Recently I have been hearing a new sound under the hood. It is much more prominent when cold, but after the the engine warms up the sound is still there. It sounds like a low tone howl. It starts off at around 1800 rpms and hits it peak at 2100 rpms and drifts off if I go any higher. I have an appointment with the diesel tech guy on Saturday. Just wanted a heads up. By the way I am displaying a bit of coolant puke as well, Hents the appointment on Saturday. Any idea guys? 122000klm (85000miles).

 

Always hard to understands sounds over the www! Anyway, if it is a sound like blowing over the top of a coke bottle, it very well could be a head gasket leak that is relieving out the degass bottle cap.

 

I've got this same low tone howl. But it's directly caused by the CFM+ intake elbow. The extra air flow between that and my AFE intake is the reason.

I would first start by getting the most recent Degas Cap from ford $12. Then check out your elbow and cac tube hoses/tubes.