Engine Bay Sounds

[Oli77]

The other day I leave the car running and step our to get my sun glasses in the house and as I pass by the front of the car I hear a funky sound.

Not the hiss of the air, not the valves clicking away but a deeper "piston-like" noise. I open the hood and hear pistons clunking around.

So I search and I search, and I find many youtube videos with microphones inside M3 engine bays while driving, or people describing countless VANOS, or DISA sounds or air leaking sounds or clicking sounds. What I don't find is the noise I am hearing. Mind you, I could be completely wrong about this and all is normal.

I thought I could start a thread where we place a short video of our cars idling. This could give us a baseline from which to determine the presence normal, abnormal, and of course "funky" noises, for diagnosis purposes.

Of course it would be best if more of us upload a video or sound file so we have more data to increase our knowledge base.

Here is mine, noise is coming from the left side of engine (video). I would appreciate any comments about that piston-slap-like noise. Happens hot or cold, this is a ZSP, manual, 95K miles, no codes, power is good, new oil (0W40; Mobil 1; synthetic; Longlife 01 BMW approved) about 1500 miles ago.



https://dl.dropboxusercontent.com/u/27597541/VIDEO0029.mp4

[TheFinanceGuy]

That is an odd noise.

Here is mine at warm idle


http://vimeo.com/101104569

[328ioc]

Definitely sounds like its at the font of the engine.

My guesses are VANOS, water pump or pully/idler related.

I think if it was actually something with the pistons you would notice some more issues.

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[rguti153]

Mmmmmm

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[TristanHunter]

Sounds like a bearing to me. +1 for WP or a pulley

[328ioc]

Let me add that my reasoning for VANOS is because it kinda sound like what a VANOS sounds like when listened too through a stethoscope just super loud.

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[rguti153]

Not good

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[328ioc]

Its probably still a WP or pulley but always worth giving the VANOS a look.

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[rguti153]

A wp ? Water pump ?

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[328ioc]

Yeah. Water pump. Lol

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[rguti153]

Oh k lol gotta ask shiaaatt

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[Oli77]

Thanks all for the responses. WP was replaced OEM about 3 years ago and has about 25K miles on it.

I can feel the sound over the center of the engine (all over the valve cover) not more so towards the VANOS. Definitely nothing over to the intake side.

I placed a wood-stethoscope over the VCG bolts and can hear metal sounds transfer. That sound is not louder toward the VANOS (could still be it though).

I would love this to be the idler pulley but it sounds like its throughout the engine more so than the front.

I thought VANOS sound was more like a rattle. Also, would my MPG be bad if VANOS were the culprit?

[328ioc]

The normal audible VANOS sound is a rattle correct.

Hmmmm so maybe an issue with the exhaust can?

How does it run and drive other than the noise?

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[Oli77]

Run and drives and pulls well I think. MPG at 23.7 in city.

Yes maybe cams. But their "timing alignment" is driven by the VANOS correct?

If i increase RMP, obviously sound increases in rhythm.

[WOLFN8TR]

Definitely sounds like its at the font of the engine.

My guesses are VANOS, water pump or pully/idler related.

I think if it was actually something with the pistons you would notice some more issues.

That was my guess as well.

[SoarinZHP]

My guess would be a/c compressor / clutch?

[rguti153]

Why u say ac compressor ? Just wondering

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[Hornung418]

Wow. Thats definitely piston noise. Not a bearing or a vanos rattle.

Oli, pull your MAF Oli and see if the noise goes away.

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[Oli77]

OK. So start it up and then remove maf connection? Or remove maf and start it up?

[Hornung418]

OK. So start it up and then remove maf connection? Or remove maf and start it up?

Either, or. The result should tell you weather or not its a fuel related issue. Sounds like you're knocking. No shadow codes?

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[Oli77]

MAF on or MAF off does not matter, sound persists.

8 pending codes, Misfire, O2 sensor, Fuel, Comp, Catlyst, Evap, Sec Air, O2 Htr.

And then after running without MAF, I got P0102 and P0113

[rguti153]

Injectors

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[Oli77]

I cleared the codes. Will drive a bit tomorrow and see if they come back.

I hope some of these codes were 'leftover' from another car I scanned (not sure).

