How to replace upper intake manifold gaskets

Dazzlin' Dave · December 4, 2014

Blue/Black RTV

I used the blue stuff (sensor safe) for the intake ports and along the valley where it would come into contact with oil I used the oil safe black stuff. Made sense...

azvampyre · December 17, 2014

If anyone has the fuel rail stud bolts for sale, please pm me.

Edit: Found the only remaining studs at a Ford dealership in MD. $1.50 each.

azvampyre · December 18, 2014

The Felpro gasket set for the OHV is half assed. Ford recalled the upper rubber gaskets and replaced them with much thicker ones, while removing the paper gasket on top of the fuel rail, then the thick paper gasket under the fuel rail had two extra paper gaskets sandwiched on top and bottom with the silicon rings to make up for thickness and leaking over time, but Felpro kept the original thickness of the ring gaskets and removed the thin paper gasket from the kit, making it less than useless. If you buy the Felpro gaskets, youll need to use the ms90732 kit and the thin paper gaskets(2) from the ms90732 kit sandwiched top and bottom of the thick paper gasket under the fuel rail, or just buy the Magnum kit which is the upgraded Ford version. Three rubber gaskets and the thick paper gasket at proper thickness.
Using the Felpro ms90732 will cause it to go bad again in a few years since its out of spec. ms18048 is the updated part for the OHV engine. The problem with the Felpro kits is both the old stock and updated kits use ms90732 part number so it's a crap shoot getting the proper upper set.

Also, my gaskets were fine since I had an engine rebuilt and the updated gaskets were used, but the cel codes were being caused by the egr tube o-ring not sealing. It did as the intake and would swell when warm and cause the rough idling, high idle to smooth out until it could no longer swell enough, then I got rough running constantly until replacing that o-ring.

The thick paper gasket was a Felpro 90732 with the two silicon gaskets made from MP-15?(only text on it)

Code:

MP-15; Hi-Performance short strand synthetic fiber with high ruber content alows for excellent
flex-abilty and low flange presure seal-abilty. This material reduces fluid wicking compared
to celulose fiber materials. High compresive strength greatly reduces extrusion, shear
and tensile strain and exhibits excelent bolt orque retention. Non Stick designation has an
easy release coating on both faces of the gasketing material reduces tearing for frequently removed
items. With an above average intermitent emperature rating of 40˚F this is a very
versatile material for many aplications.

cycle61 · March 22, 2015

azvampyre said:
The Felpro gasket set for the OHV is half assed. Ford recalled the upper rubber gaskets and replaced them with much thicker ones, while removing the paper gasket on top of the fuel rail, then the thick paper gasket under the fuel rail had two extra paper gaskets sandwiched on top and bottom with the silicon rings to make up for thickness and leaking over time, but Felpro kept the original thickness of the ring gaskets and removed the thin paper gasket from the kit, making it less than useless. If you buy the Felpro gaskets, youll need to use the ms90732 kit and the thin paper gaskets(2) from the ms90732 kit sandwiched top and bottom of the thick paper gasket under the fuel rail, or just buy the Magnum kit which is the upgraded Ford version. Three rubber gaskets and the thick paper gasket at proper thickness.
Using the Felpro ms90732 will cause it to go bad again in a few years since its out of spec. ms18048 is the updated part for the OHV engine. The problem with the Felpro kits is both the old stock and updated kits use ms90732 part number so it's a crap shoot getting the proper upper set.

Also, my gaskets were fine since I had an engine rebuilt and the updated gaskets were used, but the cel codes were being caused by the egr tube o-ring not sealing. It did as the intake and would swell when warm and cause the rough idling, high idle to smooth out until it could no longer swell enough, then I got rough running constantly until replacing that o-ring.

Well crap, I just did my upper gaskets today with the Fel-pro kit, based on the original post. Was going to keep digging and replace the lower, but got called into work and had to reassemble quickly. Good to know about the changed spec/part numbers, I'll definitely keep this post handy for reference in the future.

Also, the inside of my intake plenum was absolutely filthy. Black greasy sooty etc. I suspect my EGR valve may be leaking by or stuck open. Combine that with an intake vacuum leak causing a couple cylinders to run rich, make any sense?

