E350 BlueTec Momentary Loss of Power
Thread Starter
Junior Member
Joined: Feb 2019
Posts: 34
Likes: 2
2012 E350, 2014 GL350
E350 BlueTec Momentary Loss of Power
Just bought this car and it was running great for the first 1500 miles. I knew the car needed replacement of the motor and transmission mounts due to rough vibrations when cold and at idle/stops. Otherwise the car ran fine.
So since the car was new to me I had an engine LOF performed followed by the mount change and a transmission filter with fluid change. The mount change was a remarkable improvement as the unwanted vibrations are gone.
Now for the current problem. Periodically there is a momentary loss of power as in a split second. This causes the car to buck and then back to normal. It happens more when cold and warming up but can also occur after warmed to normal driving temperature. I've discussed with the shop that did the transmission service and they say they put back the same amount of fluid that was removed plus they put the car on a computer to verify fluid levels. Before I take the car back to them I thought I'd post and see what others have experienced.. My opinion is as follows;
a) there is an unrelated problem and just coincident to the transmission service
b) the transmission fluid is low and there is occasional slipping of the converter causing the bucking / loss of power
c) the wrong type of fluid was used (I believe they should have used ATF134???)
d) Both b and c are factors.
e) there is an issue in the fuel system such as fuel filter is near clogged, bad fuel and/or fuel pump is acting out
Any inputs are appreciated and thanks,
Dan aka dofdear
So since the car was new to me I had an engine LOF performed followed by the mount change and a transmission filter with fluid change. The mount change was a remarkable improvement as the unwanted vibrations are gone.
Now for the current problem. Periodically there is a momentary loss of power as in a split second. This causes the car to buck and then back to normal. It happens more when cold and warming up but can also occur after warmed to normal driving temperature. I've discussed with the shop that did the transmission service and they say they put back the same amount of fluid that was removed plus they put the car on a computer to verify fluid levels. Before I take the car back to them I thought I'd post and see what others have experienced.. My opinion is as follows;
a) there is an unrelated problem and just coincident to the transmission service
b) the transmission fluid is low and there is occasional slipping of the converter causing the bucking / loss of power
c) the wrong type of fluid was used (I believe they should have used ATF134???)
d) Both b and c are factors.
e) there is an issue in the fuel system such as fuel filter is near clogged, bad fuel and/or fuel pump is acting out
Any inputs are appreciated and thanks,
Dan aka dofdear
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Joined: Dec 2005
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From: SoCal. Desert
'16 E350, gone: '03 c230k
When was the fuel filter last replaced? Might consider doing that first and chalk it up to maintenance if nothing else.
Sometimes I'd rather pay someone to do routine maintenance but rarely do just because mistakes happen, and if someone's going to make a mistake on my vehicle I'd rather it be me and I know about it. Hope that makes sense. I suspect you cannot check the fluid level with a dipstick, so you might have to top it off to be sure. I have yet to do this myself, but will when it comes time to service. The 7-speed transmission drain hole has a tube attached up inside. When the transmission is empty, a screw on filler attachment is used to pump fluid in to a level above the height of the tube on the drain. After idling for some amount of time to get the tranny fluid up to operating temperature you remove the drain plug, let whatever fluid is above the height of the tube to drain out, replace the drain plug, and level set (you can find videos on You Tube). Putting back in the same amount that came out isn't necessarily the best way to ensure the level is set correctly. If the level is indeed correct, and what I'd be most suspicious of is the type of tranny fluid used. I would ask them what type of fluid they used - do not offer up any brand or type of fluid, let them tell you.
Are you sure it's the tranny and not the engine stumbling?
Edit:
Cool graphic at the bottom of this page - https://www.fcpeuro.com/products/mer...tosin-7229late
Also a DIY: https://blog.fcpeuro.com/mercedes-7-...-transmissions
Sometimes I'd rather pay someone to do routine maintenance but rarely do just because mistakes happen, and if someone's going to make a mistake on my vehicle I'd rather it be me and I know about it. Hope that makes sense. I suspect you cannot check the fluid level with a dipstick, so you might have to top it off to be sure. I have yet to do this myself, but will when it comes time to service. The 7-speed transmission drain hole has a tube attached up inside. When the transmission is empty, a screw on filler attachment is used to pump fluid in to a level above the height of the tube on the drain. After idling for some amount of time to get the tranny fluid up to operating temperature you remove the drain plug, let whatever fluid is above the height of the tube to drain out, replace the drain plug, and level set (you can find videos on You Tube). Putting back in the same amount that came out isn't necessarily the best way to ensure the level is set correctly. If the level is indeed correct, and what I'd be most suspicious of is the type of tranny fluid used. I would ask them what type of fluid they used - do not offer up any brand or type of fluid, let them tell you.
Are you sure it's the tranny and not the engine stumbling?
Edit:
Cool graphic at the bottom of this page - https://www.fcpeuro.com/products/mer...tosin-7229late
Also a DIY: https://blog.fcpeuro.com/mercedes-7-...-transmissions
Last edited by mtnman82; Apr 15, 2020 at 08:31 PM.
Thread Starter
Junior Member
Joined: Feb 2019
Posts: 34
Likes: 2
2012 E350, 2014 GL350
Thanks for replying. No, I'm not sure if its an engine stumbling. Since the last thing done to the car prior to the problem was transmission I am hoping to rule this out but anything is possible. Dan
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Joined: Jul 2014
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From: Tucson, AZ
'20 X5 M50i; '17 Ram 3500; Golf Cart; Bikes; Scooters
You say high miles, but we don't know what that number is. May help to include that.
As stated previously...start with the fuel filter, and a high quality diesel fuel injector cleaner, as your injectors may be dirty.
I doubt the trans fill has an impact on the engine, but it may be related to shift points.
My Bluetec has a throttle lag when punching it, but no bucking or stumbling.
I use the Ford Lubricity additive every tank to maintain the fuel system and help with mileage, and change the fuel filter according to the book.
Let us know the results after your work.
As stated previously...start with the fuel filter, and a high quality diesel fuel injector cleaner, as your injectors may be dirty.
I doubt the trans fill has an impact on the engine, but it may be related to shift points.
My Bluetec has a throttle lag when punching it, but no bucking or stumbling.
I use the Ford Lubricity additive every tank to maintain the fuel system and help with mileage, and change the fuel filter according to the book.
Let us know the results after your work.
