Squeaking belt? I've tried lots of suggestions from Forums.

[T_EV]

Been trying for weeks to get this noise to stop and it keeps coming back. I've read threads here and have done the following within the last 2,000 or so miles:

Brand new OEM alternator
Brand new OEM Serpentine Belt
Brand new OEM Tension Pulley
Brand new OEM Deflection (3 IIRC?) pulleys
Replaced OFHG
Removed belt and deep cleaned all pulleys and belt with a brush and water

When you check out the below videos some things to note:
1. The sound gets worse at higher RPM's, is almost nonexistent or slower at idle
2. When I take off the belt and clean it the noise goes away; most recent scenario was yesterday, I took the belt off and cleaned everything in the morning, put the belt back on the car, drove 40 miles to visit family with little to no squeak, drove back 40 miles and once I'm home I took the below videos. It was very loud at this point.
3. When I replaced the OFHG a month ago, I replaced the serpentine belt and pulleys at the same time; after replacing the OFHG I cleaned all oil residue from the leak. Yesterday when cleaning the belt, there was no evidence of a new leak.

What I think could possibly be wrong:

1. I was sold a bad pulley or tensioner from ECS Tuning
2. There is some way that oil or some fluid is getting on the belt that I am oblivious to, the only pulley that I am not able to get to to clean 100% is the Crank pulley which doesn't freely spin at the very bottom of the engine.
3. Radiator fan squeaking?

Also, ignore the CEL in the second video, it is a wheel speed sensor that is on its way to me to replace this week as well. Man aren't these fun little cars !

[HyeWarrior]

Its a crack in your valve cover, willing to bet money on it

[chris_flies]

Originally Posted by HyeWarrior

Its a crack in your valve cover, willing to bet money on it

That would be a reasonable diagnosis!

OP, I'd also make sure all of your OFH bolts are tightened correctly, the ones holding the oil cooler adapter into my new housing weren't tightened when I got it and it was dripping oil onto the belt, which then flung oil everywhere in the engine bay. Much fun to clean...

[T_EV]

Originally Posted by HyeWarrior

Its a crack in your valve cover, willing to bet money on it

Is this a common issue with the N55's? You sound like you've gone through this before. Do you recommend replacing just the gaskets for 50$ or the entire Valve cover for ~ 500$ diy?

It would help if I could see an active leak or if there is a way to detect an active leak. I cleaned everything up really good last time I had it all apart and there is no oil residue anywhere.

Also, finding a few DIY videos on the N54 job which looks very intimidating, but none on an N55. Any DIY vids out there for the N55?

[HyeWarrior]

Originally Posted by T_EV

Is this a common issue with the N55's? You sound like you've gone through this before. Do you recommend replacing just the gaskets for 50$ or the entire Valve cover for ~ 500$ diy?

It would help if I could see an active leak or if there is a way to detect an active leak. I cleaned everything up really good last time I had it all apart and there is no oil residue anywhere.

Also, finding a few DIY videos on the N54 job which looks very intimidating, but none on an N55. Any DIY vids out there for the N55?

Not sure if its common, but from what you've described, I had nearly the same exact symptoms and noises based on your videos. At the time, I was utilizing a local mechanic. He misdiagnosed by replacing my pulleys and even my alternator before figuring out the crack in the valve cover. If i remember correctly, a smoke pressure test didn't even help. He came across this thread:

http://www.e90post.com/forums/showthread.php?t=1197666

Sure enough, solved the issue. I don't think it looks like that difficult of a DIY. Only reason I didn't tackle the project is because he barely charged me on labor due to the misdiagnoses. From what he said, luckily my seals were still in good shape.

Hope that helps.

[T_EV]

Originally Posted by HyeWarrior

Not sure if its common, but from what you've described, I had nearly the same exact symptoms and noises based on your videos. At the time, I was utilizing a local mechanic. He misdiagnosed by replacing my pulleys and even my alternator before figuring out the crack in the valve cover. If i remember correctly, a smoke pressure test didn't even help. He came across this thread:

http://www.e90post.com/forums/showthread.php?t=1197666

Sure enough, solved the issue. I don't think it looks like that difficult of a DIY. Only reason I didn't tackle the project is because he barely charged me on labor due to the misdiagnoses. From what he said, luckily my seals were still in good shape.

Hope that helps.

Hit it right on the head, thanks!

From the above thread:

'If you have any reason to suspect PCV system malfunction, first open the oil cap to see if the problem (e.g. main seal noise) immediately subsides'

Tried this last night, noise immediately stopped, tightened/sealed the oil cover cap and the noise started again. Glad to know what the problem is.

I assume that at this point in time I just need to bite the bullet and
1. buy this: https://www.ecstuning.com/b-genuine-...r/11127570292/
2. Do the plugs/ignition coils while I'm at it. (is this necessary?)
3. Drive away into the sunset until and have no more problems for another 100k miles?

Am I missing anything?

Also, am I safe to drive for a few weeks? Funds are low after the 1200$ starter job from a week ago.

[HyeWarrior]

Originally Posted by T_EV

Hit it right on the head, thanks!

