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How to change intake on 4.6L V8

Discussion in 'Stock 2002 - 2005 Explorers' started by pet575, July 2, 2012.

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    1. pet575

      pet575 Active Member

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      This job is required when your intake starts to leak coolant around the thermostat housing or leaking coolant in places that you cannot see and dumping the coolant down into the coil pack/spark plug well.

      The new part is $400+ at the dealer or you can get it online for $160-ish. It is a Dorman 615-175. I chose to go this route.

      There is a lot of unplugging of connectors/removal of parts to do this job and it is time consuming. However, it CAN be done with your everyday tools you'd have in your garage. The only "specialty" tools required are the quick disconnect tools for fuel lines (set of 4 was $10 at O'Reilly) and a torque wrench. I was able to accomplish the rest of the repair with a set of metric/sae sockets (with 3 different length extensions) and a set of metric/sae open end wrenches. A flat head screwdriver, a set of pliers, and some wire or a wire hanger also came in handy. A flat razor, a vacuum of some kind, and a can of compressed air is also nice to have for cleanup once you get the old intake removed.

      I didn't take a ton of pics because a lot of what you have to do is self-explanatory when you see the new part: you've got to get everything that sits on top of the engine OFF or at least moved to the side.

      First steps:
      (1) unhook the negative battery terminal and cover the battery with a heavy cloth (you could also remove the battery but it can be left in). A lesson that I sort of thought of later was "how will I relieve fuel pressure?" because I figured out i needed to do it once I got to the point I was at in the pic below. So, you really should pull the fuses/relays for the fuel pump FIRST and run the vehicle until it dies and THEN disconnect the battery. (More on this later, though)
      (2) drain the coolant using the petcock on the bottom, passenger side of the radiator. If the coolant has been the vehicle for several thousand miles, keep it for recycling and replace it with new coolant.

      I got to the point shown in the picture below by removing the air intake and unplugging all of the electrical connectors to the air intake and throttle body. I removed the PCV valve's connector to the passenger side valve cover first and then moved the entire tube over to the outside of the driver's side of the hood. I never removed the PCV valve itself.

      I also removed all of the coolant hoses on top, the top alternator bracket, and unplugged all of the injectors and coil packs (injector plugs are the grey plugs with the red centers). Then, I removed the bolts from the EGR valve from the side of the throttle body WITHOUT hardly moving the EGR valve at all. I was advised to be very careful with the EGR valve because it is brittle, so I hardly touched it by doing this.

      After that, I disconnected all electrical and vacuum connections from the throttle body and removed the 5 throttle body mounting bolts. I left the throttle cables and other complex-looking connections to the throttle body in place and just lifted it up and suspended it using wire.

      That got me to the point in the first picture below.

      [​IMG]
      Everything removed with direct access to intake. Throttle body suspended and out of way. EGR valve/tube still in original location-it is the flying saucer looking piece directly to the right of the air intake hole.

      Then I disconnected the fuel line from the fuel rail. There is no Schraeder valve on this assembly so fuel pressure could be an issue. I was a little concerned about this because i had NOT pulled the relay or fuse with the vehicle running to relieve pressure. BUT, the vehicle had been sitting for 20+ hours so I pulled the fuse and relay anyway (even though it was too late) and then proceeded on the theory that there would not be too much pressure since it sat for all that time. I was armed with safety goggles and several rags and when I disconnected the fuel line and.........about a thimble full of fuel came out so that was relatively easy and I was able to remove the bolts holding the fuel rail to the intake and then just firmly pulled up on the fuel rails to remove them. Without the mounting bolts, all that holds them in are o-rings.

      From this point there are 8 bolts that hold the intake on and one bolt in the front left near the alternator. Once you undo these, the intake lifts out but you MUST remove the alternator in order to actually lift out the intake.


      [​IMG]
      Top of engine with alternator and fuel rails removed and intake lifted out. You can see the EGR valve/tube still in the same place. The intake can be lifted at the front end and then pulled forward toward the radiator to slide it out without disturbing the EGR too much.


