VACUUM LEAK TROUBLE

Bmwtvboy · #1 12-03-2013, 02:08 PM

X5,3.0,01,auto,178K,
The other day I posted engine/vehicle vibration problem in Drive mode foot on the brake. Tested for motor-mounts and they are fine. Turns out its a vacuum leak, found a hole in my rubber bellows at the throttle body intake. I am wondering where else to look for leaks? How does one know if the intake manifold gaskets are shot? I see someone mentioned Disa valve gasket, I fixed the disa sometime ago but don't remember changing the manifold gasket - disa intake connection. Any hoses in-particular that are prone to failure?
Changed over the CCV a couple of years ago and all was fine. This is very recent, about 250 miles ago it started seriously vibrating. Can prolonged vibration damage other engine components?

Thanks for help..

Sponsored Links

TwinTurboGTR · #2 12-03-2013, 11:42 PM

Well lets step back here. A lot of the stuff you said you checked was from a while ago, so I recommend you start fresh. If it has been over 100K since those parts have been refreshed, it may be time for an overhaul. You doing a DISA valve 2 years ago, could be bad... you just don't know.

So to find additional vacuum leaks, you can use carb cleaner to locate them. Spray on a cold start engine because you are spraying flammable stuff. So spray around vacuum hoses, intake manifold, CCV, just focus around the motor and listen for idle change.

As for the prolonged vibration causing other damage, it all depends.

racingbmwm3 · #3 12-04-2013, 02:05 PM

I don't see the intake manifold gaskets going bad on their own. Usually it would happen if you removed the intake manifold and didn't replace the gaskets with new ones when you put it back together. If you did do that, then that's a likely suspect.
You have a couple vacuum hoses under the intake manifold that can go bad, especially due to oil contamination. There is also the vacuum hose that goes from the secondary air valve around the back of the head, that gets hard and brittle from the heat. And, your vent pipe from the valve cover to the CCV. Also the CCV hoses.
178k, I'd probably just buy a few meters of the vacuum lines and replace all of it. And your CCV is probably worth inspecting/cleaning if you don't mind a PITA job of doing that...

Bmwtvboy · #4 12-12-2013, 03:10 AM

All great points. I did change out the CCV about a year ago. It turns out I have a pinky finger thick whole in the small branch off the intake rubber tube to the throttle body and ICV. Thing is, how do I know if my ICV is still good. Is there an ohm test or other test to do before putting it all back together.
Thanks

racingbmwm3 · #5 12-12-2013, 01:20 PM

There should be an ohm test or voltage drop test you could run on the ICV, not sure where to find those values though.
I'd replace all the hoses and see how it runs after a day or two of driving, it will take a little while for the adaptations to adjust to the new air parameters. Unless you have access to a computer with the BMW software to allow you to manually reset the adaptations.
If its still idling weird after the adaptations are corrected, then I'd look at other causes.
Plus, if you fix a whole bunch of related things at the same time, you'll never know what symptom each thing was causing.

upallnight · #6 12-12-2013, 02:23 PM

The ICV should rattle when you shake it. If it doesn't you will need to clean it out.

Bmwtvboy · #7 01-07-2014, 06:57 PM

Great information as usual. Thank you. Engine idle seems to be fine since fixing the intake tube. ICV is solid. Getting great MPG's and very smooth acceleration. However, this darn vibration is still present. Strange thing; it doesn't vibrate in Park or Neutral and it seems to vibrate the drivers side door and steering wheel the most, but the vibration decreases in the center console and passenger door area is fine. Could it be something with the front drive shaft? Bearing?
Thanks.

bcredliner · #8 01-07-2014, 07:11 PM

When you say it vibrates in drive and I assume reverse. Is that when you are sitting still or moving?

Bmwtvboy · #9 01-22-2014, 03:53 PM

Sorry for the delay. My mechanic believes it's the motor mounts causing the vibration in drive with foot on the brake. Checked all drive train parts underneath and he stated they were solid and fine. With 180K miles and the last 7years hanging in OR with little snow experience or foul weather issues this x has dated nicely. I have to find a tutorial on motor replacement. BTW, spayed carb cleaner after the intake tube replacement and didn't notice any change in idle.

bcredliner · #10 01-22-2014, 07:33 PM

Quote:

Originally Posted by Bmwtvboy

Sorry for the delay. My mechanic believes it's the motor mounts causing the vibration in drive with foot on the brake. Checked all drive train parts underneath and he stated they were solid and fine. With 180K miles and the last 7years hanging in OR with little snow experience or foul weather issues this x has dated nicely. I have to find a tutorial on motor replacement. BTW, spayed carb cleaner after the intake tube replacement and didn't notice any change in idle.

An easy motor mount check--block front wheels, apply hand brake, hold the brake while in drive and with the hood up. Run the RPMs to 2000-2500, not more than you can keep it from moving and have someone stand beside your X where they can watch the engine. Do this outside with nothing to hit. If you are uncomfortable with the transmission in gear you can try with the engine in neutral but it is not as easy to see. If motor mounts are bad the engine will move an excessive amount. If the driver side is bad the engine will rise and if the passenger side the engine will drop down.

Sponsored Links