I'm reposting this as I did'nt get any feedback but still have the screeching or vacuum noise at cold startup. If the Ford tech whom I've seen on the forum could check on this or direct me to someone with Ford Trucks, it would be greatly appreciated. Or if someone knows how to go direct to an online tech. Thanks and I enjoy the forum.

New to forum. I drive a 2011 F250 6.7L Has about 15000 miles. Runs great, and pulls our 12000# 5th wheel all over the western US with ease. What a great engine and comfortable truck. About a month ago I noticed an odd screeching or vacuum type noise about 2 seconds after the engine starts. Only lasts a about half second. It will only make this noice on a cold startup even in the warm summer weather. Doesn't make the noise after minimal warmup starting. Had my Ford dealerships diesel tech check it out. He says he was able to replicate the noice by manually activating the waste/dump valve behind the turbo. And claims he got a code on the computer for the same. Replaced the valve, but still the same noise. Since it sounded somewhat like a scweeky belt, they put a new drive belt on. Still has the screaching noise at cold startup. If anyone has encountered this noise with their 6.7l please post. Thanks to all in advance. GHPHOTO

 

You wouldn't happen to have a video would you?!

 

I can surely do an audio recording and repost with it. Thanks.

 

I would pull the belt back off and spin each of the pulleys when cold. One of the bearings could be dragging enough to make the belt squeal.

 

With 42K miles I have exactly the same symptom. I left the truck with my dealer and they were able to duplicate the noise at start up the next morning. They called Ford and were told it's nothing to worry about. All this started a few couple years ago. It's still there but not any worst.

Rob

 

Rob,
Thanks for your post. Glad to finally find another 6.7L owner with the same symtom. The dealership has essentially told me the same thing. Don't worry about it. If anythings really wrong it will likely get worse. Mine has stayed pretty much the same over two months and now cooler weather.. As a past diesel mechanic myself (caterpillar) it doesn'nt seem totally unual to have a sqweaking noise like this, considering all of the valves, solenoids etc attached to this engine. Another formum member suggested a bearing in an idler, which it could be, but I need to get back to my tech, as I think he checkecd all of the idlers. As to a belt slipping on a pully or idler, there are belt cogs on all of idlers and the drive belt is cogged on both sides. Thats pretty slip free unless a bearing completely seizes up. I will try and get an audio recording at startup and post it. Thanks again Rob and all.

 

I know what you mean as that is exactly what it sound like.

Rob

 

Quick way to eliminate the belt from contention as well as any other belt driven accessory is to remove the belt and try it.. Only for a few moments, but that should confirm that theory.
There may be a slight lag in the retraction of the starter bendix from the flywheel. This will make a God Awful screech as the overunning clutch in the starter bendix struggles. Be careful to not rev the engine as it can permanently damage the starter and possibly the flywheel..
Good luck on finding the solution!

 

Sorry to bring up and old thread, did you ever find the cause of this noise ? Mine has started doing it.