      [​IMG]
      More of a pulled-back view of everything.


      [​IMG]
      Close up of everything after a little clean-up. I went back for more cleanup with a flat razor blade and got it a little more clean. Also vacuumed a lot of dust and junk out from the areas around the spark plug wells and the injector wells. I tucked a rag in each injector port and then blew out the plug wells with compressed air while holding the vacuum right next to it. I removed a LOT of busted up plastic pieces from the top of the engine and then vacuumed the top of the engine as well as I could while I was in there.

      I had some issues with leakage of coolant in my plug wells and had previously replaced the COP and spark plugs in cylinder #5 (driver's side front) and #8 (driver's side, nearest the firewall) and also the spark plug in cylinder #6. I bought 5 more spark plugs to finish out replacing them all and went ahead and did that after removing the old intake. It was VERY easy with all of this access room and I highly recommending changing your plugs if you are doing this repair and haven't changed them. This vehicle has 204,000 miles on it and those 5 remaining plugs were stock. :eek:

      Once I got the old intake out, I was in complete disbelief as to its condition. It was in horrible shape!

      [​IMG]
      This is the thermostat housing. The dark metal on the left side of the assembly is what you see on top when installed and it is where the thermostat goes. The plastic on the bottom was literally cracking apart and falling off. No wonder it was leaking so bad!


      [​IMG]
      Zoomed out pic of the entire assembly. Note that I did NO damage to this part while removing it. This is how bad of shape it was in!!!!


      [​IMG]
      Driver side of intake


      [​IMG]
      Under side


      [​IMG]
      Passenger side of intake

      After seeing this intake, I understand why a lot of things I'd read indicated that people noticed an increase in power/fuel efficiency after making this repair. It is amazing to me that this vehicle even ran as well as it did with the intake in this condition!


      [​IMG]
      New intake is installed and bolted in. Note that the new part has a map with it indicating the order in which the bolts should be torqued to 25 ft-lbs. Also note that I transferred over the coolant connections on the aluminum portion and installed them with red RTV.


      [​IMG]
      This is just prior to re-installation of the fuel rail on the driver's side. While you're in there you might as well take a close look at your injectors while you've got them out to look for cracking or other damage. Notice that the two injectors in the middle are missing the blue o-ring on the bottom. Some of them stuck in the top of the old intake when they were removed so make sure you fish them out of there. Sometimes the actual fuel rail will separate from the injector and the injector will stick in the intake. No big deal on that either, just make sure the o-ring is still in place and clip it back together once you get the whole fuel rail off. You can also but a kit of 4 o-rings for $3.50 at O'Reilly so if you lose a few (hopefully not down in the cylinder!!!!!) or have a few which are damaged it is no big deal to replace them. I replaced these two with the originals after I picked them out of the old intake.



      Once you have gotten to the point of installing the new intake, re-assembly is pretty straightforward because you're just working backwards to re-install everything. When re-installing the fuel rail, make sure you press the injectors down firmly into the new intake so that the o-rings will seat the injectors and THEN tighten the fuel rail mounting bolts onto the new intake. THEN re-connect the fuel line to the fuel rail.

      After you've got everything buttoned up, get a bright flashlight and carefully inspect all of the COP and spark plug connections and inspect the fuel rails to make sure there is NO movement at all when you wiggle them. Carefully inspect the back (firewall) side of the throttle body to make sure you reconnected all electrical and vacuum line connections.

      After you re-start the vehicle (don't forgot the fuel pump relay/fuse(s)!!!) use the flashlight to make absolutely sure that you do not have any fuel leaks around the fuel rail or injectors. Also make sure that you don't have any coolant leaks coming from either the thermostat housing or anywhere around the top of the engine.
       
