2016 Ford Fiesta engine rattling

[Qui]

Hello,

since a week my Ford Fiesta from 2016 has some engine like issues. From time to time the engine and car vibrates and has a rattling noise. I haven’t figured out when it does it as if only happens from time to time.

if the car is restarted/start stop function the noise goes away and the car sounds normal again.

does anyone have any tips?

 

[Handy Andy]

...we are presuming you have removed all other possiblities of problems that add to this condition - like oil level checks and transmission appears to be in working order onto all belts are not binding and you've got no loose wires or spark plugs cracked or failed causing it to stall...

Could be an engine mount - onto a bad alternator or water pump onto even the AC compressor - all of them drag on the serpentine belt so you might need to make some closer inspections.

This may also mean several other things including coolant issues and hoses to the intake that may have cracked or collapsed

The rattle can be from the motor mounts shaking onto the drag on the serpentine belt when the bearings on the affected system, engage at the belt and so the engine senses the idle speed start to drop and adds more throttle to compensate. You hear a chatter sound from the belt slipping on the affected pulley.

If left to itself this condition will eventually set a check engine light

 

[Qui]

So oil levels etc all check out. Oilfilter has been changed, new air filter, a new High pressure fuel pump. And the problem still remained.

today I changed the Coils and sparkplugs, thinking it might have to do with the spark. But again the problem is still there. The car sounds as if it runs on 2 cylinders or something.

today I did figure out if meanly acts up after a hard corner or a big speedbump.

 

[SyntheticAtmosphere]

I would first clean and reinstall the ground connections under the battery. Also clean and verify the battery connections are good. If you are still on the original battery, you are in its end of life days. Have it tested.
Sounds to me like you may have a coil harness ground problem. Could also be a broken wire or short in the wiring.

 

[Qui]

Update: checken all wires and wiring and everything seems to be fine. also the coil and sparkplug change hasn’t helped.

did notice now that when the vibration and noises are present that if I keep driving for 2 min the vibrations and noises go away.
Also when shutting down the car if it js vibrating and noisy the noises keep rattling and vibration of a little while after the engine is shutdown… could it be something with the radiation fan or blower motor?

 

[Handy Andy]

could it be something with the radiation fan or blower motor?

Hmmm... several approaches here...read thru this first then decide on how you want to tackle this...

• You know you could have several places where the rattle can be from - you've mentioned two - we've talked about Motor mounts - even bad belts so with the process of elimination - you mention fan and blower - remember that this occurs as you're driving. It can be from many sources - it can also be a suspension problem.

If the Fan is running - and you hear that rattle - that would mean a Radiator fan or shroud, or both - replacement.

Considering the year - might be a good idea to replace both.

To check for that noise requires someone to be listening in the front with the Hood open so they can see operation of the AC and fan.

The Fan itself uses a relay from the main Fuseblock in the engine compartment - and when hot it comes on - AC it comes on - both should be the same speed - high speed.

While it's running and warmed up - have someone turn on the AC full - blower too - on HIGH - operate the settings to force air thru the various vent configurations - then listen for that rattle. Then just try to localize it.

It is not uncommon to have a bad blower - or debris in the motors housing - for we've seen pens, small change - even petrified french fries (yes food) in the blower housing - stuck in the bottom right by the cage of vanes the motor sits in.

The upper vent being a single vent with a wide horn spray for air - makes it highly likely the captured item can cause a jam or rattle as you drive because it may have cleared the cage housing but any type of bump makes it rattle.

The rattle can be even from the motors the operate that housing - it's a drum with ports in it that rotates using these smaller stepper motors to open vents or ports so you feel the air come out of those different ports when you change from floor to console to defrost and combinations thereof. You could hear a rattle as the debris in the bottom of that housing rolls along, trying to find it's own center of gravity to rest on the bottom of that housing.

However, if you can't recreate the noise except by driving - it may be a strut mount or a control arm bushing going out that needs to be serviced. You hear it seemingly throughout the vehicle because it's banging on the frame or it's housing.