I will be gone most of the day tomorrow but will be coming back to this thread ASAP as I'm worried. It does sound like top of engine noise.

Bad injector(s) you think would cause this metallic rubbing knocking sound?

Mummy!

[Hornung418]

Don't freak out. Run a bottle of Techron in your next tank and clean out your injectors. It definitely sounds like a misfire to me. And it will clank and creak if its beyond the DMEs ability to correct the knocking.

Scann it tomorow when the codes come back.

Just keep in mind that the O2 related code is telling you that the oxygen sensors are still working. But the O2 heater code worries me.

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[Oli77]

Thanks for those comforting words. I will do that and report back tomorrow. About 3 months ago I did run a third of a bottle of seafoam in the gas tank. It made my idle smoother (no more dip).

[Oli77]

Injectors

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Don't freak out. Run a bottle of Techron in your next tank and clean out your injectors. It definitely sounds like a misfire to me. And it will clank and creak if its beyond the DMEs ability to correct the knocking.

Scann it tomorow when the codes come back.

Just keep in mind that the O2 related code is telling you that the oxygen sensors are still working. But the O2 heater code worries me.

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So your theory sounds right. You think I have weak function on one cylinder or 2 that is causing the engine to sound a bit limpy?

It's weird that I can't feel a loss of power and No upfront codes. The only codes so far are "pending". No dash light.

Drove 4 miles filled up + techron bottle. 4 codes came back, Evap, Catlyst), O2 sensor, O2 htr.

[Hornung418]

Keep monitoring it. Your O2 sensors are a lot cheaper than ours. Think I paid ~$100 for both when I did the 328i sensors.

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[Oli77]

You feel it is OK to drive it normally? or am I risking a disastrous failure?

[Hornung418]

You feel it is OK to drive it normally? or am I risking a disastrous failure?

Doesn't sound too horrible. As long as the engine is running smoothly and not shaking like crazy you should be okay.

Mine was knocking and pinging, the car would shake and the idle was rough. If thats not happening, you will be fine to further process the situation.

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[Dave1027]

How about taking a two foot piece of hose. Put one end to your ear and the other to various spots on the engine to localize the noise.

[Oli77]

^ I did it with a piece of wood and its loud all over the top of the engine. Loudest is over the oil filler cap I'd say.

[Dave1027]

Then maybe valve train noise? What does the underside of the oil cap look like? Any mayo?

[Oli77]

I'll try and find valve train noise videos to compare. No Mayo.

I do hear the noise at VANOS as well but it is louder behind the VANOS, toward middle of engine.

[Oli77]

All valve train noises I find seem to sound like clicks. The sound I have is deeper more like a piston rubbing.

[Oli77]

Yesterday after some more driving and Techron hard at work cleaning my injectors the noise persisted.

Then as I was sitting in front of the car, pulling a Dario, and whispering in its' kidney grills, I heard sounds of pulleys grinding.

So I think an easy thing to do is to take of the belt and see if the idler pulley (that some of you identified above) is indeed the culprit.

This one (http://www.ecstuning.com/BMW-E46-325i-M54_2.5L/Search/SiteSearch/Pulley/ES2575757/) is all I need to change right?

[danewilson77]

Can you do all the pulley's and both belts?

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[Oli77]

I suppose I could. Belts are 2-3 years old, so is water pump.

You are thinking of the tensioner pulley and the same on the AC compressor side?

Just trying to find the noise and thought, if I can remove the belt and spin those pulleys by hand and hear the ball bearings, I'll know what to change then.

I can change those 2 on the alternator side and see (they are at 91K miles right now).

Not sure which tensioner I have (hydraulic or mechanical). I will look at it and then buy the correct tensioner puller as well.

[Hornung418]

If they soon freely without resistance, they are shot. A new pulley will spin and stop in a few revolutions.

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[ELCID86]

If they soon freely without resistance, they are shot. A new pulley will spin and stop in a few revolutions.

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...Spin...
;-)
And a new one won't make a full revolution.


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[Oli77]

Gotcha. I will double check and get both pulleys on the alternator side.

[Oli77]

I bought tensioner pulley and idler pulley. Will replace probably Friday and hope that was it (at 91K miles, its good preventive maintenance, no matter what).