      Last edited: July 3, 2012
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    3. kworonowski

      kworonowski Member

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      Excellent write up wish i'd seen it last week. :( Was having timing chains and all the plastic replaced. Will be another plastic thing i'll have to replace in the near future. :thumbsup:
       
    4. JoshMcMadMac

      JoshMcMadMac Well-Known Member

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      Well done! Way to take an issue and turn it into a benefit for the entire community. :cool:
       
    5. SyberTiger

      SyberTiger Active Member

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      Great writeup! There are going to be A LOT OF FOLKS who will appreciate your effort to document this process. Could you tell us how long this job is expected to take?
       
    6. pet575

      pet575 Active Member

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      Thanks! This forum has saved me so much time and money I figure I owe.

      I've heard anywhere from 6-8 hours. Dealer will tell you it is about a $1,400 job, including labor. Getting it apart took about 3.5 hours total. It went faster than that getting it all back together. Cleanup wasn't really much more than about 20 minutes. I went a little slower putting it back together because I was taking pictures and doing a few unrelated things around the house.

      I'd guess that you could do it in less than 6 hours with the info in this thread. Some of the 3.5 hours was stopping to look something up on the internet to make sure I didn't break a piece (like PCV hose connectors) or spray fuel everywhere.
       
    7. SyberTiger

      SyberTiger Active Member

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      Any chance you can post all the pertinent torque numbers for the various bolts? Thanks in advance.
       
    8. pet575

      pet575 Active Member

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      I didn't have access to that and I don't have them for anything but the intake mounting bolts. They were 25 ft-lbs. That was the only thing I used the torque wrench for. The throttle body had 5 bolts and the fuel rail/line is held down by 5 bolts total. The thermostat housing bolts, spark plugs, and alternator bolts/nuts were the only other thing I even put a socket on. I just went by feel on all of those things based on my experience as to how difficult they were to remove (they weren't) and was careful not to overtighten.
       
    9. JoshMcMadMac

      JoshMcMadMac Well-Known Member

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      I think AutoZone has "free" online manuals, which should get you torque valves.
       
    10. kcwebguy

      kcwebguy New Member

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      Excellent post. I am preparing for this exact procedure and will be standing on the shoulders of giants (you) as I tackle it.

      Thanks much for the documentation.
       
    11. chopperb

      chopperb Member

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      Done many of these on crown vics.
       
    12. 20EddieBauer02

      20EddieBauer02 New Member

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      Old thread I know, but I'm getting ready to tackle this same deal on my explorer with 120k on it. The car is cherry and the better half has always babied it, which made me wonder why it broke. In the OP's first pic mine is broken in the same spot causing coolant to leak in the #5 coil pack giving me a misfire after it runs a bit.

      I ordered my intake from am-auto.com, it's supposed to be "upgraded", but I noticed alot of them I looked at weren't for PCV heated 4.6's and mine has one. The one I ordered showed in the pic that it was for a PCV heated 4.6.
      My question is that if it IS NOT for the heated PCV ones, can I just swap my coolant bridge and be good to go? Also besides Injector o-rings will I need any other seals or gaskets? Thanks in advance.
       
    13. HiImBrian

      HiImBrian Well-Known Member

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      I just did mine as well. You need intake manifold gaskets, an upper intake plenum gasket and it would also be a good time to change your spark plugs and replace the coil boots on the coils. I'm posting a detailed how-to on this replacement tomorrow. Look in the modified section.
       
    14. 20EddieBauer02

      20EddieBauer02 New Member

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      Thanks for the quick response. I actually had the dealer do the plugs and flush the tranny 1,500 miles ago, I have them do it every 30k. Which makes me wonder their skills now seeing how the antifreeze had just started leaking right before I took it in and I was getting a random misfire code from the coolant in the plug hole. I seen the leak myself and thought a new housing seal would fix it,and had no idea it was running in the hole and I didn't think I'd run into this.

      Is there any particular brand of gaskets I should get? and what is the plenum gasket? for the throttle body? the intake I ordered looked like it had all the gaskets on the intake but I maybe wrong.
       
