and just allow it to soak in the parts dip.

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