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Do I need a Exhaust Gas Recirculation (EGR) Valve?


I have a Toyota Corolla 1997 CE, 52,000 miles. My car was dying at stops or low speeds due to low engine idle. Toyota dealer changed the “Idle air control valve”. This solved the problem.

However, they told me that when they were test driving the car, they suspected and later found that “EGR Valve” is getting stuck time to time. Of course, they suggested me to replace it, which is another four hundred US dollars. I could not do it because I did not have enough money. The mechanic at the dealer told me that if I am not going to fix it, I should have it disconnected. This way it is better for my car and “check engine light” will not come on. So, I listened to him. Now, “EGR Valve” on my car is disconnected. I do not feel any difference in engine, except that it idles little bit rough, but it does not bother me.

However, I am worried that having it disconnected will damage my car engine. Do I have a reason to worry about? I am planning to buy a brand new car after a year. I was wondering, if I can drive this car without an “EGR Valve” for a year without any problem.

I know that it will affect car’s emission. Honestly, I cannot care about the emission right now. I am on a tight budget. Moreover, I drove only total 52,000 miles in past 11 years. I do not think I releasing too much toxic gases to atmosphere.

I would really appreciate, if anyone can comment on my concern. Thank you very much for your time.

You could try running a can of SeaFoam (6 bucks a can at Wal Mart and it’s great stuff) through the intake as outlined on the can’s directions. This can often clean out and free up a sticky EGR.
If you do this your car will smoke for a short time afterwards. This is entirely normal.

Other than the emissions angle the critical part is that you do not hear any rattling sounds (like a rock in a can) that may occur when the engine is warmed up and under a load; passing someone, going uphill, etc.
If you do not hear any rattling there should not be a problem with it. If you do hear rattling then I would advise trying to get it repaired if the SeaFoam does not clear it up as a chronic, long term engine rattle can be detrimental to the engine.

The main purpose of the EGR is to allow some exhaust gas to recirculate back into the intake manifold when the car is under power. The overall effect is to lower the exhaust gas temperature, which reduces the formation of NOx and SOx compounds.

With the EGR disconnected, you should get a ‘Check Engine’ light come on for an EGR trouble code. Also, this will make the catalytic converter work harder due to higher exhaust gas temps and more NOx compounds than it was designed to handle. Converter burn-out is a real possibility. Also, I pity the exhaust valves. They are getting punished as well. Basically, this can wind up costing more than fixing the EGR, if that was really a problem.

BTW, is the CEL on? It should have gone on before you finished the first drive.

Cars ran fine for 65 years without EGR valves and so will yours. If you are worried about it, remove the valve assembly from the intake manifold and carefully clean the sliding “gate”. You can usually manipulate the valve with your fingers to check its operation. Also clean out the cavity and gas ports where you removed the valve from…

The only time this valve is opened is when you are at a steady cruising speed. At idle or under acceleration it is closed. If it sticks open at idle, it will cause rough ideling and stalling…

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While I agree that it’s possible to have a car that will suffer no problems due to an inoperative EGR I also think it varies on a car by car, case by case basis.

A few years ago the EGR tube sooted up in my Lincoln and it would not rattle no matter how hard the throttle was hammered.
On the other hand, when the EGR dropped in one of my son’s cars (Chevy) it rattled like mad before I replaced it, and enough of that rattling is eventually going to start doing some engine damage.

Maybe the EGR problem is caused by a lack of maintenance. It has a rough idle so faulty ignition parts, etc. could be the main contributor to the EGR problem.
If the OP decides to replace this valve they could consider this one.

Assuming the valve itself is actually bad, it looks pretty simple and straightforward to replace; 2 bolts, vacuum hose, and exhaust tube.

If you were a do-it kind of person, you might get the egr working properly by cleaning it. Here are pics of one person’s efforts at that:

Thank you for your reply. But, What is CEL?

Check Engine Light. It will go on if the EGR is disconnected. The engine management computer has sensors that will tell it the EGR is not functioning, and set a diagnostic trouble code (DTC), which will turn on the ‘Check Engine’ light (CEL).

Thanks. I should have guessed that. No, CEL was never on for any reason. Dealer told me that mechanic who diagnosed and repaired the “Idle air control valve” did not notice anything wrong about EGR valve during his diagnosis. However, the frontman who test drove the car after repair noticed that car was idling rough. Then, they checked and found that EGR valve gets stuck time to time (I had to believe that because sometime I felt little rough idling.). And, they suggested that it will cause trouble in future. I thought it was due to “Idle air control valve”. The dealer told me that they did disconnect EGR to make sure that CEL deos not go on. Honestly, I do not know how they did it! Thanks again.