    15. 20EddieBauer02

      20EddieBauer02 New Member

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    16. HiImBrian

      HiImBrian Well-Known Member

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      I buy Fel-Pro gaskets and have been happy with them so far. The upper plenum is what bolts to the top of the intake manifold. The gasket is the squareish rubber piece in the top, but it looks like it comes with it. Also wouldn't hurt to pick up new o-rings for your fuel injectors. New coil boots would help keep your plugs dry should you get coolant or water in there again.
       
    17. esclamada

      esclamada Active Member

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      Those come with gaskets built in (just like the Dorman replacement) You don't need to buy separate gaskets. Don't even try putting gasket on top of gasket :)
      You need to buy new o-rings for the injectors.

      -----------------------------------------------------------
      MY MOUNTY
      http://www.facebook.com/diyfordexplorer/photos_albums
       
    18. yglide123

      yglide123 Member

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      Does anyone know if the dorman intake (as described in this post) also requires a gasket? It wasn't mentioned above, but I was under the impression that you would need one - maybe the dorman part comes with it?. I'm ordering parts and want to make sure I get everything.... Thanks
       
    19. esclamada

      esclamada Active Member

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    20. 20EddieBauer02

      20EddieBauer02 New Member

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      Good deal, I just wanted to be sure. Thanks guys. I've done all the work to my chevy but haven't touched this explorer, of coarse there's been no need to, as I haven't had any trouble other than the rear end, that the dealer replaced when I bought it and it started making noise 40k miles later. I pulled it and turned out to be the crush sleeve. Other than changing drive line oils and the motor oil this rides been very reliable til now.
      I never thought it would have had a plastic intake on it, it makes no sense to me, but seems like a straight forward replacement.
       
    21. 20EddieBauer02

      20EddieBauer02 New Member

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      Finished up last night, wow these things are easy to work on compared to a diesel. took about 3.5 hrs. total working wise and I spent probly 4 cleaning the motor, and the other bolt ons. Great post OP and thanks for the replies guys.
       
    22. Licklog

      Licklog New Member

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      FYI

      Have the same issue with my 2002 Explorer. Called my local dealer and he quoted $225 for labor plus parts. The parts dept quoted me $400 for the intake. So $625 plus coolant. The service mgr said the labor price holds even if I buy the parts but then there is no warranty. So with the Doorman part it would be $225 plus about $160 for the intake. Plus coolant. So maybe $400 total

      Called a local top independent and they quoted $550 incl coolant with their parts.

      For $225 it might be worth it to have a Ford mechanic do it.
       
    23. jayton

      jayton Active Member

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      Excellent post with great pictures.

      I chose to go with the OEM intake, as I read a lot of bad things about the Dorman intake on several other forums, not sure if I'm allowed to mention which.
      I got it for $184 at this link:
      http://www.gefracing.com/index.php?act=show_part_datail&part_id=590

      I would love to get one of these all aluminum intakes some day, as I am starting to build a collection of busted 4.6L SOHC intakes. http://amzn.com/B001R1UB0U

      I would also like to suggest that this is also a great time for soaking your injectors overnight and then blowing them out: http://oldfuelinjection.com/?p=82
       
    24. rocco123

      rocco123 Active Member

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      This post seems to be installing 615-175 dorman part yet it has the nipple for the pcv heat. Dorman states 615-175 does not have pcv valve heat. What it the deal here? Mine is leaking and has the nipple beside the thermostat. Does 615-175 work then?
       
      Last edited: July 8, 2014
    25. DickyDanger

      DickyDanger Member

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      would bad plenum gaskets cause skipping or a misfire? i have oil seeping into two of my spark plug holes and it isnt from the valve covers around 2000rpm my montaineer hesitates and skips while going up hill on light throttle i already changed the air and fuel filters and all the spark plugs and coils
       
    26. Keyz4.6l

      Keyz4.6l New Member

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      just curious why does dorman/amazon 615-175 says this dosnt fit 2003 explorer v8 4.6l?
       

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