4.0blue98 · March 31, 2015

I used this set:

https://www.rockauto.com/catalog/moreinfo.php?pk=2646770&jnid=2&jpid=0

No problems two years latter. My intake plenum looked like crap too. Just like described above. I'll also have to keep that EGR tube O-ring in mind for the future. Mine was a pain to remove so a leak there may be in my future.

jramsey_87 · October 11, 2015

Is it OK to use the gasket that doesn't have the Silicon bead on it or do I need to find one that has it

ohiomotoxer · December 3, 2015

I know this is an ancient thread but I did look it over before doing my 1999 ranger with 103K on the clock.

Here is what I suggest you do BEFORE you start throwing parts at the machine.

) Remove the intake/airbox to throttle body hose.
) Somewhere in said intake hose there should be a smaller rubber hose, mine went to the oil filler neck, remove such hose.
) Find a suitable device to cap off the intake to throttle body hose and tighten the hose clamp, it doesnt need to be super air tight, I used a small container lid.
) Remove the black cap on the IAC valve assembly, it just pulls off.
NOTE this cap is a breather and is also the cause of the fog horn sound you sometimes get. Inside said cap is a little filter, you can pull the cap apart and remove said filter, it just snaps apart.
) now get some dish washing soap, water and a spray bottle, mix the wash soap heavy.
) spray everything associated with the upper intake plenum, ALL hoses, anything rubber AND spray the soap to wherever said hoses lead to.
EXAMPLE: plenum to PCV valve hose, the pcv valve to valve cover insert. Plenum to brake booster hose.
You get the idea, spray everything heavy, also spray the WHOLE INTAKE PLENUM.
) Now purse your lips onto that smaller hose in the intake to throttle body hose WHILE COVERING THE PORT ON THE IAC WHERE YOU REMOVED THE BREATHER CAP and blow for at least 15 seconds.
) With a good light source look over the assembly for bubbles.
) I had bubbles at the pvc hose to the plenum, which I added a hose clamp to that hose.

STEP TWO:
) With bubbles or no bubbles noted move onto the plenum to fuel rail to intake manifold area.
) Remove the coil pack bolts (4) and move it aside.
) Spray the plenum to lower manifold area with soap, it will be a bit hard to get to the under side of the top plenum on the driver side but spray it in there.
) Again purse your lips and blow, dont forget to cap off the IAC breather with your finger for another 15 seconds.
) If you see bubbles at the plenum to manifold joint congrats, now you need to remove and replace.

Here is where you see if you feel lucky punk, well do ya?
MOST backyard mechanics will only replace the plenum to fuel rail gasket which MAY cure the leak.
The 4 rubber gaskets that live in the plenum are weak once they get old and MAY cure your issue but there IS more.

Once you remove the plenum you are looking at the plenum studs and they secure the fuel rail to the actual intake manifold, removing the fuel rail is a more complicated step some backyard mechanics may not have the experience to do.
It isnt rocket science but care and experience IS needed to move on.

Removing the fuel rail leads to injectors that come out and O rings that need replacing not to mention everything in the area MUST BE OPERATING ROOM CLEAN.

Experienced enough to move on? OK
) Remove the fuel rail studs, if you have a 1/4 socket set you may find a socket that works.

) Using a suitable device LIGHTLY pry the fuel rail from the intake manifold, LIGHTLY.

) Remove the fuel rail by unscrewing the fuel supply line.
Remove the sandwich of paper gasket, spacer and paper gasket from the intake manifold.

) Move the plenum and fuel rail to your bench for cleaning and R&R of the rubber gaskets.

I DO SUGGEST YOU DO IT RIGHT AND FIND A KIT WITH UPPER AND LOWER O RINGS, at this point only replacing the upper O rings is futile.

Clean everything up and re assemble using the new thick gasket in place of the old paper/spacer/paper one between the fuel rail and intake manifold.

) Replace the injector O rings and oil them up so that when you introduce the fuel rail they will seat in easily. TAKE YOUR TIME to align the injectors to their perspective port in the fuel rail and use light pressure to push down on the fuel rail until it seats with the manifold, making sure each injector is seated in the fuel rail.

Re assemble and for giggles re apply the soapy mixture and re pressurize the plenum, no more bubbles Bubba? CONGRATS you are now versed in vacuum leaks.

