I am another lucky Aero owner with a vacuum leak, I can hear it in the upper intake drivers side, but I cannot find exactly where it is. Tried the ether trick, no avail where exactly it is. I was hoping that it was a cap that came off of the vacuum tree, well this is the first time that I tried to find it on my Aero, and dang, I can't find it.

I am at a loss, there is a suppose to be a vacuum tree somewhere on the drivers side of the intake manifold in the back next to the PCV valve according to this pic:



But looking at this pic, I don't see a tree for the PCV to hook up to:



But Again, they show the tree in this pic:



According to the catalog, it was used in all Aerostars, but for some Reason, 97 tends to be a an oddball year.

I tried to take some pictures of it, but being dark, cold, and lack of space/light, these are the best.

Here are pics of the PCV line from the cover, and it physically connects straight to the intake:












You also see the Booster hose connecting directly to the intake manifold more forward in the pic.

So where is this Tree? Checked with the master Tech, and he said that Yes there should be one there, but it has been a while sense he worked on one. So where should I look.

I really don't want to have to tear it apart and replace all of the gaskets/hoses just to find out it was just a lost cap in a spot I could not see with everything in there.

So any ideas guys?

 

Follow that corrugated abrasion sleeve (there should be a vacuum line inside) and I would think that you'd find the tree.

Not to be overly pessimistic, but I have heard that the plastic manifold on Explorers has a tendency to leak. It looks like your intake is plastic as well. Have you ruled out the intake itself?

 

The tree should be on the rear-left side of the intake manifold, which leans over tot he driver's side. Of course, this is on my 90 and 91 models, which had aluminum intakes. Maybe the models with the plastic manifolds have the tree in a different place.

On mine, the engine would backfire if I did not start it correctly, like letting off the key too early. This will almost always pop one of the rubber caps off the tree, falling to who knows where. So I replaced two of the caps with a short length of rubber hose looped from one nipple to the other. So if the engine back fires again, it will pop off one end of the hose, and I can quickly re-connect it, instead of hunting for the stupid cap.

 

I can only see a small part of the vac. tree with a super bright light on mine '96, it's were the guys say. Real dark hole and most everything under there is black or dark colored.

Only way I found it first time was by feel, following a vac. hose to the tree with a hand. Wear an old long sleeve shirt and tape it at the wrist, the sheet metal and parts on mine are still razor sharp after 17 years.
Real contortionist bummer to put wire tie clamps on, forget trying screwdriver clamps. Reason all of us use the highest quality hi temp silicone hose we can afford and only do it once. Except for my darn EVAP system, that thing eats stainless steel.

 

Well I find out why I could not find a Vacuum tree, it is because there is NOT one on the '97 4.0L. They molded different nipples for the necessary lines on the plastic intake. So If you look at the second diagram in this pic, that is all you have:



You just have the IAC, DPFE, EGR solenoid, PCV Hose and Brake Booster Hose.

Our master tech had a minute this afternoon to take a look and he found the vacuum leak. The EVAP hose on the bottom of the Throttle Body to a plastic straight piece had become dislodged from the plastic connector causing the vacuum leak. You can see it in the bottom pic (9E498) they removed the T and just put a straight piece plastic connector.

So it looks like in the very near future I will be replacing the hose. I will post pics when that is done.



Thanks for your suggestions guys!

 

EVAP hose is the first one to break down, can cause nightmare codes that put the PCM into cripple mode. The 96's have a semi rigid molded hose that micro fractures and chemically breaks down at the bends. runs under around and across the rt. VC and IM to TB. fought that POS for 2 years. main reason I had to quit using the van to tow with.
The thin cheap molded hoses on the fumes canister/valves turn to rubbery mush in a few years.

must be full electronic cruise control in the '97? love the '96 vacuum cruise control, about the only thing I have not had to work on vac. wise since new except preventative line replacement.

how are those '97 fast burn heads on plugs and fuel?

Love the Dodge Cummins, can crawl right in the engine bay and work. just everything is heavier than hell.
can't even change a tire on it, too heavy with the arthritis.

 

96, I am in the process of changing plugs/wires, they have about 40k mi on them, but they are done for with all the in town driving I do, it does decent on gas.

As for the cruise, yes, it is electronic solenoid controlled, not vacuum. I have yet to have issues with it. When I originally purchased the van, it was disconnected and I had to lube the cable to get it to work, but it has worked ever since.