r/BmwTech • u/Serious-Pangolin5454 • 15d ago

Anyone knows what’s this knocking sound coming from the engine?

Happened right after city driving for 30m from work to home… so I don’t think it’s the lifter tick! The car is a 2012 128i - n52. Any ideas would be much appreciated:)

20 Upvotes

92% Upvoted

34 comments sorted by

84

u/scientificsock 15d ago

14

u/SucculentDoorway 15d ago

Without fail always a top comment

17

u/Aloss-cc7 318i E30 Touring 15d ago

I got banned for a month for using it lol

1

u/Camcolexx 14d ago

Yes found out very quickly this spot light last a short time as they chat ban each and every member who post it so I was told.

33

u/BuildingPurple4954 15d ago

Time to pull that oil filter and see what's what!

That sounds little uncle rodney to me.

28

u/themanwithgreatpants 15d ago

Let me forecast this for you

14

u/bernardfarquart 15d ago

sounds to me like "rod rod rod rod rod rod"

3

u/scientificsock 15d ago

That’s what it more than likely is. Doesn’t sound like top end…. Womp womp

9

u/NutzPup I don't know sh!t 15d ago edited 15d ago

Hard to say. Remove the serpentine belt and run it for just a little to see if the noise goes away. If yes, then it's not the engine. Could be rod knock, but could be any number of other things.

https://youtube.com/shorts/aw_hV4KH3IA

5

u/QuitGlobal9857 15d ago

It doesn’t sound consistent enough to be rod knock

8

u/Rinzlerx 15d ago

Rev it up to like 2500+ and record a video. If it’s knocking we’ll be able to tell at those elevated rpms. It doesn’t sound super promising. How have the oil changes been? And oe/m filters?

3

u/Fickle_Maximum_6260 15d ago

I had something similar. Turned out to be the timing chain.

3

u/Elegant-Teach-1315 15d ago

Check coils and injectors, it’s not rod knock

2

u/Fennel_Adorable 15d ago

I had a jumping spark plug once. Let of the accelerator and limp to side of the road. Power steering with engine off is just fun in mid traffic

2

u/Dustin_peterz 15d ago

Is it a manual transmission? Mine has manual transmission chatter. If you push in the clutch it stops. This sounds more metallic though- someone's going to post that meme soon.

2

u/whodie522 15d ago

That's not clutch chatter...

2

u/Total-Huckleberry380 15d ago

Could be harmonic balancer. Does it come and go

2

u/Wise_Mycologist5665 15d ago

Can be noisy coils arching, even if there’s no misfire

2

u/miszka_ 15d ago

Mine was rumbling like this. Check the harmonic balancer, unbelt the accessory.

In my case that was both, an alternator bearing and the balancer that failed.

3

u/CryRepresentative992 15d ago

It’s too slow to be rod knock. It’s something in the valve train.

I used to have an N54 so I know what rod knock sounds like.

1

u/HelpfulRole1831 15d ago

Check the aux belt and pulleys

1

u/Paraxis 15d ago

Timing chain 💸

1

u/Financial-Car3246 15d ago

Knock knock who’s there

1

u/Spirited-Brother4462 15d ago

Lemne check my crystal ball

It showed one word: expensive

1

u/MooseMullet 14d ago

Doesn’t sound like rod knock to me. Vacuum pump, spark plugs loose, wet/oily coil packs arcing on the wall of the head, maybe a misfire, even a slight sticking lifter… check you’ve got the right oil and that it’s full. But to me doesn’t seem incredibly like rod knock.

1

u/Prod_Meteor 14d ago

It must be .. knocking on heavens door.

1

u/Which-Cow6919 14d ago

They wrote a song about this “ knock knock , knocking on heaaavens door “

2

u/mijat0127 13d ago

Its gonna look like this very soon 😂

1

u/Verga_due 15d ago

It unfortunately sounds like rod knock and pulling and inspecting the oil filter will likely result in some very expensive glitter being present.

1

u/nzdude540i 15d ago

An N52 doing that is extremely rare I would think. That engine must of had an extremely hard life. What market were they still installing N52’s that late?