Hey all,
I have a 2009 MB 2.3L Duratec Automatic Wagon.

SOUND OF RATTLE HERE
Sound appears to be right side of engine bay, front of engine area.

Not long after I bought it (used), I noticed an intermittent rattle/ single "tink" sound, normally after I would either accelerate lightly, or back off the accelerator a little bit,such as like going through a roundabout.
Seemed to happen only after I was driving a while, when engine was nice and warm. It only ever did it once in a while and was hard to notice (couldn't even really hear it over the aircon).

Months go by and along the highway, the rattle went crazy (slow moving traffic) The temp guage stayed in the middle, but the car started playing up, I pulled over and realised the engine was cooking. I think the coolant had spewed out to the point it wasn't registering as hot on the temp guage.
Long story short, I replaced head gasket, had head machined, and replaced thermostat and waterpump for good measure. Fresh oil and filter of course.I
Seemed to fix the rattle, for a short while.

In my mind, I was concerned it was the timing chain, so I very recently replaced that, with the tensioner and oil-pump chain. 5 minutes into the first drive, I could hear the same rattle still. Typically between 2-3k revs, and seems a little worse when its hot outside/ engine is warm.

This sound ONLY happens when driving/ under load, and seems to be a little worse if going uphill. I can throw it in neutral and rev it out and engine sounds good. 
I can feel a little bit of viabration throught the steering wheel, but nothing bad (less since I replaced timing chain) I cant notice anything obvious with the engine mount, there doesnt feel to be any play/ feels really firm but thats just trying to wiggle it by hand with a jack under the engine. That said, im thinking it could be the engine mount as it only happens under load?

There is a good explaination and very similar sound in this video - https://youtu.be/vEb15NgsNkU?si=_OIELzw_XuPQxMfB&t=156


The fact that it only happens under load indicates that it would have to be a mount, bracket or the transmission (hopefully not), right? Ive heard some people have similar sound issues with alternators, steering pumps, knock sensors, ignition timing etc.Thinking of taking it into a mechanic but wanted to get some opinions here first.
Thanks!

On 1/9/2024 at 8:39 PM, thenm8r said:

Hey all,
I have a 2009 MB 2.3L Duratec Automatic Wagon.

SOUND OF RATTLE HERE
Sound appears to be right side of engine bay, front of engine area.

Not long after I bought it (used), I noticed an intermittent rattle/ single "tink" sound, normally after I would either accelerate lightly, or back off the accelerator a little bit,such as like going through a roundabout.
Seemed to happen only after I was driving a while, when engine was nice and warm. It only ever did it once in a while and was hard to notice (couldn't even really hear it over the aircon).

Months go by and along the highway, the rattle went crazy (slow moving traffic) The temp guage stayed in the middle, but the car started playing up, I pulled over and realised the engine was cooking. I think the coolant had spewed out to the point it wasn't registering as hot on the temp guage.
Long story short, I replaced head gasket, had head machined, and replaced thermostat and waterpump for good measure. Fresh oil and filter of course.I
Seemed to fix the rattle, for a short while.

In my mind, I was concerned it was the timing chain, so I very recently replaced that, with the tensioner and oil-pump chain. 5 minutes into the first drive, I could hear the same rattle still. Typically between 2-3k revs, and seems a little worse when its hot outside/ engine is warm.

This sound ONLY happens when driving/ under load, and seems to be a little worse if going uphill. I can throw it in neutral and rev it out and engine sounds good. 
I can feel a little bit of viabration throught the steering wheel, but nothing bad (less since I replaced timing chain) I cant notice anything obvious with the engine mount, there doesnt feel to be any play/ feels really firm but thats just trying to wiggle it by hand with a jack under the engine. That said, im thinking it could be the engine mount as it only happens under load?

There is a good explaination and very similar sound in this video - https://youtu.be/vEb15NgsNkU?si=_OIELzw_XuPQxMfB&t=156 geometry dash scratch


The fact that it only happens under load indicates that it would have to be a mount, bracket or the transmission (hopefully not), right? Ive heard some people have similar sound issues with alternators, steering pumps, knock sensors, ignition timing etc.Thinking of taking it into a mechanic but wanted to get some opinions here first.
Thanks!

I have I think the same problem but it happens when I first pull away and if I put it in reverse. I get a “clonk” noise. Almost like a worn cv joint but only clonks once. My car is 2018 Ford Escape