EGR Valve


For some time now ,I have been following a thread on Facebook concerning the EGR valve, which pertains to diesel-engined cars. In the thread, they mention about disabling the EGR (exhaust gas recirculation) valve by replacing it with a block-off plate. Hmmm… let’s step back for a while.

The EGR valve is a device that allows a certain amount of exhaust gas to reenter the combustion chamber to lower the combustion temperature through the intake manifold. This lowers the amount of nitrogen oxide. Nitrogen oxide starts to form when combustion temperatures are at 2,140 degrees Fahrenheit. But when you reach 2,500 degrees or above, it is produced in excess. The EGR system controls the production of nitrous oxide by diluting the air fuel mixture with small amounts of exhaust gases that are inert. This produces a rich mixture thus reduces combustion temperature. Oxygen is the high temperature-causing element in the air/fuel mixture. The valve can be operated by an engine vacuum source. Vacuum pressure changes with engine speed. As speed increases, more fuel and air mixture is burned and then combustion temp increases. Or it can be controlled by an electronic vacuum switch that detects engine temperature. In a nutshell, it helps lower exhaust emissions and helps keep combustion temperature at bay.

A faulty EGR valve can cause the engine performance to falter. Engine stalling, surging or detonation. What can cause the EGR valve to fail? Since exhaust gases pass through the valve, soot can build up and cause it to fail. Usually cleaning the valve itself and the other parts related to its function regularly can keep it in good working order. About every other oil change. But if you notice that it needs servicing more often, then that might be a sign that something is not working properly. Condemning the EGR is not a solution if it starts giving you problems. Most mechanics consider it a useless device because they don’t fully understand the function and purpose of the device. But the engineers added that to the design of the engine for a purpose. So they must know something that we don’t.

For those considering condemning the EGR valve, better think twice. Especially for those with engines with electronic control units (ECUs). Some of them have backpressure sensors to help operate the EGR valve for a more optimum performance. The ECU is watching all the parameters of the engine. Almost all sensors that can give feedback to the ECU can double check other systems. Condemning it may give you more problems rather than solving them.

Change of pace…
Just to share something with you… being a hoarder that I am. I chanced upon these wrenches at a shop selling surplus power tools and equipment. Now, chances are these shops don’t sell automotive tools like wrench sets. But this shop had them. What is special about them are the ends have a ratchet at both ends. I think they call these gear tech… I’m not sure. Besides having a double end ratchet, they can be angled and one piece has four bolt sizes: eight millimeter, 10 millimeter, 12 millimeter and 13 millimeter for the smaller one; and 16 millimeter, 17 millimeter, 18 millimeter and 19 millimeter for the bigger one. Now, I have seen these kinds of wrenches in some tool stores but not the double ended ones, flex head and multiple with multiple sizes. Now, I don’t use them to tighten and loosen bolts. The one with smaller sizes was the only one that I saw in the shop. The KYK, Lota and Creston brands have these gear tech type of wrenches but you would have to buy one for each size that you need. This was cheaper. But I still plan to get another set of these kinds of wrenches. I have an old Lota catalog and I know they have the ones with the flex head and the stubby ones. If you guys love going to shops that sell tools and other stuff you may need, and you do find that special thing that you say “must have,” I tell you get it! Feel good about it! Worry about it later why you bought it when you get home…I felt good about it.


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