Wish me luck with that dang Fillester screw...

[Hornung418]

Snap a picture with your phone to confirm torx or hex. Thats what I do ;)

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[Oli77]

I already know its a hex. Someone before me didn't and its chew up a bit so I bought a new one.

[Hornung418]

Ahh. Gotcha.

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[Oli77]

Well it took 35 minutes and $65 at ECS tuning to find out that the noise was NOT idler pulley or tensioner pulley!

Sure the originals (I presume) were free flowing and had a little play. Made some noise but could have probably gone more. We'll chuck that one to the Gods of preventive maintenance.

That sucks the big ones. I guess, the AC tensioner could be bad but that noise is up top.

I wonder if I am witnessing the birth of a Vanos sound after all. Thoughts? Help!

[Hornung418]

Have you replaced the seals and piston washers? That sucks that it didn't fix the issue, but at least it's out of the way.

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[Oli77]

Seals and piston washers on what?

[Hornung418]

VANOS!!

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[Oli77]

Afraid you were gonna say that. Sucks cause my VCG is not leaking. I dread that a bit. Maybe I can drive up to Lebanon with a six pack and work on it with a caring gentleman who has done this job before...

Still, it does not sound like the marbles in a can rattling. But hey, my pulleys are smoooooooth man.

[Oli77]

Ding-ding-ding, we have a winner (or several of you above)!

Ran it without the belt, and the noise vanished.

It's the water pump. Has no play or very little, but it sounds metallic and spins really easily by hand.

Question: How much fluid do I loose when I change it? i would guess not much because it is pretty high.

Looking for a DIY . . .an recommendations on parts (stewart, oem, metal impeller) please.

[328ioc]

If not stewart definitely go metal.

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[Oli77]

This is (http://www.oembimmerparts.com/BMW_High_Performance_Water_Pump_By_EMP_Stewart_p/888010330E46.htm?gclid=CjwKEAjwgMieBRCB3bqB94e9lD4 SJABW3sTNeiwlbw4qLA2IttRjXXNVE5RBB83JibmdYQA63ApyK hoCKLLw_wcB) the cheapest Stewart pump I can find.

Dealer wanted $166 for an OEM metal impaler one. So I passed.

Free shipping.

[328ioc]

This is (http://www.oembimmerparts.com/BMW_High_Performance_Water_Pump_By_EMP_Stewart_p/888010330E46.htm?gclid=CjwKEAjwgMieBRCB3bqB94e9lD4 SJABW3sTNeiwlbw4qLA2IttRjXXNVE5RBB83JibmdYQA63ApyK hoCKLLw_wcB) the cheapest Stewart pump I can find.

Dealer wanted $166 for an OEM metal impaler one. So I passed.

Free shipping.

Yeah. They usually have good prices on things and the shipping is fast too.

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[Oli77]

While I wait, I'll be doing the old OBC 19.7. a lot. Today I was still running at 95 degrees Celsius.

Will be interesting to see if the 20% more efficient pump reduces engine temps somewhat.

So to double check, open bleed valve at top, and empty expansion tank from bottom, then remove fan shroud, belt and water pulley.

Remove water pump, lose some coolant (how much comes out at this point?) and replace with new pump.

Close expansion tank at bottom blue screw, fill it with 50/50, turn heater on full heat, start car.

Continue feeling expansion tank with engine running.

Something about raising the front of the car so there is no air in the system?

[328ioc]

Honestly, since you will be in there might as well just drain the whole system and fill with new coolant.

Who knows maybe there are impeller pieces floating around.

Also I would use the BMW Blue Coolant and distilled water versus the store bought 50/50 stuff.

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[Oli77]

I did buy the BMW coolant when I was at the dealer inquiring about the pump.

From where do I drain the entire system?

[328ioc]

Honestly its been two years since I did my cooling system so I can't remember.

But I'll see if I can find the DIY I used.

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[Hornung418]

Ding-ding-ding, we have a winner (or several of you above)!

Ran it without the belt, and the noise vanished.

It's the water pump. Has no play or very little, but it sounds metallic and spins really easily by hand.

Question: How much fluid do I loose when I change it? i would guess not much because it is pretty high.

