These MN12 cars haven"t been built because 1997. For this reason that way that all MN12 Thunderbird & Cougars are 20+ years old. Among the things that goes poor over time, and not necessarily street is the rubber hoses ~ above the emissions system. Small rubber vacuum / emission hoses have the right to only critical so long under the consistent under-hood heat and also road conditions.

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If the emission hoses under the hood the your vehicle are original, it"s time to change them now, quite than wait. If you wait, it can lead come air leaks and also cause idle or drivability problems, and also most likely some diagnostic trouble codes like a P0171 or P0174. Your automobile may no idle right. The allude is it"s precious the $25 or so essential to replace the hoses to ensure reliability of your car.

Now I have to admit the 99% of the time I purchase OEM parts. I"ll walk to the dealer or shop online to acquire the top quality of a actual Ford part. I"ve heard the Ford/Motorcraft components are draft to last 160,000 mile so periodically they cost more, yes sir usually. In this situation where we"re simply replacing tiny lengths of emission hose, it"s most likely not crucial to get OEM parts. For example, ns inquired in ~ the dealer about replacing one section of hose and also I would certainly have had to buy a totality kit v two rubber end pieces and also the plastic part in the middle and just that part was $30. Well the plastic part of mine setup to be fine, therefore I simply went come the neighborhood auto components store and also bought emission hose.

Note the these instructions use to many much more Ford 4.6L & 5.4L V8 engines besides just the T-bird. This same procedure applies to Mustang, F-150, Crown Vic, etc. Although your hoses may be routed contempt differently.

Another thing to be aware of is the you cannot use constant vacuum water tap to replace emission hoses. You must use emissions water tap (or fuel line hose) on those hoses. Continuous vacuum hoses simply aren"t strong enough come work. The auto components store may try to market you fuel injection hose, that form of hose is rated to take care of a lot greater PSI (pressure) and is no necessary. As far as I recognize it will certainly work, yet again it"s no necessary. I check out there are silicone hoses on the market, I have no experience with lock so ns can"t say if they would work.

According to the factory Ford organization manual, part (or all?) vacuum hoses are color coded. The manual mentions red and green striped hoses yet I couldn"t tell if my lines had actually stripes or not, they were as well old. Because that our objectives we don"t require the color stripes anyway. There must be a little sticker under the hood or ~ above the front radiator assistance area labeling Vacuum water tap Routing, refer to that top top your vehicle to see where all her lines run.

Required components & Tools

In mine case, ns bought the following amounts of this hoses for my 4.6L V8 equipped car:

So I checked out the neighborhood auto parts store because that the stuff, but the complete for those components was a bit much less (they offer hose by the foot even though you won"t usage it all just buy what the quantities I mentioned).

Generally, this procedure should use to all 1994, 1995, 1996, and also 1997 T-Birds & Cougars through the 4.6L V8 engine. The procedure will be comparable for 3.8L V6 and also 5.0L V8 equipped cars, so describe your underhood vacuum water tap routing brand for more details. There is a minor difference for the 1994/1995 4.6L cars, if your auto is 94 or 95, view the keep in mind at the bottom the this article!

As for tools, really all you require is a sharp energy knife or possibly scissors to cut the hoses. You want nice clean cuts, preferably.

What I"m no including below is exactly how I determined what water tap sizes i needed. I used a digital micrometer and also measured the interior diameter of the present hoses and the outside diameter of the points they connect to. I established what is the the next size and that"s exactly how I arrived at the three sizes: 1/4", 3/8", and also 5/8". Technically the hoses can be a really slightly different size but every one of the hoses to the right OK. If you obtain a water tap diameter that is too huge you risk having actually a vacuum leak.

First off, to placed this in perspective, this is every my old hoses laid the end after I replaced them with new pieces. As you have the right to see, they space crumbly and also no doubt had a couple of minor leaks in them. When you touch the hoses, castle leave black color on your hands which means something is not normal. Vacuum leaks are not good, for this reason let"s acquire started on replacing them.


One much more thing prior to we start, here is a diagram through approximate areas of the hoses under the hood. The green marks in the photo apply to 1994-1995 cars:


I started by replacing the brief section of 5/8" water tap coming off the drivers" next valve cover. Merely twist and also remove the brief section of hose, place it beside your 1ft size of 5/8" hose, and also cut therefore the length is about the same. The doesn"t have to be specifically the exact same length but keep that close to the same length to make it easier. Ideally you should use emission hose here, however using the heater water tap isn"t a large deal. You certainly don"t want to use heater hose on anything the will have actually vacuum, as the hose will collapse. The auto components store i was at only had actually heater hose in 5/8" diameter and that"s OK for this certain application. If they had 5/8" emissions hose i would have used that. As result of the oil/fuel vapor that might come in call with the hose, the water tap may break down sooner 보다 the OEM hose, so the will have to be changed sooner 보다 the other hoses/lines. Again, this is a cheap fix so it"s OK here :-) Here"s a photo of the chauffeurs side rotten hose:


To make points easier, I removed the wait duct going from the MAF (mass airflow) sensor come the accelerator body, which additionally has a smaller duct running ago to the former of the accelerator body wherein the IAC (idle waiting controller) is.

