Do you hear a strange chirping at idle and during acceleration?
On the dashboard start lighting TCS and the Check Engine (P0401)?
It’s high time to check the EGR valve.
At the outset, a brief story, in order to explain what prompted me to clean the EGR valve…
Beautiful May afternoon, I rode quietly from work, I stopped at a traffic light, and suddenly I heard some strange trrrrr trrrr trrrr … .. What is going on !!! ???
I stopped at the bus stop, I lifted the hood up and listened from where place the exotic sound was coming 😉
I was able to quickly locate the place. Lower right corner of the plastic engine cover, which is the EGR valve. Reassured that it was „only” the ecological gadget… I got home. Apart from that, there was no any other symptoms.
My Mazda 6 2.0 CITD (136 hp) has electronically controlled EGR valve, but there are also versions mechanically operated. The difference is only in the sensor or its absence at the top of the EGR valve.
If you are in the similar situation as above-described symptoms, I suggest you start by cleaning the EGR valve, because it’s the simplest and fast way to check your EGR and it can really help you. For me, the first time it passed the exam 🙂 Finally, and so I ended up replacing, but after cleaning the valve still worked for 9 months. Used EGR in Poland costs from 80 – 300 zł, a new one… even I will not write, because you do not want to unnecessarily stress;).
The procedure described below is the same both for cleaning and replacement EGR valve.
1. Unscrew the plasctic engine cover:
2. The RF5C engine after removal the cover and marked the EGR valve:
3. Unscrew the big nut (size 36) on the bottom of EGR valve:
4. Then you have 2 nuts on studs, on which sits the EGR. Unfortunately, only unscrewing them will not do anything, because the pipe on which sits the EGR (on the bottom) is so stiff that it’s not possible to remove it. The solution is to screw the 2 extra nuts for the attack, and eventually remove the studs all over them 🙂
The following picture shows the screws are countered ready to remove with studs:
ATTENTION: behind the EGR valve is a thin metal gasket / pad, which ensures tightness of the exhaust gas flow. When removing the studs is best to put your hand to catch it. Removing it from the bottom of the engine took me an extra half an hour + has provided me a bonus as removal the lower engine cover…
5. Later you have only take out the plug from the sensor (in the case of a valve with a sensor) and remove the valve to replace it or clean.
6. Cleaning will take you only 10 minutes.
We begin by scraping the soot from the lower inlet valve, there is the most of it. I did it by small flat screwdriver. The second step is a thorough rinsing of the EGR valve in gasoline and cleaning it by brush from the bottom and inside. We are trying to reach, wherever it’s possible, and where we see the soot. After purification we check by pressing the top of the valve through the opening at the metal plate to see whether the valve is working at all. It’s hard, but it should be moving.
7. Cleaned or reinstall a new (used working) EGR valve, using the same sheet metal seal. There is no need to replace the seal, just clean it. An alternative option is to use the plug instead of the seal. Its purpose is to block the flow of exhaust gas into the air intake and engine, it looks as follows:
P.S. As curiosity – I rode about 3 months with clogged EGR with above plug. My feeling (perhaps subjective) was that my Mazda has done more bubbly as both on cold and on hot engine. However, I was forced to remove the plug and put back a simple seal, because I had on dashboard a combination of TCS and Check engine error. I connected the ELM327 and got information about the error P0401 (Exhaust Gas Recirculation – fault). Cleaning EGR gave nothing, after fault reset by removing the battery clamp, the error returned after about 50 km. After removing the plug and replacing the seal symptoms are gone.
Let there be no doubt as to whether this plug was guilty of all this confusion 🙂 For certainly NOT.
I used the plug after replacing the valve, so out of curiosity, because so many of them circulating myths and conflicting opinions, I decided to see for myself if it gives something or not. To sum up my view of the plug is slightly better, but maybe it’s just my subjective feeling 🙂 In mazda probably less popular, a lot of people use plugs for EGR to blinde it in their VW TDI or eg. Ford TDCI, you can see their popularity on auction sites.
At the end I have to add – Remember that this is only the tip text, and picking up any self repair is your own risk.
If you have some questions or comments that you would like to share, feel free below this text 🙂