[busted323i]

Hey all, started up my '06 323i today and was greeted by a wonderful knocking sound

https://youtube.com/shorts/RzlkwxcW7rk?feature=share

The frequency of the knocking went up with revs. Last time I checked the oil level (last start up) it was full. It sat outside in -20C weather last night. Also at 1/4 tank gas.

Any ideas what it could be?

Also blower motor went out recently, if that matters

[neilvan]

Sounds like noisy lifters; the earlier N52 engines were famous for it.

Better synthetic and more frequent oil changes will help (if you arn't already) but it should go away once it warms up and goes thru some rpm's

[busted323i]

Originally Posted by neilvan

Sounds like noisy lifters; the earlier N52 engines were famous for it.

Better synthetic and more frequent oil changes will help (if you arn't already) but it should go away once it warms up and goes thru some rpm's

That's lifter tick?! Never been that loud for me before, but no CEL I guess

[Suvorovo]

06 N52, no lifter tick my car had oil changes every 5k since new. In additional to oil changes, try driving at a steady 3k-4k RPM for 10-15 minutes straight. I heard that will help build sufficient oil pressure to the lifters. Not sure for how long this will help, if at all, but it doesn't cost anything. Let me know if this solves the problem during the next cold start up. I'm interested myself.

[busted323i]

Update time:

Drove around a bit longer this evening (30 min) and the tick was gone.

(My commute is 15 min lol)

So I guess it was just some crazy lifter tick

Plus my blower motor is now working lmao didn't do anything different.

[whyzee125]

That title scared me but definitely not knock, agreed, sounds like lifter tick. My old M54 ZHP used to do a similar noise sometimes. Glad it stopped regardless!

[PhaseP]

Originally Posted by busted323i

(My commute is 15 min lol)

If the 2.5 liter N52 is anything like the 3.0 liter N52, and the ticking or tapping noise is louder on the top back exhaust side of the engine, then that is your problem: short drives. Get used to that ticking noise. Mine had been ticking now and then since brand new, 16 years, no ill effects.

Plus my blower motor is now working lmao didn't do anything different.

Most likely the blower motor shaft developed rust at the top and sometimes binds within its bearing. Common issue, easy to replace. You can clean it up and put some oil or grease, but sooner or later it will stop again. There is a popular good old thread on how to replace the blower motor in this forum.


Ah, the sticky lifters making ticking noise has its own sticky thread too, thousands of pages long. Like the lifters, that thread is noisy.

[k90]

My engine started ticking just like in the video right after retrofitting cruise.
The cruise maintains speed outside the torque band effortlessly compared to driving with pedal - so I upshift more.

[Suvorovo]

Originally Posted by PhaseP

If the 2.5 liter N52 is anything like the 3.0 liter N52, and the ticking or tapping noise is louder on the top back exhaust side of the engine, then that is your problem: short drives. Get used to that ticking noise. Mine had been ticking now and then since brand new, 16 years, no ill effects.

Most likely the blower motor shaft developed rust at the top and sometimes binds within its bearing. Common issue, easy to replace. You can clean it up and put some oil or grease, but sooner or later it will stop again. There is a popular good old thread on how to replace the blower motor in this forum.


Ah, the sticky lifters making ticking noise has its own sticky thread too, thousands of pages long. Like the lifters, that thread is noisy.

Does running the blower motor regularly prevent the rust from building up and binding? My car had recall for blower motor wiring, not sure if the entire blower motor was replaced.

I always run my fan at 1 or 2.

[Pittz1]

Happens to me only when I take short trips around town. 216k miles and the motor is as strong as new. These n52's are amazing.

[k90]

Originally Posted by Suvorovo

Does running the blower motor regularly prevent the rust from building up and binding? My car had recall for blower motor wiring, not sure if the entire blower motor was replaced.

I always run my fan at 1 or 2.

Idk about recalls but mine had some wiring work done to it. The big brown and red wires had glue heatshrinks on top of them as I assume one end of wires had been changed and connected to original wire. Didn't investigate further, but for sure those were blower related wires.

[Suvorovo]

Listened to your video OP. Classic lifter tick. Try to drive your car harder (after proper warmup) for longer. I usually aim for 3k RPM. Shift up at 4k for regular driving. 3k RPM going 70-80 in 5th on the Highway, rarely use 6th. Seems to be perfect balance for torque vs MPG. ~2k-2.5k for the first 10 mins or so after cold start. Automatics might shift at lower RPMs, no idea.

Once lifter tick starts, it’s hard to get rid of, but trying is free.

Anyone have an idea if lifter tick is more common on automatics than manuals? You can rev out regularly on a manual.

[PhaseP]

Originally Posted by Suvorovo

Does running the blower motor regularly prevent the rust from building up and binding? My car had recall for blower motor wiring, not sure if the entire blower motor was replaced.

I always run my fan at 1 or 2.

After I replaced my first fan due to sticking and stopping, I always ran the fan at minimum speed, never turned it off, with the same idea you wrote.
The lowest speed is so low and fan is so quiet that I don't even hear it, so doesn't bother me.
I would say that worked for me. I didn't need to replace the fan since, don't even remember how long it was ago, it could have been 10 years.

Only this year it stopped working during hot summer days but then coming back up running again. It could have been the fan is old now, or something else is going on with the AC system deciding not to turn it on due to some heat sensor giving wrong readings, or which I suspect more I had windshield replaced due to a crack and the bottom lip seal on the glass is not placed correctly letting some rain water come down on to where the fan is.

[PhaseP]

Originally Posted by k90

Idk about recalls but mine had some wiring work done to it. The big brown and red wires had glue heatshrinks on top of them as I assume one end of wires had been changed and connected to original wire. Didn't investigate further, but for sure those were blower related wires.

That is the recall on blower motor wiring. In worse case scenarios the wires would catch on fire, so they recalled and did some rewiring.
They would not change the blower motor as part of that recall, unless maybe the motor found to be not functioning due to the heating wire connection on it.

[busted323i]

Yea so the blower motor has been working 95% of the time, sometimes during driving the blower will turn off and back on again.
Probably rusty/binding, so I'll have to oil it up (possibly when the weather is above -40 lmao)

[k90]

Originally Posted by busted323i

Yea so the blower motor has been working 95% of the time, sometimes during driving the blower will turn off and back on again.
Probably rusty/binding, so I'll have to oil it up (possibly when the weather is above -40 lmao)

I have had same thing happening in cold weather. Bearings would need a drop of mineral oil, but I don't think it's what is causings sudden halts of blower. Maybe brushes are gone? Or something related to battery state? Does blower control care about battery state?
Blower motor looks like it's sealed in plastics. Easy to remove?

For the valve lifter tick I'm planning to add RVS at end of oil life to experiment if it will deal with the sound for good. At least in motorcycle the shifter feel changed(more accurate/short) after RVS. I think.