General Information regarding EGR related problems and solutions.

[skyship007]

Originally Posted by amclellan

My Volvo V40 1.9 Diesel 115 bhp, is drinking more fuel, accelerating less well and the engine is hesitating at around 2000 rpm. The car has a full service history, so what is the problem? Then I noticed this thing called an EGR valve, which Volvo neither service nor check.
Inspired by this excellent thread by Biotoxic I thought I would clean my EGR valve. All went well. The solenoid separated from the EGR valve. But the EGR valve was stuck fast in the inlet manifold.
So, lots of penetrating fluid, a wooden stick and a rubber hammer were tried, with no reward.
Then a cold chisel and steel hammer was tried. The EGR valve was bruised but survived unmoved.
I realised that less brute force and more brain power was necessary. I researched the idea of heating the manifold and made a bespoke tool to use as a drift.
I know nothing about the manifold's aluminium alloy, but realised that an oxyacetylene torch would not be good. I settled for a hot air gun (1800 Watt, 600 Centigrade).
My new tool was made from an old tyre lever and a M8 nut and bolt.
An appropriate weight hammer was selected
I applied the hot air to the manifold casting in the area of the EGR valve. After about 10 minutes the EGR area of the casting had reached 50 Centigrade. Then the new tool was engaged in the bolt holes of the EGR valve. A few light strikes with the hammer caused the first movement of the EGR valve. 10 minutes later it was out.
It was oily, sooty and black. I tried to clean it with kerosene, acetone, carburetor cleaner and a toothbrush. None were that helpful. More reading suggested that a ultrasonic bath would clean this valve. I prepared a cleaning solution from detergent 5 g, sodium hydroxide 5 g and water 1.5 l. Three sessions in the bath left only a brown varnish on the valve.
The valve was so clean it slid straight back into the manifold.

I would never try cleaning an EGR valve unless the intake is very dirty. They foul up at about the same rate, so if you read the instructions and clean both together, then it's easy to figure out if the EGR valve needs cleaning again.
It should be done every cam belt service and if you don't have the Volvo tool, try a big pipe wrench!

To help free up the valve, use WD40, but then use brake cleaner (Or switch cleaner) to clean it. Use a new crush washer not a paper gasket and a new O ring for the intake. The bolts should be refitted using a low stregth Locktight to prevent corrosion.

If you have to use a pipe wrench, it's a good idea to have a new EGR valve (Often made by Pierburg) on standby. Some folks have even broken one of the 3 flanges using the Volvo approved tool, which is probably why their dealers always replace rather than clean EGR's.

Some mad engine modders clean their EGR's with the engine running !!
The Mod involves drilling a hole and fitting a small bolt in the intake that allows a fine plastic hose to be inserted all the way to the EGR. Then you use a can of Liqui Moly or 3M diesel EGR cleaner (Listed in their Pro systems) that already has the hose fitted to spray in solvent whilst the engine is revved up. Not a job for thee faint hearted and it causes a lot of smoke.

PS: Not had to clean my EGR for 150K km (I did get the intake done) cos a good blast on the Autobahn does that job. It also cleans up the turbo system.