Next, I provided a small section the the 3/8" fuel hose to replace the crumbling hose connecting from the passenger side PCV (positive crankcase ventilation) valve come the plastic tube the runs up to the intake.

PCV valve emission hose


While I"m at it, shiver the PCV valve as soon as you have it out, view if it rattles. Typically if that rattles, it"s tho good, if the doesn"t, it"s time to change it. That"s simple DIY maintenance job to do.

Next up I changed a length of hose that runs throughout the passenger next valve cover. This offers the 1/4" fuel heat hose, around 5 inches long. Again, take the old water tap off, hold it up to the brand-new hose and cut off about the same length of hose.


Next increase I changed the L shaped hose the comes directly out the ago of the accelerator body and goes off towards the passenger next of the car. The initial hose may have been molded with the bend, but I offered a straight piece of 1/4" fuel line hose and also it conformed well sufficient for my purposes. This water tap was yes, really rotten and also cracked on mine car.


There is a similar hose, exact same size L-shaped coming turn off the front of the accelerator body, replace that one too. Ns don"t have a snapshot handy yet it has actually the exact same bend off toward the passenger side of the engine.

Next I found a little short piece of water tap down previous the air intake box. So, I eliminated the air crate to make it much easier to access, I indicate you perform the same. Usually the emissions line that runs over the passenger side valve sheathe (remember you simply replaced a section of the hose earlier), well, it leads to a plastic item of line, climate this small rubber connector goes between that and also another strict plastic line. You have the right to see that in the very center the this next photo:


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

So, what you"ll check out down over there is the charcoal canister i beg your pardon is part of the EVAP (evaporative) emissions system. It has actually some strict plastic lines, wiring, connectors, etc. Over there is a U-shaped piece of tubing/hose and also that has a couple of small rubber pieces that need replacement too. Here is a photograph of the area through the charcoal canister in place prior to I did anything. The various other photo reflects the U shaped piece that I eliminated as a unit (you should disconnect one wiring connector, you"ll watch which one), and also that allowed me to easily replace the tiny pieces and put the all back together.



The previous 2 photos use to 1996 & 1997 Thunderbird & Cougars. 1994 & 1995 version year vehicles have a really slight distinction at the canister. Rather of one line going in, there are two, together you can see in the complying with photo courtesy the TBIRD9491. So there room 3 tiny pieces the 1/4" heat that require replacement:

1994 / 1995 Models:


In enhancement to the hoses presented above, TBIRD9491 discussed some various other hoses in the fuel device that may need replacement. There is one water tap in front of the fuel filter (you may need to loosen the fuel filter bracket and also pull it under slightly to make it much easier to access), over there is one water tap behind the fuel filter, and also one close to the fuel tank. FYI the fuel filter is situated basically under the front passenger"s feet, under the car. The two rubber present in front and also behind the filter might be simplest to accessibility by cutting/removing both and removing the plastic piece in in between them (it"s on the exact same line), then putting on brand-new rubber pieces and reinstalling:

In former of the fuel filter


Behind the fuel filter


Here is what TBIRD9491 has to say concerning the hose near the fuel tank, along with a photo:

Follow it some more and it goes up into a space along the fuel tank. This is a ache to gain off and also on, So it takes some patience. I provided the flat head to obtain the metal line side off while pulling up. Then to gain it turn off i supplied the square pliers and pulled down . To install i got hold of the plastic line through needle nose"s organized it in ar while advertise the water tap on ; then for the metal line seize the hose with needle nose and also push down while pushing steel line up. (Note - just 1in or 2in an are so take her time)


Well the covers the hoses that ns replaced. I acquired all the rotted rubber hoses replaced that I might see, let me recognize in the forum if I have actually missed anything, or if girlfriend have any type of feedback or comments on this article.

UPDATE: another hidden EVAP hose found!

Since creating this article, nall_one discovered an extra hose and also notified me. Many thanks for discussing a concealed hose! You have to remove the passenger side inner fender (plastic) liner to accessibility it. Mine was rotten, check it out:


Extra keep in mind for 1994 1995 4.6L Cars

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

First is a Tee in the vacuum routing system. The leaks sometimes, so right here is a photo of the T, it"s kind of concealed behind the throttle body and plenum top top the passenger side. That is circled in the following photo (sorry i don"t understand the source of this pic). A tip is to follow the plastic vacuum line turn off the PCV and also it will lead back 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 the goes turn off from the Tee towards the vehicle drivers side then goes right into a plastic tube, and at the other finish of the plastic tube is an additional short rubber piece. This is azer to gain to, the line runs under the plenum / accelerator body along the fuel line into the entry manifold.

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TBIRD9491 contributed this snippet regarding the T:

I disconnected the various other rubber item (other side) turn off of the input maniold, by squeezing part needle nose pliers and also working it off. It"s a very tight squeeze, have to be careful not come pinch or rest fuel line. Then ns pulled towards me by grabbing the rubber water tap I simply pulled off. Which came out through the plastic tube the goes throughout and connects come the T.