When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
The heater in my 03 f350 seems to take a long time to make heat, even though the engine is at 180. (I have a real guage.) When its very cold, the dash vents don't open or take a long time to open, and the other day, I stepped down on the gas and the dash vents closed again. It didn't unlock the converter, but strained the engine enough to lower the vaccuum, I guess. Could this do it, or do I need to look for a leak? The esop works fine- we've had lots of snow to use the heater and 4wd at the same time. Where is the vaccuum line under the hood? If I pump up vaccuum there, should it hold it at each setting? I searched these forums and didn't find the answer. I just replaced the light switch, but only because the **** was broken. Could it be the heater doors are just stiff when its really cold? Thanks, guys.
The vacuum hose is probably going into the firewall on the passenger side. Follow the line from the vacuum reservoir (big black thing right behind the battery). It should t-off somewhere and disappear into the firewall. Disconnect that and put vacuum on it, and it should hold it.
The reservoir I think is known to crack and leak. But, the ESOF wouldn't work right I don't think.
But you're right questioning why the heater goes wild when you step on the gas too long. Something is not holding vacuum.
Wow! lots of little vaccuum tubes. I found the one that controls the heater and the heater holds 20 inches as long as I left it. The plastic tank holds vaccuum just as long, but with everything hooked up there is only 4 or 5 inches. I followed the lines to what I guess is a vaccuum switch®ulator (?) for the esof. It leaks enough vaccuum so the supply line can't keep up. Of course, I picked it all apart and need a new one. It's marked PA66-GF33 so I'll now try to find one. Hope I'm on the right track here.
Having a hard time finding it online. The dealer parts guys around here are sadly mostly gone and the nearest are closed. As soon as I find one I'll post the result and how I got it.