Hey all, I have a 2003 E450 Ford transit bus conversion with the 7.3. This has been my first diesel and although I have a few years of being a gm tech with gas engines, it's been a learning curve with my first ford diesel. His site has been a great help for me. My heater/AC only blows via defrost which I am aware is the default setting should a vacuum leak occur. I've read several posts about the 4wd hubs being a source for many cracked lines causing leaks but my 7.3 is 2wd so I'm looking for other common places to check, or if anyone has a diagram for the vacuum lines to trace. Also, how exactly do you go about a diy method of testing the vacuum pump its self? Any leads would be much apprexisted!

 

I believe that your E-450 has an entirely different system than our F model trucks. When I parted out my E-450 short bus I found a belt driven vacuum pump on the right hand side of the engine and IIRC there is a round tank somewhere nearby. Ours have a small electric pump on the passenger's side fender and an oval tank nearby. God bless you and good luck working on it, all I did was tear mine apart but I took note on how hard everything is to get to on it.

Edit: That is not to say that nobody here will be able to help you, there might be. There is also a forum dedicated to the E model trucks that you might want to check in as well. https://www.ford-trucks.com/forums/forum128/

 

Thank you Walleye. Yes, I've had quite the experience working on this thing. I might consider myself a fairly knowledgable diesel tech after owning this thing for almost a year. When I purchased it, nothing seemed to work. No AC(fixed by replacing Ac line AND both high and low pressure switches), blower innop(replaced), new water pump, trans cooler, new fuel lines after rubbing holes caused massive fuel leak, repealed hpop, new ICP sensor, new IPR pigtail due to wire chaffing, resell fuel bowl, both new batteries, about to test and change glow plugs due to no start in cooler weather, new oil line fittings at cylinder head, ect ect. The struggle is real!

 

Back to yoir original reply. Yes, my van style has a belt driven pump on the right hand side of the motor. When I purchased the vehicle at 212K, the blower was innop. I replaced it and the air (both AC/Heat) did in fact blow through the vents for a short while before defaulting to defrost. It sounds like I can maybe hear the pump making noise when being belt driven. I Wouldn't call it a bad noise per say, just a buzz or hum I guess. Just looking for ways to test it or some common places to start searching for cracked lines. Ect

 

Find the line coming off the pump and going to the reservoir. Pull it off and put your finger or a piece of plastic against it. It should hold the plastic against the open tube if you are making vacuum, or you will feel it against your finger as well.