From the above thread:

'If you have any reason to suspect PCV system malfunction, first open the oil cap to see if the problem (e.g. main seal noise) immediately subsides'

Tried this last night, noise immediately stopped, tightened/sealed the oil cover cap and the noise started again. Glad to know what the problem is.

I assume that at this point in time I just need to bite the bullet and
1. buy this: https://www.ecstuning.com/b-genuine-...r/11127570292/
2. Do the plugs/ignition coils while I'm at it. (is this necessary?)
3. Drive away into the sunset until and have no more problems for another 100k miles?

Am I missing anything?

Also, am I safe to drive for a few weeks? Funds are low after the 1200$ starter job from a week ago.

When did the noise start? How many miles are you at? Do you have a tune? Have you ever replaced the plugs?

For what it’s worth, I drove with that noise for almost a month before I had it taken care of.

[T_EV]

Originally Posted by HyeWarrior

When did the noise start? How many miles are you at? Do you have a tune? Have you ever replaced the plugs?

For what it’s worth, I drove with that noise for almost a month before I had it taken care of.

I have only had the car for 2 months and purchased at 71,000 miles.

Currently:
Noise started a week ago
72,200 miles
No tune
Round trip to work each day: Back roads less than 8 miles round trip. I don't get above 50 mph.
I've never replaced plugs and have no way of knowing if they've been replaced (other than taking them out and looking) I plan on 100% doing the plugs but are the ignition coils necessary to replace. I'm going to do it if I find oil that has made its way past the seal but if they look fine are they a wear item that needs to be preventatively replaced or are they fine for the life?

[HyeWarrior]

Can’t speak for the ignition coils. I’m at 76k and had the plugs replaced when I bought it at 50k. I’d only do the plugs if I were you.

I also had my starter replaced not long ago like yourself. These cars can be a pain, but they’re great when they work

[chris_flies]

Originally Posted by T_EV

...I'm going to do it if I find oil that has made its way past the seal but if they look fine are they a wear item that needs to be preventatively replaced or are they fine for the life?...

They wear, especially when you have bad plugs. The DME (ECU) makes adjustments when spark plugs aren't 100%, which usually consists of working the coils harder, compensating for worn plugs. Very cool thought, but it masks bad plugs, and gives you much more to replace when something does go kaput...

[Matticus91]

Didn't have the time to read the whole thread so apologies if someone mentioned this already - sounds like it could be the power steering pump, have you tried checking it/adding fluid?

Start with the cheap stuff and work your way up....

[T_EV]

Originally Posted by chris_flies

They wear, especially when you have bad plugs. The DME (ECU) makes adjustments when spark plugs aren't 100%, which usually consists of working the coils harder, compensating for worn plugs. Very cool thought, but it masks bad plugs, and gives you much more to replace when something does go kaput...

Yep, I saw this somewhere in all my reading I've been doing. I purchased the car at 72k and have no idea if the plugs have ever been changed, although the carfax shows detailed dealer maintenance. Plan is to order the plugs, coils, and Valve Cover Gasket. When I get down in there, check the plugs and if they look terrible, I'm going to replace the coils at the same time, if the plugs look like they've been replaced, I'll just put the new plugs in and return the coils (or just keep them for shelf stock).

[T_EV]

Originally Posted by Matticus91

Didn't have the time to read the whole thread so apologies if someone mentioned this already - sounds like it could be the power steering pump, have you tried checking it/adding fluid?

Start with the cheap stuff and work your way up....

This is the first time I've seen this come up. I was 100% sure it was the Valve Cover Gasket or more specifically the PVC valve which is built into the VCG because when I take the oil cap off which depressurizes the system, the noise immediately quits, seal the oil cap back on... Noise starts again. I will, however, check the PS fluid tonight JUST in-case, thanks for the suggestion!

[Matticus91]

Originally Posted by T_EV

This is the first time I've seen this come up. I was 100% sure it was the Valve Cover Gasket or more specifically the PVC valve which is built into the VCG because when I take the oil cap off which depressurizes the system, the noise immediately quits, seal the oil cap back on... Noise starts again. I will, however, check the PS fluid tonight JUST in-case, thanks for the suggestion!

Got it, and no problem!

[chris_flies]

Originally Posted by T_EV

Yep, I saw this somewhere in all my reading I've been doing. I purchased the car at 72k and have no idea if the plugs have ever been changed, although the carfax shows detailed dealer maintenance. Plan is to order the plugs, coils, and Valve Cover Gasket. When I get down in there, check the plugs and if they look terrible, I'm going to replace the coils at the same time, if the plugs look like they've been replaced, I'll just put the new plugs in and return the coils (or just keep them for shelf stock).

If they have a light tan color on the tip, then they are functioning correctly, BTW. I was very concerned when mine went perfectly clean, but I did my research and found that it's normal...

[T_EV]

*** UPDATE ***
Took it to the shop (local Indy been there 25+ years, 4,000 reviews on Google, 4.9 stars) for a second opinion before I tore the car apart to replace the Valve Cover. Tells me it's the AC Compressor and he's 100% positive. Quotes me $2,200 to fix. He only uses OEM parts in order to provide a 2 year warranty on parts & labor. OEM AC Compressor is $1,500.

