After changing the oil on my wifey's mustang today, I started the car and let it sit a while to check for leaks etc. When I shut the car down I heard a gurgling sound and then a rattling sound coming from the passenger side of the engine bay near the firewall. It started a couple seconds after the motor stopped rotating and lasted for about 5 seconds. The motor would stop rotating then a second later the gurgling would start for a second or two. When the gurgling stopped the rattling would start. With a mechanics stethoscope, and my wifey turning the car on & off, I was able to narrow it down. The gurgling is coming from the EGR Solenoid and the rattling is coming from the PCV valve. The PCV valve is rattling because a vacuum is started/stopped pretty quickly making the plunger in the PCV valve jump around & rattling in its housing. I have no idea what is causing the sound in the EGR Solenoid.

No codes are being thrown, btw.

Any ideas?

 

bump bump bump...

 

Anyone?

 

Sorry you're not getting replies. I keep checking the thread though. It's a curious problem.

 

Sorry I have no idea but will watch the thread in hopes someone can help.

Matthew

 

I haven't had a chance to get near the car since I posted up this thread so I'm not really any further in figuring this out then I was when I initially posted this up. I've been out of town most of the month.

However, after noodling on this a little while, the PCV valve rattling is definitely from fluctuating vacuum bouncing the plunger in the PCV valve metal housing. The question is what would cause the fluctuating vacuum _after_ the motor had been shut off? I would expect it to just drop off quickly. I can't remember if the motor had fully stopped spinning, or if it was spinning down, or if the motor was hot or cold at the time. Could a vacuum leak or clogged vacuum line in the PCV system cause this?

As for the gurgling, I still have no idea. The EGR Solenoid is computer controlled to apply vacuum to the EGR valve. If the gurgling was due to oil/liquid in the tiny vacuum lines attached to the EGR Solenoid, I would expect it to not allow vacuum to the EGR valve so it wouldn't open as much as it should (if at all). Wouldn't that cause drivability issues or throw a code? The car runs like a top with no idle issues or codes either.

I'm a proponent of diagnosing a problem and fixing it correctly & once rather then the shotgun approach of throwing parts at a problem till its fixed. I don't have the $$$ for the shotgun approach.

Any ideas or tests I can run to help diagnose the problem?