Dumb Question Thread - No Flaming Allowed

[newton22]

Can someone link me to a page or video that shows exactly how the S54 VANOS works? I'm trying to understand why the exhaust hub has tabs but the intake side doesn't.

[Cubieman]

Smoke testing for vacuum leak. Is there a decent low cost tool/DIY setup for this?

I made one from a pickle jar/soldering iron/sock/baby oil and bike pump later replaced by a airbrush pump I already had. It worked pretty well actually. There is a YouTube on it.

[maupineda]

Amazon, I got one for like 90 bucks last year.

[Nate047]

Smoke testing for vacuum leak. Is there a decent low cost tool/DIY setup for this?

[CrisSilberGrau]

Slideways heinzboehmer Update:

I managed to scan the car last night with no success. No codes came up. I did this after a fresh oil change. For reference, I keep the oil level always at max on the OEM M3 non CSL dip stick. I do have to say that after prolonged hard driving the engine does seem to either burn a bit of oil or have some escape (in the aforementioned vanos line/pressure accumulator area). In the past the yellow light would come on, I'd measure the oil level on lever ground and always found it to be at or slightly below mid. I would complete to max level and the light would then not come on in subsequent drives, until such time enough oil was used/burnt (regardless it would be a while).

That's not the case anymore, I can complete to max oil level, in the next drive the oil light would come on unless parked on level ground.

As for issue 2. juddering, still present but more muted after fixing the bottom idle control bung on the turner CSL but still noticeable. No Codes again.

[heinzboehmer]

1. CSL software seems to be more sensitive to oil level. When the oil is up to temp, it usually wants the level at 1/2 from max to max. If it's at 1/4 to a 1/2, it might throw the yellow oil light on slopes. The sensor is not bad until a code pops up for the oil level sensor malfunction or you will see the oil temp gauge fall to cold. It will not trigger a CEL, so you have to scan for this.

It's not exactly that it's more sensitive. On the CSL, both the physical dipstick and the DME are expecting more oil in the pan. Looks like 4mm higher oil level on the sensor based on my notes.

Edit: Found the thread with pics of the dipstick difference: https://nam3forum.com/forums/forum/s...ator#post97267

[Slideways]

Before I post in the main forum I have two issues.

1. Yellow oil light whenever the car is on an incline with the nose/front at the lowest point. Inclines are not severe, think driveway. There oil sweat at the bottom of the vanos line, I think also around the vanos pressure accumulator. Is this still an oil level sensor issue? Since I have not touched it I assume its original to the car @159k miles now.

2. I've notice a hesitation around 3k rpm. Either when keeping steady throttle application on the hwy in 6th (any gear really) then applying throttle gently theres a judder. In the past it has resulted in the EML light going on and limp mode condition. It would clear itself after a prolonged stop start. I have since found the idle control line hose bung to the Turner airbox was detached, letting in air past the CSL air filter. I have since fixed this. I can still sense a slight hesitation/judder at times. I have not run codes on the dme. Is this a symptom of fueling ie. injectors (OEM rebuilt in 2023), or the fuel pump?

1. CSL software seems to be more sensitive to oil level. When the oil is up to temp, it usually wants the level at 1/2 from max to max. If it's at 1/4 to a 1/2, it might throw the yellow oil light on slopes. The sensor is not bad until a code pops up for the oil level sensor malfunction or you will see the oil temp gauge fall to cold. It will not trigger a CEL, so you have to scan for this.

2. Check the DME for codes and go from there. At that mileage, if you have a slightly blown headgasket, it might not throw a misfire code and the car can drive fine. You want to do a compression test with ALL the spark plugs out. If it passes a compression test, then check the fuel pump as that usually does not throw a code when it is on its way out.

[CrisSilberGrau]

Before I post in the main forum I have two issues.

1. Yellow oil light whenever the car is on an incline with the nose/front at the lowest point. Inclines are not severe, think driveway. There oil sweat at the bottom of the vanos line, I think also around the vanos pressure accumulator. Is this still an oil level sensor issue? Since I have not touched it I assume its original to the car @159k miles now.

2. I've notice a hesitation around 3k rpm. Either when keeping steady throttle application on the hwy in 6th (any gear really) then applying throttle gently theres a judder. In the past it has resulted in the EML light going on and limp mode condition. It would clear itself after a prolonged stop start. I have since found the idle control line hose bung to the Turner airbox was detached, letting in air past the CSL air filter. I have since fixed this. I can still sense a slight hesitation/judder at times. I have not run codes on the dme. Is this a symptom of fueling ie. injectors (OEM rebuilt in 2023), or the fuel pump?

[PSUEng]

I just had my entire front suspension refreshed and am wondering, do used lower control arms (with torn boots) have any value or should I just scrap them (I hate just throw stuff out, maybe someone can use them?)? I also have original FCABS and I'm torn between having bushings pressed in and keep them back as spares, or sell/scrap those too as entire replacements are seemingly (at least for now) available (and I completely replaced them during the refresh).

[jayjaya29]

I hate to even make a post like this, but is there a generic door panel clip that actually holds properly and long term? I bought some on Amazon and I swear I have broken more than have held, trying to put my interior back together.

https://angry-ass.com/product-organizer/p/door-panel-pins-and-isolation-pads

[Nate047]

Yea that's what I mean, there would be no real noticeable flex in this particular example.

[jayjaya29]

There is flex in wheel bearings, uprights, etc but it wont move that much. I run a business card's clearance between front spring perch and tire, and there are never any marks on my tires (although the paint has rubbed off the perch and spring itself, so there is some movement).

[PSUEng]

Was chatting with a guy about wheel fitment, he said his wheels touched the suspension only under load while curbing. That struck me as odd and he said “front wheel hubs do have flexibility in them, right now the clearance is so close that when the wheel hub flexes a millimeter or two it touches” and I was just curious if that sounds right to you guys or not. My assumption has always been that all of that stuff moves in relation to itself and it shouldn’t have flex or dynamic changes relating to how close the wheel is to the suspension.

Hmmm. How would a wheel hub "flex"? The assembly moves in XYZ based on what is allowing it to move (ball joints, linkages, etc.). What is "flexing" I'd like to better understand. Unless something is loose, or damaged, or out of tolerance, I can't imagine what that means. In other words, I agree with your conclusion.

[Nate047]

Was chatting with a guy about wheel fitment, he said his wheels touched the suspension only under load while curbing. That struck me as odd and he said “front wheel hubs do have flexibility in them, right now the clearance is so close that when the wheel hub flexes a millimeter or two it touches” and I was just curious if that sounds right to you guys or not. My assumption has always been that all of that stuff moves in relation to itself and it shouldn’t have flex or dynamic changes relating to how close the wheel is to the suspension.

[Tbonem3]

51248391066

This is the little rubber cap for the trunk hinges. Maybe it would work? I don't know the size difference.