first time user: hope i'm doing it right...2003 e-350 7.3 developed a VERY LOUD metallic slap at 70 to 80 mph. comes from passenger side probably high up behind dash, or possibly frame/chassis accessory. definitely not engine or drive train, happens at lower speeds driving into stiff wind. removed shields, taped off air louvers at top of firewall, varied heat/cool and fan speed all to no avail. long trip coming up i really hope someone else has experienced this or can offer possible fixes. thanks

 

Welcome on a board.

 

thanks, been meaning to join for a long time.

 

Sounds like it could be a loose cabin air filter.

 

thanks for the speedy reply hanky. i have the workshop manuals for this van but i can't find any reference to a cabin filter. it feels to me like it is in the air/vent system too..does my attempt to eliminate that by taping off the cowl air intake make sense?

 

Does your van have an electric or mechanical vacuum pump to operate the ventilation controls?
Is any particular heater function selected when this happens?
Maybe you can get different results when different functions are selected?
Does it sound to you like a vent door slapping? Just trying to eliminate the vacuum/ HVAC systems.

 

I dont every recall the E series using a cabin air filter, but I could be wrong.

 

hello again from a guy who can't operate a phone who expects to successfully navigate a forum via computer... anyway.. i thought my reply to hanky went through. guess i'll try again. controls for hvac are vacuum. there is no difference whether the control **** is on a/c, heat, any fan speed or vent. it certainly could be a vent door and i have found its location in the workshop and will inspect/test it friday or saturday. thanks again for your suggestions and thanks to greasemark..turns out that there is and aftermarket filter but not from factory in this model.

 

What happens if you slow down to say 45MPH and then go back up to 70MPH. Does it happen again?


This reminds me of another situation where they hung a soda bottle from a piece of string on the assembly line and it drove the owner and mechanic nuts trying to find the noise. When it was found, there was a note inside that read , Ha Ha you found me !

Will never forget that One !

 

slow down and again reach speed same thing happens. only caveat, if the wind is blowing into my face, speed to attain noise lowers... i.e. total wind into front of van needs to be 76 to 80mph. opened the access to vacuum controls for hvac.; all work as should--respond to positions on control ****. pretty much feel like hvac is eliminated. took my wife to listen.. she also feels like it is coming from passenger side, most likely behind dash. scary loud noise!!