6637 Question
Senior User
Joined: Jan 2004
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From: Pugetopolis
Hotshot
Joined: Dec 2005
Posts: 10,253
Likes: 7,687
From: Chino Valley, Arizona
check post 8 thru 11 in this link
https://www.ford-trucks.com/forums/8...-6637-mod.html
https://www.ford-trucks.com/forums/8...-6637-mod.html
Senior User
Joined: Jan 2004
Posts: 475
Likes: 0
From: Pugetopolis
Nice pics. Did you notice any MPG differences after the change? I think the 6637 is one helluva filter. Napa sells it for $27 here. The one I took out a few months ago was dingy, but still looked serviceable. I still have it, so I'll try the drop-light test. It was on for about a year in some dust, but mostly street use. For me, $27 isn't too awful to refresh the thing and know I am getting the cleanest air and all the CFM I can out of it.
Based on your input, I can see leaving it on for almost two years given a cleaner operating environment or low miles.
.
Based on your input, I can see leaving it on for almost two years given a cleaner operating environment or low miles.
.
Hotshot
Joined: Dec 2005
Posts: 10,253
Likes: 7,687
From: Chino Valley, Arizona
don't know about mileage, it was a customers truck. there was no power loss and no black smoke so no restriction. I can't remember the last time I change mine in either on of my trucks.
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