These MN12 car haven"t to be built since 1997. For this reason that method that all MN12 Thunderbird & Cougars room 20+ year old. Among the points that goes poor over time, and also not necessarily street is the rubber hoses top top the emissions system. Little rubber vacuum / emissions hoses have the right to only critical so long under the continual under-hood heat and road conditions.

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If the emissions hoses under the hood of your automobile are original, it"s time to change them now, fairly than wait. If friend wait, it deserve to lead to air leaks and also cause idle or drivability problems, and also most most likely some diagnostic problem codes like a P0171 or P0174. Your car may no idle right. The point is it"s precious the $25 or so needed to change the hoses to ensure dependability of your car.

Now I have to admit the 99% of the moment I buy OEM parts. I"ll walk to the dealer or shop online to gain the quality of a genuine Ford part. I"ve heard the Ford/Motorcraft components are design to critical 160,000 mile so sometimes they expense more, ok usually. In this situation where we"re simply replacing tiny lengths of emission hose, it"s likely not an important to acquire OEM parts. Because that example, ns inquired at the dealer around replacing one section of hose and also I would certainly have had actually to to buy a entirety kit with two rubber end pieces and the plastic part in the middle and just that component was $30. Fine the plastic component of mine setup was fine, for this reason I just went to the local auto components store and bought emissions hose.

Note the these instructions apply to many an ext Ford 4.6L & 5.4L V8 engines besides just the T-bird. This same procedure applies come Mustang, F-150, Crown Vic, etc. Although your hoses might be routed slightly differently.

Another thing to be conscious of is the you cannot use continuous vacuum water tap to replace emission hoses. You have to use emissions hose (or fuel heat hose) on those hoses. Regular vacuum hoses just aren"t solid enough to work. The auto parts store may shot to sell you fuel injection hose, that form of water tap is rated to manage a lot greater PSI (pressure) and is not necessary. As much as I know it will certainly work, however again it"s no necessary. I see there are silicone hoses ~ above the market, I have actually no suffer with castle so i can"t say if they would work.

According to the factory Ford business manual, part (or all?) vacuum hoses are color coded. The hands-on mentions red and also green striped hoses however I couldn"t phone call if my lines had stripes or not, lock were as well old. Because that our purposes we don"t require the color stripes anyway. There must be a little sticker under the hood or ~ above the prior radiator assistance area labeled Vacuum hose Routing, describe that ~ above your vehicle to watch where all your lines run.

Required components & Tools

In mine case, i bought the following quantities of these hoses because that my 4.6L V8 fitted car:

So I visited the local auto parts store for the stuff, yet the complete for those parts was a bit much less (they offer hose by the foot even though friend won"t use it all just buy what the quantities I mentioned).

Generally, this procedure should use to every 1994, 1995, 1996, and also 1997 T-Birds & Cougars with the 4.6L V8 engine. The process will be comparable for 3.8L V6 and also 5.0L V8 fitted cars, so refer to your underhood vacuum water tap routing label for an ext details. There is a minor difference for the 1994/1995 4.6L cars, if your automobile is 94 or 95, see the keep in mind at the bottom of this article!

As for tools, yes, really all you need is a sharp utility knife or probably scissors to reduced the hoses. You want nice clean cuts, preferably.

What I"m not including listed below is just how I determined what water tap sizes ns needed. I provided a digital micrometer and also measured the inner diameter that the existing hoses and the exterior diameter that the things they attach to. I figured out what is the the next size and that"s just how I arrived at the three sizes: 1/4", 3/8", and 5/8". Technically the hoses might be a very slightly different size but all of the hoses right OK. If you get a water tap diameter the is too huge you risk having a vacuum leak.

First off, to put this in perspective, this is every my old hoses laid out after I replaced them with new pieces. As you deserve to see, they space crumbly and also no doubt had actually a few minor leaks in them. When you touch the hoses, castle leave black color on your hands which method something is not normal. Vacuum leaks space not good, therefore let"s get started on instead of them.


One more thing prior to we start, below is a diagram v approximate locations of the hoses under the hood. The eco-friendly marks in the photo apply to 1994-1995 cars:


I began by instead of the short section of 5/8" hose coming turn off the drivers" side valve cover. Just twist and also remove the brief section the hose, put it beside your 1ft size of 5/8" hose, and also cut for this reason the size is around the same. That doesn"t need to be exactly the very same length yet keep that close come the same length to make it easier. Ideally you need to use emission water tap here, however using the heater water tap isn"t a big deal. You definitely don"t want to usage heater hose on anything the will have vacuum, together the hose will certainly collapse. The auto parts store i was at only had heater hose in 5/8" diameter and that"s OK because that this specific application. If they had actually 5/8" emission hose i would have actually used that. Because of the oil/fuel vapor that might come in contact with the hose, the water tap may break down sooner than the OEM hose, so it will have to be replaced sooner 보다 the various other hoses/lines. Again, this is a cheap settle so it"s OK right here :-) Here"s a photograph of the drivers side rotten hose:


To make things easier, I removed the waiting duct going native the MAF (mass airflow) sensor come the accelerator body, which also has a smaller sized duct running ago to the prior of the accelerator body where the IAC (idle waiting controller) is.

Next, I used a little section that the 3/8" fuel hose to change the crumbling hose connecting from the passenger side PCV (positive crankcase ventilation) valve to the plastic tube the runs approximately the intake.

