A45 engine knock please help !!!!

[tezbo]

Hi guys

New member here looking for some advice.i have owned my car for nearly 5yrs maintained properly the lot. After using my car daily for a few weeks to get to work mainly motorway I noticed it starting to sound like a wagon while idling sounding normal again when accelerating this was happening for about week. One evening on the way home I left the motorway and onto normal roads then the noise started. I know videos on phones doesn't do much but here's and example. Taken to 3 garages and all given different diagnosis don't think they wanted anything to do with the car tbh. Any help will be appreciated before I take it to the stealership

 

[tezbo]

One is from engine bay one is from inside the car

Hi guys

New member here looking for some advice.i have owned my car for nearly 5yrs maintained properly the lot. After using my car daily for a few weeks to get to work mainly motorway I noticed it starting to sound like a wagon while idling sounding normal again when accelerating this was happening for about week. One evening on the way home I left the motorway and onto normal roads then the noise started. I know videos on phones doesn't do much but here's and example. Taken to 3 garages and all given different diagnosis don't think they wanted anything to do with the car tbh. Any help will be appreciated before I take it to the stealership

 

[malcolm E53 AMG]

Could be the knock sensor(s) needs replacing

 

[AMGeed]

+1 for Knock sensor.
It really needs looking at by a Mercedes specialist (avoid main dealer if possible)
What's your location in case someone here can recommend a good specialist?

 

[tezbo]

Thanks for the help guys I'm based in Bury Manchester. Iv rang all the local specialist and roughly explained the problem and all said they won't touch it due to being tuned all they would do is fit a new engine

 

[AMGeed]

Thanks for the help guys I'm based in Bury Manchester. Iv rang all the local specialist and roughly explained the problem and all said they won't touch it due to being tuned all they would do is fit a new engine

SPR Autos in Stockport is a very good Merc specialist.
Worth a call and ask him to take a listen for some advice on best way forward.
Not sure he's taking on new customers such is his popularity.

MSL Performance would probably help but they are in Birmingham.

 

[tezbo]

The diagnosis I have had so far is crank pulley bearing, TOP end bearing both suggested engine rebuild. If it helps any further the noise is loudest on tick over no power loss no limp mode just that noise which seems to go away around 30mph

 

[AMGeed]

Might be worth replacing the knock sensor and seeing if that cures the problem.
They are pretty cheap for an A45.

https://www.euspares.co.uk/parts-catalog/knock-sensor-15025/mercedes-benz/a-class/a-class-w176/114960-amg-a-45-4-matic-176-052

 

[tezbo]

Yes worth a try definitely as this is a new diagnosis and the cheaper option to start lol. Thank you for the help

 

[arion]

Sorry, that sounds like bad rod bearings, remove oil filter and check for metal shavings to confirm.

 

[tezbo]

Sorry, that sounds like bad rod bearings, remove oil filter and check for metal shavings to confirm.

Ooo now this is the reply I wasn't looking forward too I have been avoiding doing that holding on to the slight glimmer of hope that it is something simple. Again thank you for your input/advice I appreciate all of it

 

[Blobcat]

Sorry, that sounds like bad rod bearings, remove oil filter and check for metal shavings to confirm.

It does sound a little like my Landy when the big end bearings went…

 

[LostKiwi]

Definitely sounds like one rod bearing. Not as rowdy on my V8 Range Rover when all 8 were knackered but very similar sound.

Do not drive it. Continued driving risks chucking a rod.

 

[tezbo]

It does sound a little like my Landy when the big end bearings

Definitely sounds like one rod bearing. Not as rowdy on my V8 Range Rover when all 8 were knackered but very similar sound.

Do not drive it. Continued driving risks chucking a rod.

Thank you I kinda have a gut feeling this is going to be the problem. I have a few friends who tinker with cars not mechanics but have good knowledge and know there way around a engine and without actually stripping it down a couple of them have said this issue. My only concern is wouldn't it throw a code or at least go to limp mode if it was engine problems being a Mercedes or is that just me wishful thinking

 

[LostKiwi]

Thank you I kinda have a gut feeling this is going to be the problem. I have a few friends who tinker with cars not mechanics but have good knowledge and know there way around a engine and without actually stripping it down a couple of them have said this issue. My only concern is wouldn't it throw a code or at least go to limp mode if it was engine problems being a Mercedes or is that just me wishful thinking

Wishful thinking.
Yes it will throw codes for some things but for pure mechanical issues they won't necessarily do it.

If it impacts emissions, results in fuel pressure or boost pressure or mixture variations it'll throw a code but as the piston still goes up and down and is still burning fuel it won't.

 

[LostKiwi]

As a possible quick and dirty test remove the spark plugs. Turn the engine to 90°after TDC. With a long screwdriver push the top of the piston down for each cylinder. If it moves the bearing is shot. Rotate another 180 degrees and repeat.
The first time will test 2 cylinders, the second time the other two.