So going from here, I have three options:

1. Pay $2,200 bringing my total repair costs in the last 3 weeks to $3,500. I have the money but would have to dip into savings and my wife would probably kill me in my sleep.
2. DIY. Buy an aftermarket AC Compressor (link below) and get someone to professionally remove the freon, and then re charge after the work is done: Cost: $350 for the part, $150 for AC System removal/recharge. Save $1,700.
3. Buy the Aftermarket Denso unit and get the shop to install it. He said he would do it but couldn't warranty the labor. Cost: $1,200; Save $1,000.

I'm leaning towards #2 because the job is pretty easy from what I can tell, especially with getting the freon or refrigerant (whatever the correct term is) removed at a shop. Does anyone have any opinions about aftermarket options like the link below ($350) vs OEM that fails at 70k miles ($1,500)?

I've seen the DIY on the threads but it's an N54. I'm pretty mechanically inclined, I was going to DIY the valve cover job and was confident in my abilities. Another note, I've seen something about oil in the AC compressor? Something about checking oil levels before and replacing oil when you put a new AC Compressor in? Any ideas?

https://www.autozone.com/cooling-hea...19_153838_3513

[BimmerAg]

Based on your previous test where the noise stopped when you removed the oil cap, I highly doubt that the AC compressor is at fault. If the compressor was failing, why would the noise stop when you remove the oil cap? If you really want to be sure, I'd try to get a third opinion.

[chris_flies]

About the oil in the compressor:

As far as I know, it's not necessary, or even possible, to check the levels in our cars. I do know that modern refrigerant, sold everywhere, contains lubricants, anti-corrosion agents, and conditioners inside them to keep your A/C system maintained and healthy.

I agree with BimmerAg , though. After your oil cap test, I seriously doubt it's your A/C compressor that's at-fault. Bad A/C compressors either lock up entirely and cause belts to melt, or make some other kinds of God-awful sounds that you'd definitely know. Plus, the A/C wouldn't work, and you'd notice that...

[MightyMouseTech]

If the noise is coming from the bottom front of the engine, it could also be the front main seal. Our N55 engines are run at a vacuum inside the engine. When you remove the oil filler cap, you are actually pressurising the inside of the engine to atmospheric pressure. Could be air leaking past the front main seal while under vacuum.

Run the engine with and without the belt. If the noise is there without the belt, you know it is not the A/C compressor.

[Gizmo135i]

If the noise goes away when you remove the cap then it is most likely the valve cover. When the vent valve goes bad it can create excess vacuum in the engine, which in turn causes air to leak in through the front or rear main seal.

The proper way to diagnose would be to check the crankcase vacuum w/ a gauge via a special oil cap tool Bmw makes that has a fitting for a gauge. That’s kind of unecessary since it’s kind of obvious.

Is the cap hard to get off with the engine running when the noise is happening?

[T_EV]

Originally Posted by MightyMouseTech

If the noise is coming from the bottom front of the engine, it could also be the front main seal. Our N55 engines are run at a vacuum inside the engine. When you remove the oil filler cap, you are actually pressurising the inside of the engine to atmospheric pressure. Could be air leaking past the front main seal while under vacuum.

Run the engine with and without the belt. If the noise is there without the belt, you know it is not the A/C compressor.

I assume it's ok to run the engine without belts for a simple test? This would 100% prove it's the ac compressor v. something else.

Originally Posted by chris_flies

About the oil in the compressor:

As far as I know, it's not necessary, or even possible, to check the levels in our cars. I do know that modern refrigerant, sold everywhere, contains lubricants, anti-corrosion agents, and conditioners inside them to keep your A/C system maintained and healthy.

I agree with BimmerAg , though. After your oil cap test, I seriously doubt it's your A/C compressor that's at-fault. Bad A/C compressors either lock up entirely and cause belts to melt, or make some other kinds of God-awful sounds that you'd definitely know. Plus, the A/C wouldn't work, and you'd notice that...

Yeah I was/am skeptical. There are no signs of the ac going bad. I'm still getting cold as ice ac from the vents. It could all be in my head but I feel like if I'm running the ac the squealing is less noticeable. Could just be me imagining things. Not to mention the lack of info on bad ac compressors on the N55 vs. the wealth of info on valve cover gaskets.

Originally Posted by Gizmo135i

If the noise goes away when you remove the cap then it is most likely the valve cover. When the vent valve goes bad it can create excess vacuum in the engine, which in turn causes air to leak in through the front or rear main seal.

The proper way to diagnose would be to check the crankcase vacuum w/ a gauge via a special oil cap tool Bmw makes that has a fitting for a gauge. That’s kind of unecessary since it’s kind of obvious.

Is the cap hard to get off with the engine running when the noise is happening?

The cap is hard to get off when the engine is running, it's 'sucked' down noticeably. I'm going to retest everything again this afternoon by taking the oil cap off and seeing if that makes the noise go away, and by taking the belt off to see if I can replicate the noise.

[HyeWarrior]

I remember the AC masking the noise as well, or at least making me feel like it’s masked.

I still think it’s the valve cover!