Knocking sound from engine

aminjafer5441 (Amin Jafer) 2022-07-08 21:29:21 +0500 #1

Anyone have an idea what it could be? (Video link provided) Usual suspects are connecting rod bearings or crank main bearings. However this sound is very loud on cold engine and almost disappears when the engine is warm, which is strange. Also the engine has no symptoms of power loss or other issues so far nor any oil consumption nor any loss in oil pressure.
What could be ways to determine the source of the noise for sure.
I tried to remove the injector/spark plug connector of each cylinder one by one but the sound remains there regardless of which cylinder is disabled.
I've tried to determine for any play in the connecting rods by removing the sparks plugs, inserting a metal rod into the combustion chamber, and keeping the piston just past the TDC position. Then I tried to push the piston down to check if any play or click sound could be heard, but there was none.
I don't have the time currently to drop the crankcase and inspect the bottom end. Does anyone have any idea how else to check without disassembling the engine?

https://drive.google.com/file/d/1gO0xL6J6oolWMSzkQvYmhKUdkNbcwCrs/view?usp=sharing

Xulfiqar (Xulfiqar) 2022-07-09 03:33:37 +0500 #2

Its piston slap.

aminjafer5441 (Amin Jafer) 2022-07-09 10:25:41 +0500 #3

Could this noise be reduced by using heavier weight oil? Currently I'm using 5w30, thinking of switching to 10w40

Xulfiqar (Xulfiqar) 2022-07-09 12:17:20 +0500 #4

Nothing except repair can silence this noise.

aminjafer5441 (Amin Jafer) 2022-07-09 12:34:05 +0500 #5

Yup, kind of what I was expecting. I think I'll run it till the noise becomes constant on hot engine even and then think about repair since this would basically be a complete overhaul.
Thanks for the valuable info!

ifadey (Fawad) 2022-07-10 15:33:24 +0500 #6

I suggest you to get it repaired without delay. Leaving piston slap can further damage the cylinder walls. You don't want to be in a situation where you have to replace the block.

aminjafer5441 (Amin Jafer) 2022-07-11 22:46:05 +0500 #7

It's a tough call. I've driven the car for 30k km like this and it might run that much more. Once the engine is torn down it is basically a complete overhaul and with the kind work the local shops do it won't last much longer after repair either. I might try to get a replacement engine but not sure if k10 engine is available in market

aminjafer5441 (Amin Jafer) 2022-07-11 22:47:52 +0500 #8

@Xulfiqar would you happen to have any recommendations for a shop in islamabad to have it inspected and/or repaired if I find it feasible?
Also is the K10 engine assembly available in market like chah sultan ?

Xulfiqar (Xulfiqar) 2022-07-11 23:29:19 +0500 #9

@Nomi or @rajaatta @dani_kk can help you out.

aminjafer5441 (Amin Jafer) 2022-07-11 23:47:48 +0500 #10

@rajaatta and @dani_kk would you happen to have any suggestions for this issue?

dani_kk (Dmotorsports) 2022-07-12 17:42:06 +0500 #11

Dear suggestion here would not be possible. But if you tend to bring the car out for inspection. Then forsure I can pin point the noise along with solutions.

aminjafer5441 (Amin Jafer) 2022-07-12 19:51:30 +0500 #12

Yup I agree! Will your shop be open tomorrow?

dani_kk (Dmotorsports) 2022-07-13 19:20:15 +0500 #13

We will resume from Saturday or Sunday

rajaatta (Raja Atta) 2022-07-20 12:40:46 +0500 #14

It's piston slap along with connector rod bearing noise started

aminjafer5441 (Amin Jafer) 2022-07-20 23:02:35 +0500 #15

Not getting the time to get it officially diagnosed at a workshop. In the worst case of rod/knock and or excessive cylinder wear caused by piston slap, what options do we have for repair? Is new engine assembly available in market for local wagon R?

rajaatta (Raja Atta) 2022-07-21 14:35:15 +0500 #16

Hmm local wagon r swap is not available in the market so if the mechanic is knowledgeable then rebuild is the best option

aminjafer5441 (Amin Jafer) 2022-07-21 22:14:13 +0500 #17

@dani_kk thanks for pointing out the issue with the alternator bearings. In our diagnosis today we weren't able to confirm the noise as rod knock and I guess that is a good thing Will try to determine if the alternator is the culprit for the knocking sound on cold startup also.

Xulfiqar (Xulfiqar) 2022-07-21 23:36:59 +0500 #18

mechanics use the oldest tool called a stethescope to identify such noises. Do you own one?

aminjafer5441 (Amin Jafer) 2022-07-22 20:11:19 +0500 #19

I have a stethoscope for a BP machine but I'm guessing that won't work for an engine. We could feel a distinct vibration (like grinding) by placing a long screwdriver on the alternator housing which was not there on other parts of the engine like the water pump. I have yet to try and start the engine when cold with the generator belt removed which should kill/reduce the noise if it is the culprit. The distinct tapping/knocking (metal on metal) sound caught on the camera is strangely not noticeable much at all if we observe it in person.

Xulfiqar (Xulfiqar) 2022-07-22 22:22:05 +0500 #20

Its the same stethescope, you have to remove the pad and install a rod in its place.

Buy a junked one and make a mechanic stethescope from it.