E.G.R. Valve - Tony Cooper
This rather expensive component (£106 + VAT and labour) has just been replaced on my son's 1.8 Astra to cure hesitant constant throttle use.

What does this valve do (Exhaust Gas Recirculation valve?) and where is it fitted?

A bit of education doesn't go amiss.

Thanks to you experts out there for any info.
Re: E.G.R. Valve - honest john
It's supposed to sen unburned hydrocarbons and crankcase gases back through the fuel system to the combstion chanbers so they get burned.

HJ
Re: E.G.R. Valve - mike harvey
Tony,
Just lost the first message somewhere, so here's another go. An EGR system is fitted to reduce NOx ( Oxides of Nitrogen) emmissions, which are the product of high combustion temperatures in modern engines, and very undesirable! Exhaust gasses are fed into the combustion chamber under certain engine conditions,usually full load, and this slows down the burn rate of the fuel, and reduces the NOx to an acceptable level. I'm not sure where it is fitted on an astra, or even if it has one, but it must connect the exhaust manifold with the inlet manifold somewhere.
Mike
E.G.R. Valve - David Lacey
Mike's got it spot-on!
I think a proportion of exhaust gasses are fed into the intake system under full load and cruise conditions to reduce NOx emissions
Many cars are now fitted with EGR coolers to reduce gas temperature
rgds
David
Re: E.G.R. Valve - Adam Going (Tune-Up Ltd)
Vauxhall EGR valves are developing a bit of a reputation ! They can sometimes be cleaned sucessfully (using carb cleaner or an ultrasonic tank) as they are often just sooted up with exhaust gasses, but often renewal is the only answer. I have seen it advised in certain quarters that the valve can be blanked off using a metal template between it and the cylinder head - this apparently improves driveability, but I suspect it could give rise to emission test problems.

The EGR is often sited on the rear (inlet) side of the cylinder head, taking exhaust gas internally through the head. Once removed it's mechanical operation can usually be checked using a vacuum pump.

Regards, Adam
 

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