So after a brief bright spell on Saturday I decided to clean out the intake manifold as it was pretty caked with crud. It took me just over an hour and a half to remove the manifold, another hour to clean it and then around 45mins to put back on as I now knew where everything went.
This is the manifold removed:
Now I'm not a physicist or engineer by any means, but I found that when jest-washing inside the manifold the branch on the far right was pi55 poor at getting any water flowing through it, it seems like a pretty poor design but I suppose under high boost it must work ok
This was the inside before cleaning, having done 81k miles:
I gave it a scrape as far as a long screwdriver would let me, knocked the crud out that I'd loosened, jet blasted it a bit and then gave it 4 rounds of foam de-greaser and Mr Muscle oven cleaner (the de-greaser kept clogging). After an hour's work and some time to dry it looked a little more like this:
Much wider inlet and smoother airflow, I have noticed that the power is smoother, more consistent and doesn't feel so choked or wheezy near the top end (3.5k+). Definitely worth doing and not that difficult, even for a non-mechanic like me!
The space is tight so not really suitable if you have hands bigger than a baby's or wrists wider than a toilet roll tube! This is the space where the manifold comes out from:
I followed this
guide HERE as recommended by Muttley, but I would make a few points:
1. The TIP doesn't "need" to be removed, you can work around it and move it out of your way to a certain extent and still access everything.
2. I would remove the TIP, it's a pain in the deriere working around it!
3. The EGR cooler doesn't need to be removed either - simply push it back and let it rest on the exhaust manifold as above, the coolant pipes then don't need clamping and it saves some time.
4. Remember to re-fit the gaskets from the EGR cooler to the EGR!!! I forgot one and ended up hitting limp mode the next day while I was 40 miles from home on a day out with my girlfriend! Needless to say it was pretty annoying/worrying. It had started raining when I was refitting stuff so I was in a rush to refit everything
Apart from that it's a simple if time consuming job and it's and it's working well now, except for the boost gauge rattle that has come as a result
Got to get my n/s CV boot changed soon, try and sort out the clunk coming from my driver's side suspension and squeaks coming from the rear, and then look at getting a catch can fitted to clean up the air flow completely.
As always, comments welcome