PCV valve emissions hose


While I"m at it, shake the PCV valve once you have actually it out, watch if the rattles. Normally if the rattles, it"s tho good, if that doesn"t, it"s time to replace it. That"s straightforward DIY maintenance job to do.

Next increase I changed a length of hose the runs throughout the passenger side valve cover. This offers the 1/4" fuel line hose, roughly 5 inch long. Again, take it the old hose off, organize it as much as the new hose and also cut off around the same size of hose.


Next increase I replaced the L shaped hose the comes straight out the ago of the accelerator body and also goes off toward the passenger side of the car. The original hose may have actually been molded through the bend, yet I supplied a straight piece of 1/4" fuel line hose and it conformed well enough for my purposes. This hose was really rotten and cracked on mine car.


There is a comparable hose, same size L-shaped coming turn off the prior of the throttle body, replace that one too. I don"t have actually a photo handy but it has actually the very same bend off towards the passenger next of the engine.

Next I uncovered a small short piece of hose down previous the wait intake box. So, I eliminated the air crate to do it much easier to access, I indicate you perform the same. Usually the emission line that runs end the passenger next valve covering (remember you just replaced a section of the hose earlier), well, it leads to a plastic piece of line, climate this little rubber connector goes in between that and another strictly plastic line. You can see that in the an extremely center that this next photo:


That"s it for what I replaced "under the hood". I traced the line the I simply replaced the tiny connector line and also noticed that it goes under underneath. The inner fender. So... I took off the right front wheel and removed the plastic fender shield for less complicated access. Plus that made it a lot easier to take images :-)

So, what you"ll view down over there is the charcoal canister i m sorry is component of the EVAP (evaporative) emissions system. It has some strictly plastic lines, wiring, connectors, etc. There is a U-shaped item of tubing/hose and that has actually a couple of small rubber piece that need replacement too. Below is a photograph of the area through the charcoal canister in place prior to I did anything. The other photo shows the U shaped item that I removed as a unit (you need to disconnect one wiring connector, you"ll see which one), and that enabled me to easily replace the tiny pieces and also put the all ago together.



The previous 2 photos apply to 1996 & 1997 Thunderbird & Cougars. 1994 & 1995 model year vehicles have actually a very slight difference at the canister. Instead of one line going in, there are two, as you can see in the following photo courtesy of TBIRD9491. Therefore there space 3 small pieces of 1/4" heat that require replacement:

1994 / 1995 Models:


In enhancement to the hoses displayed above, TBIRD9491 stated some various other hoses in the fuel system that may need replacement. There is one water tap in prior of the fuel filter (you might need to ease the fuel filter bracket and also pull it down slightly to do it easier to access), there is one water tap behind the fuel filter, and one near the fuel tank. FYI the fuel filter is situated basically under the front passenger"s feet, under the car. The 2 rubber lines in front and also behind the filter may be simplest to access by cutting/removing both and also removing the plastic piece in between them (it"s ~ above the very same line), then putting on brand-new rubber pieces and reinstalling:

In front of the fuel filter


Behind the fuel filter


Here is what TBIRD9491 has to say about the hose close to the fuel tank, in addition to a photo:

Follow it some much more and the goes up right into a an are along the fuel tank. This is a pain to acquire off and also on, So the takes some patience. I used the flat head to acquire the steel line side off while pulling up. Climate to get it turn off i offered the square pliers and also pulled under . To install i ordered the plastic line v needle nose"s hosted it in place while advertise the water tap on ; then for the steel line grab the hose with needle nose and also push under while pushing metal line up. (Note - just 1in or 2in room so take your time)


Well that covers the hoses that i replaced. I acquired all the rotted rubber hoses replaced that I could see, let me know in the forum if I have actually missed anything, or if you have any type of feedback or comment on this article.

UPDATE: another hidden EVAP hose found!

Since composing this article, nall_one uncovered an extra hose and notified me. Thanks for discussing a hidden hose! You need to remove the passenger next inner fender (plastic) liner to access it. Mine was rotten, check it out:


Extra note for 1994 1995 4.6L Cars

NOTE: If you have a 1994 or 1995 4.6L car, there are two additional 3/8" hoses to be conscious of.

First is a Tee in the vacuum routing system. The leaks sometimes, so below is a picture of the T, it"s kind of covert behind the throttle body and also plenum ~ above the passenger side. It is circled in the complying with photo (sorry ns don"t understand the resource of this pic). A reminder is to follow the plastic vacuum line off the PCV and also it will certainly lead ago to this T. If you need to replace it, look because that a Ford part number F7LZ-6B899-AA or a Dorman HELP! component number 47072:


Secondly, the tube that goes turn off from the Tee toward the motorists side climate goes into a plastic tube, and at the other finish of the plastic pipe is another short rubber piece. This is azer to obtain to, the line runs under the plenum / accelerator body follow me the fuel line right into the entry manifold.

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TBIRD9491 added this snippet regarding the T:

I disconnected the various other rubber piece (other side) turn off of the intake maniold, by squeezing some needle sleep pliers and also working it off. It"s a very tight squeeze, need to be cautious not come pinch or rest fuel line. Then ns pulled towards me by grabbing the rubber water tap I just pulled off. Which came out with the plastic tube the goes throughout and connects come the T.