Could a clogged and faulty egr cause a clank, or thunk?
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Joined: Oct 2011
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From: Portland, OR
2015 GL350 (mine) 2006 E320 CDI (20 year-old son took from me)
Could a clogged and faulty egr cause a clank, or thunk?
A week ago the CEL on my 2015 GL350 (61K miles) came on while I was spending the weekend away from home. The dealer's SA just updated me that they solved the issue under warranty. Apparently, the egr they replace a year ago at around 53K miles under the emissions recall warranty had a bad spring and was already 50% clogged. Is it reasonable that the random "clank" and "thunk" I felt a 3-4 times over ~300 miles (that seemed almost like it was transmission related) was caused by a clogged and faultIy egr valve / spring?
Background:
My GL350 was getting great 27 mph fuel economy, power and idling seemed fine as well. The other odd symptom was a one point I was climbing an easy incline and it felt like my GL was hunting for the gear yet the RPM stayed the same on the tachometer. I could never reproduce these symptoms. In fact I drove the last 70 miles home and then to the dealer without noticing anything other than the CEL. The clank and thunk just seemed more pronounced than egr symtoms I read about.
Here is the mechanic's summary from today:
"unable to verify customer concern, check engine light was not on when vehicle was brought in, connected sds and battery charger, performed short test, found code 100b00 upper limit of mass air flow sensor right, and 101300 lower limit mass air flow right, performed test in xentry for sensor and senor passed test, xentry tells to check for leak in charge ari system, found no leak, next step in guided test was to check the left mass air sensor, sensor passed test, next guided test test the EGR system, fails test, tried test again and it keeps failing, replaced mass air flow sensor with known good control unit for testing, reset MHD, tried egr test again, and it still failed, xentry showed to replace the egr valve, replaced valve and reinstalled old mass air sensor, repeated test, and it still failed, further xentry test said to clean the egr elbow that goes into the intake, found it to be 50% clogged by carbon, cleaned elbow and reinstalled, repeated test and still failed, cleared codes and drove the vehicle for 10 miles and retired test, passes test every time now"
Regrettably, my GL350 was at the same dealer for CEL a month ago. On that visit the CEL issue was resolved by replacing a faulty O2 Sensor, also replaced under warranty. Yes, I'm feeling they missed egr a month ago. Which leaves me less confidence in what they tell me today - as much as I appreciate services visit resulting in no-charge warranty work.
Background:
My GL350 was getting great 27 mph fuel economy, power and idling seemed fine as well. The other odd symptom was a one point I was climbing an easy incline and it felt like my GL was hunting for the gear yet the RPM stayed the same on the tachometer. I could never reproduce these symptoms. In fact I drove the last 70 miles home and then to the dealer without noticing anything other than the CEL. The clank and thunk just seemed more pronounced than egr symtoms I read about.
Here is the mechanic's summary from today:
"unable to verify customer concern, check engine light was not on when vehicle was brought in, connected sds and battery charger, performed short test, found code 100b00 upper limit of mass air flow sensor right, and 101300 lower limit mass air flow right, performed test in xentry for sensor and senor passed test, xentry tells to check for leak in charge ari system, found no leak, next step in guided test was to check the left mass air sensor, sensor passed test, next guided test test the EGR system, fails test, tried test again and it keeps failing, replaced mass air flow sensor with known good control unit for testing, reset MHD, tried egr test again, and it still failed, xentry showed to replace the egr valve, replaced valve and reinstalled old mass air sensor, repeated test, and it still failed, further xentry test said to clean the egr elbow that goes into the intake, found it to be 50% clogged by carbon, cleaned elbow and reinstalled, repeated test and still failed, cleared codes and drove the vehicle for 10 miles and retired test, passes test every time now"
Regrettably, my GL350 was at the same dealer for CEL a month ago. On that visit the CEL issue was resolved by replacing a faulty O2 Sensor, also replaced under warranty. Yes, I'm feeling they missed egr a month ago. Which leaves me less confidence in what they tell me today - as much as I appreciate services visit resulting in no-charge warranty work.
