It's a simple job that should take 30mins to complete, and you will notice an instant performance increase and a reduction in fuel consumption.
So lets start off with a little about what the EGR valve does.
The EGR valve recirculates some of the exhaust gases back into the air intake and engine cylinders. It was designed to meet local emission laws by diluting the gases. (Nitrogen Oxide & Dioxide)
This is all very good when the vehicle is new, but over time the exhaust gases deposit oily gunk into the inlet hoses/intercooler/manifold and this reduces performance.
So how do we restore performance? It's simple, take off the whole EGR assembly and junk it. Add on a blanking plate to the exhaust manifold, and replace the intercooler hose and the engine can now breathe cold clean air again, and produce more power.
You may be wondering if EGR removal affects your car when it comes to MOT time. The simple answer is: no, it doesn't! (The MOT is a yearly test in the UK to check cars are roadworthy and comply with emissions)
The reason why EGR removal doesn't affect your MOT is because the MOT only checks for smoke particulates on diesels, not gas levels. Plenty of people have junked their EGR and have passed the MOT with flying colours!
Removal of the EGR can be undertaken using the most basic tools, so here's how to do it.
Removing the EGR valve from a 300Tdi Discovery
So before you can do anything, you will need to get is an EGR blanking kit. I got mine off Ebay for about £20, and the kit contained all the parts needed to complete the job: stainless steel blanking plate, gasket, screws and replacement intercooler hose.
Here's the kit I bought:
Take a look at the overview photo below. It shows the complete EGR assembly in situ. You can clearly see the vacuum operated valve assembly and the pipe leading to the air inlet pipe.
Here's a list of the tools you will need:
- WD40, Plus Gas or similar penetrating oil
- Coarse sand paper
- 6mm Allen Key
- Flat head screw driver
- EGR blanking kit with inlet hose
You will find the bolts are stiff to begin with, but once the rust seal has been broken they will undo fairly easily. We had to get a ring spanner on the end of the allen key to give greater leverage in order to break the rust seal.
Once the bolts are undone, you can pull off the vacuum tube that attaches to the EGR valve and place it to one side for the time being. We will deal with vacuum tube later.
2: Take a flat headed screw driver and remove the jubilee clamps from either end of the top inlet hose. Once undone, pull the hose away from the inlet manifold and intercooler. Once removed you will see just how badly the inlet manifold is gunked up!
The whole EGR assembly will now just lift up and out of the way and can be junked:
4: Clean as much of the oily goo out of the inlet manifold as you can. WD40 also acts a degreaser, so wet an old rag with it and wipe out as much as you can. It's a mucky job, but one worth doing while the inlet hose is off.
To do the job properly you would have to take the whole inlet manifold off, but this is beyond the scope of this article, so just be content with cleaning out as much as you can for now.
Fitting the EGR blanking kit to a 300Tdi Discovery
Once clean it will look like this.
4: Take the EGR blanking plate, gasket and bolts and attach to the exhaust manifold. Tighten the allen bolts.
5: Take the new inlet hose and attach it to the intercooler and inlet manifold. Tighten up the jubilee clamps with the flat headed screw driver.
The EGR vacuum is supplied by the same vacuum pump that powers the servo assistance on the brakes, therefore to be on the safe side, we need to block off this tube using a bolt.
Get a bolt that is bigger than the internal diameter of the tube and screw it into it. This will seal the vacuum tube. You can then cable tie it out of the way.
Now with the EGR outlet blanked off, and the inlet hose replaced the engine bay will now look like this. (The second photo is of the original EGR assembly in place so you can compare.)
All that remains to be done is start the engine and check for gas leaks around the blanking plate.
Take the car for a drive and you should now notice the engine now feels freer, with more power/torque at the bottom end. You should notice this when going up hills - hills which you took in 3rd gear before, you will now find you can take in 4th!
So for £20 and about 30 minutes work, you have a car which is breathing clean air again, producing more power and consuming less fuel!
Bloody great I'd say!!