Looking for a DIY . . .an recommendations on parts (stewart, oem, metal impeller) please.

When I did mine, I went for it with out draining anything. It was fun. I used a trash bag and caught everything that spilled out. Quick and easy.

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[Oli77]

^ like a Boss! I guess you didn't do a coolant refresh.

Might as well do it all the way, the coolant in there is 2-3 years old.

The Pelican website DIY (http://www.pelicanparts.com/BMW/techarticles/BMW-3-Series-E46/32-WATER-Flushing_Your_Coolant/32-WATER-Flushing_Your_Coolant.htm) says to empty from the engine block drain plug as well as the radiator and the expansion tank.

You guys did all 3?

[Hornung418]

I did buy the BMW coolant when I was at the dealer inquiring about the pump.

From where do I drain the entire system?


Honestly its been two years since I did my cooling system so I can't remember.

But I'll see if I can find the DIY I used.

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The block drain plig is located between cylinder 2 and 3. Up under the headers. Use a wide mouth hose to catch the plug and stream of coolant that will spill out.

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[328ioc]

I believe I did all 3 yes.

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[Oli77]

Great! Thanks guys, that will be done soon.

Is it really necessary to replace the washer on the block plug?

[Hornung418]

Great! Thanks guys, that will be done soon.

Is it really necessary to replace the washer on the block plug?

Nah.

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[danewilson77]

Great! Thanks guys, that will be done soon.

Is it really necessary to replace the washer on the block plug?
Depends on what it looks like. Use you judgement.

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[ELCID86]

Great! Thanks guys, that will be done soon.

Is it really necessary to replace the washer on the block plug?

No


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[Oli77]

Well I feel like I partially failed. I only drained about 1.1 gallon through the two blue screws at radiator and expansion tank. Could put my angled driver on the 13mm engine block plug but could not move it. I was stuck between the sway bar and the power steering hoses. So I moved on without emptying the block.

The old coolant was still nice and clean and bluish. I figured that it would be ok. I added a full gallon of the BMW coolant and a quarter of a gallon of distilled water. I guess that means 3/4 of a gallon of the old stuff was left behind.

I drove around. No lights. All good for now. I will add water tomorrow.

The good news and successful component of this story is that the awful engine noise is gone.

[Hornung418]

Yay!!

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[danewilson77]

You'll be fine, but yeah, a large portion is held in the block.

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[Oli77]

Yea, that block bolt won. Wonder if shorter wrench might have worked.

Thanks guys. That awful racket in the engine bay had me worried.

Oh, and if this could help the next one, when you pull the pump with the m6 bolts, at least a quarter of a gallon comes rushing out. Bit of a mess, went over both belts, etc....

Temp last night reached 95 degrees Celsius as before. So the claimed 20 percent flow increase from the Stewart water pump does not affect temperature it seems.

[328ioc]

I guess this is the month for engine noises.

I have developed a high pitched whine that is intermitent. Ordered new idlers last night.

Going to replace them this weekend of they get here in time.


Oli, great job diagnosing it and with the fix!

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[Oli77]

So all in all I ended up adding about 1.5 gallons to the cooling system. Guess this means without taking the 13 mm engine block bolt, I only did ~70% coolant exchange.

Thanks for all the help. And hope its as simple as an idler pulley for you.

Post a video of engine noise so we can beef up this thread maybe.

[328ioc]

So all in all I ended up adding about 1.5 gallons to the cooling system. Guess this means without taking the 13 mm engine block bolt, I only did ~70% coolant exchange.

Thanks for all the help. And hope its as simple as an idler pulley for you.

Post a video of engine noise so we can beef up this thread maybe.

Thanks I figure its that at 110k miles.

I would post a video but it really only happens under load and is very intermitent.

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[Hornung418]

Oh, and if this could help the next one, when you pull the pump with the m6 bolts, at least a quarter of a gallon comes rushing out. Bit of a mess, went over both belts, etc....


Thats why you put a trash bag under the pump to catch the spillage :) save that for next time.

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[Oli77]

^ Lol, I didn't catch that on your first mention of a trash bag. Now I see how a trash bag under the water pump is a great idea.

It's the little things...