EGR-valve check? how?

855 TDI automatic 1997

Some weeks ago when having a look at the engine because of the low voltage at
the battery, I noticed rubber vacuum tubing in very bad condition, belonging to
the EGR system. I changed all the tubing accessible, even including an original
rubber part between EGR valve and stiff vacuum tube.

Then I read that one item during service at 270.000 km is "Checking the EGR
valve". The car does idle fine and except during heavy acceleration I cannot see
much of a smoke cloud behing me. It does not stall during acceleration.

How can the EGR-valve tested and can it hav a malfunction in a way that is
repairable? Used valves sell for about 60 Euros here, haven´t checked for the
price of a new.

Franz47

 

You can probably just ignore the warning.

The EGR is only there to reduce the amount of NoX in the exhaust gasses.
It does this by routing dirty exhaust gasses back into the engine (and
thus reducing the amount of oxygen). You can easily disable the EGR
valve by blocking the vacuum line or by putting a metal shield between
the EGR valve and the air intake.

I have done this (the metal shield) on my '97 S70 TDI with 315000 km.
This has drastically reduced the amount of soot and there were no
problems at all. In the Netherlands (where I live) the car is tested
annually on the amount of soot and not the the NoX levels.


Einstein

 

At least the soot they check here in Austria, I know for sure. Not sure about
nitrogen-oxide. In case I get problems with the soot and they do not measure NOx
I might do the metal shield trick, too.

Doesn´t the EGR also reduce the peak temperature during combustion because of
the highter specific heat of the exhaust gas compared to air?

Franz47