Mondeo 2008 2.0TDCI 140 - My Mondeo Groans, or MOOS when I turn it off.

Honest John Back Room » Technical matters
View Threaded
Fri 13 Sep 2013 16:56
Mondeo 2008 2.0TDCI 140 - My Mondeo Groans, or MOOS when I turn it off. - Mr Fox

My Mrs has a Mondeo, and when the engine is turned off, it emits this "moo" or groan for about 7 seconds, It sounds like maybe a cooling fan or somethign like that, but I cannot pinpoint it.

Also sometimes, but not always, there is a very faint whistle coming from behind the dashboard, again i can't find where from, the only thing that affects it slightly is turning the steering wheel when its Idling.

I think it sounds like a Cambelt tensioner bearing but really cannot pinpoint where its comign from.

Don't know if there is a link between the mooing and this, but would be grateful for any advice on it.

Reply | Report as offensive | Link
Fri 13 Sep 2013 17:44
Mondeo 2008 2.0TDCI 140 - My Mondeo Groans, or MOOS when I turn it off. - Pablo202
Hi there,
This may not help but my work colleague had a mondeo, roughly same age, that did the same thing. It was most annoying. It did it for two years and did it every time he switched off. It's like the car says " ERRRRRRRR" from the middle of the dashboard but in the engine bay. We never traced it and when it went in for its service, the garage never sorted it. I don't think it had anything to do with the cam belt. Sorry I can't help, but you're not alone.........well you may be as the car went last year!!!!
Hope someone helps more than I did!!
Pablo.
Reply | Report as offensive | Link
Fri 13 Sep 2013 18:01
Mondeo 2008 2.0TDCI 140 - My Mondeo Groans, or MOOS when I turn it off. - craig-pd130

My 2008 Mondeo started to do that just before the end of my contract hire, and from the Mondeo forums it seems to be quite common.

It's the solenoid valve that controls the variable nozzle mechanism on the turbo. When the engine's running, it's under vacuum and switches the vacuum to open or close the vanes in the turbo to increase or decrease boost.

When you switch off, the vac pump on the engine stops, and atmospheric pressure bleeds into the system through a cap on the valve, causing the mooing sound. It's the brown-coloured plastic valve on the right side of the engine as you look at it.

Some replace the valve, some don't bother. I think you can remove the cap to clean an internal filter, but I've never done it on the Mondeo.

EDITED to add that it usually doesn't affect performance or economy. If it does, change the valve.

Edited by craig-pd130 on 13/09/2013 at 18:02

Reply | Report as offensive | Link
Fri 13 Sep 2013 18:22
Mondeo 2008 2.0TDCI 140 - My Mondeo Groans, or MOOS when I turn it off. - Peter D
Turn the air con off. This may be your Air Con depressuring when you turn off. Regards Peter
Reply | Report as offensive | Link
Fri 13 Sep 2013 18:43
Mondeo 2008 2.0TDCI 140 - My Mondeo Groans, or MOOS when I turn it off. - Mr Fox
Turn the air con off. This may be your Air Con depressuring when you turn off. Regards Peter

Interesting replies, I must say the performance and economy are all fine, about 44MPG and it pulls well.

Will look for this valve and see if anything showing.

Reply | Report as offensive | Link
Sun 22 Sep 2013 21:10
Mondeo 2008 2.0TDCI 140 - My Mondeo Groans, or MOOS when I turn it off. - Mr Fox
Isolated the air con, does not affect whether this if on or off.

Sounds more electrical, can hear a relay clicking during the few seconds it does this after switching off. Also I started the engine for a few seconds, and never drove off, so turbo not used. And noise occurred the same...

second noise, tiny intermittent whine from engine bay, not related and probably a dry bearing in the PAS pump pulley ?
Reply | Report as offensive | Link
Sun 22 Sep 2013 21:15
Mondeo 2008 2.0TDCI 140 - My Mondeo Groans, or MOOS when I turn it off. - craig-pd130

As mentioned, it's the solenoid valve that controls the VNT mechanism on the turbo. As soon as you start the engine, the vac pump creates vacuum in all the lines. When you switch off, atmospheric pressure bleeds into the valve through a small hole, to return the vac actuator to a resting state.

Over time the small bleed hole can get part-blocked, causing the sound.

Reply | Report as offensive | Link