Misfire/knocking noise
10-15-2018, 11:04 AM
#1
Junior Member
Thread Starter
Misfire/knocking noise
Hi all (first post here),
I have 2013 GL350 with about 95k miles. Yesterday, I drove the car back from a 500 mile trip. Stopped and shut the engine off for about 15 min and started driving again. While climbing a hill, the engine became a little shakey (sort of like a misfire), the transmission downshifted. I immediately took my foot of the gas pedal began braking to pull off to the side of road. As I did this, the engine shut off. When stopped the engine would not turn over. I could hear the starter click, but not turning of the engine. Battery voltage checked at 12.0V, No low battery sign ever popped on the dash. A tow truck gave me a jump start. The engine started but seemed a little shakey at idle. Alternator voltage and current are good varies between 13.5 and 14.2V and shows charging the battery. The engine did, eventually smoothen out at idle, but still misfires under load and also makes a knocking sound while misfire at 1600+ RPM. What could be causing this? Can a battery just completely die suddenly like this? I have no check engine lights either. Could it be a bad fuel injector?
The car had an oil and filter change using approved 229.51 oil (Mobil 1 ESP 5w30) and WIX oil filter at the beginning of the trip. The only thing that I can think of is that I ran 3/4 of a tank of biodiesel blend between 5 and 20% because I was in Illinois and couldn't find straight diesel. I have since filled with straight diesel, but the noise and misfire remain. Do I need a new battery?
Sadly the vehicle is 2 wks outside of MB COPO warranty!
Sorry for the long post, but just wanted to give all relevant history.
Thanks!
I have 2013 GL350 with about 95k miles. Yesterday, I drove the car back from a 500 mile trip. Stopped and shut the engine off for about 15 min and started driving again. While climbing a hill, the engine became a little shakey (sort of like a misfire), the transmission downshifted. I immediately took my foot of the gas pedal began braking to pull off to the side of road. As I did this, the engine shut off. When stopped the engine would not turn over. I could hear the starter click, but not turning of the engine. Battery voltage checked at 12.0V, No low battery sign ever popped on the dash. A tow truck gave me a jump start. The engine started but seemed a little shakey at idle. Alternator voltage and current are good varies between 13.5 and 14.2V and shows charging the battery. The engine did, eventually smoothen out at idle, but still misfires under load and also makes a knocking sound while misfire at 1600+ RPM. What could be causing this? Can a battery just completely die suddenly like this? I have no check engine lights either. Could it be a bad fuel injector?
The car had an oil and filter change using approved 229.51 oil (Mobil 1 ESP 5w30) and WIX oil filter at the beginning of the trip. The only thing that I can think of is that I ran 3/4 of a tank of biodiesel blend between 5 and 20% because I was in Illinois and couldn't find straight diesel. I have since filled with straight diesel, but the noise and misfire remain. Do I need a new battery?
Sadly the vehicle is 2 wks outside of MB COPO warranty!
Sorry for the long post, but just wanted to give all relevant history.
Thanks!
10-15-2018, 08:34 PM
#2
Junior Member
Thread Starter
I checked with a stethoscope—the knocking sound comes from the passenger side front of the engine. It becomes more pronounced when the engine ii at normal operating temp.
10-16-2018, 11:30 PM
#4
Super Member
Join Date: Jan 2014
Location: USA - Minnesota
Posts: 994
Received 319 Likes
on
248 Posts
2023 EQB 350 & 2014 GL350
Check the easy stuff first. Sounds like you have. If it's not the battery, check the fuel filter next.
The engine actually runs just fine on 5-20 biodiesel, but bio is also a powerful SOLVENT. If you have never run bio, your truck probably has plenty of completely normal diesel deposits in the fuel system.
Run a tank of bio for the first time in 95K and suddenly some of those deposits are set free and can clog filters, or worse, injectors. Meanwhile, and ironically, a driver in IL is doing fine because they've been running bio the entire time.
The engine actually runs just fine on 5-20 biodiesel, but bio is also a powerful SOLVENT. If you have never run bio, your truck probably has plenty of completely normal diesel deposits in the fuel system.
Run a tank of bio for the first time in 95K and suddenly some of those deposits are set free and can clog filters, or worse, injectors. Meanwhile, and ironically, a driver in IL is doing fine because they've been running bio the entire time.
Last edited by cadetdrivr; 10-16-2018 at 11:32 PM.
Just take it to Indy guy, probably couple of them to make sure if it can be fixed.....If it cant, then sell it of Craigslist...
Trending Topics
10-19-2018, 12:23 PM
#9
Junior Member
Thread Starter
Dealer did not give a specific diagnosis--just that the engine needs to be replaced. Service manager said "metal has gone through the engine" and that "the crankshaft is loose". Also, stated that without opening it up they could not determine extent of damage or cause. I'm less than thrilled with that explanation. I have asked to speak with master tech that did the diagnostic so I could understand how he came to that conclusion. I haven't heard back as yet. I intend to tow it back home today or tomorrow and start opening things to figure out what's up. Apparently, finding a low mileage used MB 3.0 liter diesel is not cheap either. No one I talked to has heard of rod knock or bearing failure at such low miles on a maintained engine--not that that helps much now.
Would a clogged fuel filter cause a knocking sound?
Would a clogged fuel filter cause a knocking sound?
10-19-2018, 02:16 PM
#11
Junior Member
Thread Starter
Finally spoke with the service manager. He states that the crankshaft has too much play. They figured this by moving the main pulley. They did not determine the cause--that would cost extra. The tech who actually did the work was not there today. The shop foreman was unavailable--he was too busy with "a very important diagnosis" I was told. I also talked with dealership sales manager re: trade-in value. Only $2000. Really frustrating!
10-21-2018, 11:06 PM
#13
Junior Member
Mb usa is not the dealer, two seperate entities. If the crank has excessive play sounds like a thrust bearing is gone. If it has fully dealer servixe history i cant imagine mb usa not stepping in. They will require a full teardown no doubt.
10-22-2018, 03:53 PM
#14
Junior Member
Thread Starter
Just got the return call from MB USA. They are offering $3k toward the purchase of another new or CPO Mercedes-Benz as a good will gesture. I explained my disappointment—politely, and asked the representative if he would ever consider purchasing or recommending to anyone another MB product if he were in my position.
Answer: “I understand, this is a very unfortunate situation...”
Answer: “I understand, this is a very unfortunate situation...”
