Mech advises egr valve replacement. Engine is not missing ,running rough, nor is there any hesiation. What else would be an indication of a defective EGR valve. 1997 Pontiac Bonney
The physical symptom, since the car appears to run fine, would be possibly engine pinging when the engine is warmed up and under a load such as passing someone or going uphill.
This could vary as there are so many factors involved such as altitude, gasoline quality, etc.
The not so obvious thing would be related to emissions such as excessive NOX (oxides of nitrogen) etc.
The CEL may illuminate also.
If your engine is pinging under a load I would advise having it repaired. Hope that helps.
car does not ping under load. at 65 hit passing gear and climbed to 85 no problems incountered. Car runs great either city or highway driving. Mech says replace EGR valve
Is the CEL illuminating at any time? Is there any particular reason the mechanic was looking at the car and gave this diagnosis?
It is possible to have a defective EGR and not have any symptoms at all.
EGR valves reduce NOx when cruising at part throttle. That’s ALL they do. Cars ran without them for 70 years. They are closed at idle and when accelerating. If there is a problem, your CEL will come on. Save your money and find a new mechanic…
Did have a check engine light, Mech said o2 sensor was defective. Reset system drove 180 miles no light. 02 has not been replaced yet.I closely monitored all gauges. All normal.
The EGR actually does more than lower NOX. It lowers the combustion chamber temperatures. A faulty EGR may cause some cars to ping like crazy and others not so much if at all. It’s a crap shoot.
I have no idea why the EGR was diagnosed on this particular car. Short of having AutoZone pull the codes (it’s free) and if nothing comes up, and since the car is not pinging, I would not even worry about it at this point.