BMW N53 cold rattling sound 1800-2000rpm

Jerremy175 · 10-23-2025, 05:54 AM

Hello guys,
I have question about weird rattling sound that happening only during the cold run when the car stay for few hours. Rattling sound appear only between 1800-2000 rpm, after the 30-60 sec. the rattling dissapear. Car runs good, no issue.
I already repleace entire timing chain with rail and oil chain with rail, rattling noise is still there same.
I am worried that it could be rattling from rod bearing, but i am not sure. The noise first appeared last winter in January 2025 and never changed to be louder or change characteristic.
Someone meantion that it could be piston slap, but i never heard that N53 has somethink like this.
Last weekend i changed the oil with filter and i found few really tiny piece of metal (few was ferous metal and few maybe aluminium) and also oil had somethink like metallic touch.
Is it really rod knock or it could be piston slap and is normal to hear that?
I am ready to disassembly the bottom of engine and check the condition, but I don't want to interfere unnecessarily to rod bearings.

Phil325i · 10-24-2025, 03:57 AM

Could it be chain rattle? Have you thought about replacing the timing chain tensioner? I replaced mine at 125,000 as preventive maintenance. It's an easy DIY job...

Jerremy175 · 10-24-2025, 07:15 AM

I already replace whole timing kit together with oil kit. Tensioner is new OEM.

Jerremy175 · 10-24-2025, 07:17 AM

Is it possible that new OEM tensioner is also bad and makes same noise as older one?

10-23-2025, 05:54 AM	#1
Jerremy175 Registered 0 Rep 3 Posts Drives: BMW E92, N53B30 Join Date: Oct 2025 Location: Czech iTrader: (0)	BMW N53 cold rattling sound 1800-2000rpm Hello guys, I have question about weird rattling sound that happening only during the cold run when the car stay for few hours. Rattling sound appear only between 1800-2000 rpm, after the 30-60 sec. the rattling dissapear. Car runs good, no issue. I already repleace entire timing chain with rail and oil chain with rail, rattling noise is still there same. I am worried that it could be rattling from rod bearing, but i am not sure. The noise first appeared last winter in January 2025 and never changed to be louder or change characteristic. Someone meantion that it could be piston slap, but i never heard that N53 has somethink like this. Last weekend i changed the oil with filter and i found few really tiny piece of metal (few was ferous metal and few maybe aluminium) and also oil had somethink like metallic touch. Is it really rod knock or it could be piston slap and is normal to hear that? I am ready to disassembly the bottom of engine and check the condition, but I don't want to interfere unnecessarily to rod bearings.
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10-24-2025, 03:57 AM	#2
Phil325i Brigadier General 688 Rep 3,288 Posts Drives: E92 325i MSport Coupe Join Date: Apr 2012 Location: UK South East iTrader: (1) Garage List 2009 BMW 325i Coupe [6.00]	Could it be chain rattle? Have you thought about replacing the timing chain tensioner? I replaced mine at 125,000 as preventive maintenance. It's an easy DIY job... __________________ E92 pre-LCI 325i - Ohlins R&T; H&R spacers; M3 strut brace; Swift thrust sheets; 3 x chassis braces; diff brace; N53 V-brace with cross bar; 034 subframe inserts; BMS clutch stop; BMS CDV; RE g/box mounts; Delrin shift bushes; Saikoumichi OCC; Cyba scoops; BMW Perf Exhaust; HEL s/steel brake hoses; M3 rear spoiler; Recaro Sportster CSs; M3 white dash LEDs; LED Angels; LED side repeaters; BMW Perf black grille; CSL reps; SSDD carbon diffuser; Monster Wrap black roof/clear front
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10-24-2025, 07:15 AM	#3
Jerremy175 Registered 0 Rep 3 Posts Drives: BMW E92, N53B30 Join Date: Oct 2025 Location: Czech iTrader: (0)	I already replace whole timing kit together with oil kit. Tensioner is new OEM.
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10-24-2025, 07:17 AM	#4
Jerremy175 Registered 0 Rep 3 Posts Drives: BMW E92, N53B30 Join Date: Oct 2025 Location: Czech iTrader: (0)	Is it possible that new OEM tensioner is also bad and makes same noise as older one?
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