MikeRun · December 11, 2015

Torque wrench

You mention that you need a inch pound torqu wrench, but when you torque the studs and nuts when re-installing the manifold use torque in ft. lbs. what is the inc pound torque wrench for?
Thanks for the write up it was great.:exp:

Hdudic · February 28, 2016

Gasket replacement

I had the same issue on 99 explorer OHV. 2 codes and rough idle, no power, hard start when cold. Replaced both gaskets using these part numbers (I called Ford, they were unsure about the fuel rail gasket, guy at the dealer said there were 2 options) I just bought these bellow

Plenum gaskets(3 of them in a set) F57Z-9E436-AA
Fuel rai gasket F6TZ-9E436-C

It took 2 of us few hours with few Autozone and food runs. We used this guide and one more from this website to familiarize our selfs on how not to screw this up. Thank you for the original write up.
EGR tube is the biggest pain. We pried ours with a round stock and tapped on the plannum. It popped right off. We did spray some WD40 ahead of time. Inside of the plannum was dirty and full of carbon/oil. Same for intake ports. Carb cleaner helped. Be careful not to get too much crap in there as some of the buildup was carbon and some was oily/sticky substance. Valves looked ok and not much carbon build up. Injectors looked horrible. I soaked them for 2 hours in carb cleaner and kerosene. Replaced o-rings on Injectors. Lubed them before assembling everything together. The plannum gasket was totally flat and hard, assuming that was my issue. The lower gasket was the same as what I ordered so I got lucky. That one looked fine but I replaced it any way. Replaced PCV and I would recommend replacing valve cover gaskets and ECT. those would be impossible to replace once all is put together. Cleaned IAC and throttle body. Both somewhat dirty...
Truck started as never before. I was surprised. Expectation was it will crank for minutes before starting.

Now, I don't have check engine any more and it has more power. Idle is still bit rough. Starts good no issues. Fuel consumption still high. I get ~ 200miles per tank. Not sure what else can be done. Hope this helps.

Pics:
https://onedrive.live.com/redir?resid=5EFA3F55E8593C7E!3837&authkey=!ACgRTgZPhZ8LnDM&ithint=folder,

5parky · April 4, 2016

Teddy B

Replacing the gaskets on a 2000 explorer sport SOHC is almost identical. Not sure if he mentioned this but make sure follow torque sequences for removal and installation.

Sailor_D · April 6, 2016

rough idle after replacing upper intake gasket, and guess what ...

First, thanks to Kaiser and others for providing excellent write-ups on the repair job. I'm driving a 98 explorer 4.0 OHV, all stock, and the damn CEL came on with the codes P1151 (sensor1 bank2 lack of switching), P0153 (sensor1, bank2 slow response), P0174 (Bank2 too lean). Reluctantly I purchased a new O2 sensor, thinking I would see Bank1 problems as well in case of a vacuum leak. Not so! The new sensor didn't fix it! BTW, there were no noticeable driving issues, but the wife insisted to fix it. So, I went ahead ordered a gasket set, upper rubber gasket 3pcs, lower gasket and EGR pipe gasket, kind of green O-ring, on Amazon. Also got the EGR valve gasket from the ford dealer, all for a total of $28. Indeed, after removing the upper intake manifold, I noticed the rubber seals were squashed, so put the new ones in, retorqued the studs to 120 in lbs and put everything back together (so I thought), including new o-ring and gasket for the EGR. Did not change the lower intake gasket, it's a pretty hefty one and I have a hard time to see that fail. Started the engine and had a very rough idle. Read in the forum that the onboard computer had to relearn after battery disconnect, but the problem persisted. I believe now that statement is only true with an extremely dirty throttle body, in which case the computer settings are offset from the default factory settings by a lot to make the engine idle smoothly. So here it is - forgot to reconnect the vacuum hose underneath throttle body, see pic. After connecting it the truck immediately idled perfectly at about 750rpm. Long story, but wanted to share this in case somewhat is making a similar mistake

.

wes_bond · August 18, 2016

Wow guys so this is my first post. What an awesome bunch of information! Went ahead and tackled the removal of everything today. I have a 98 Explorer Ohv 4.0 Man that EGR tube is a PITA! I'm waiting till 7:30a to go pickup the parts so I can put everything back together.. On mine it looked like the o rings were pretty much flatter than a pancake. I also noticed a little bit of a hiss at idle and when turning the truck off. Just a note the dipstick bending trick did work for me and I was able to pull the EGR tube out as one piece. Then by spinning the egr tube around I was able to pop it out of the plenum. Thats definitely where the new green o ring will go! Still deciding whether or not I should do the bottom gasket as well. Ill keep you guys posted!

wes_bond · August 19, 2016

Alrighty! so completed the job in about 1.5 hours. Only did the upper plenum gaskets and the green O ring for the EGR tube. Re assembly was much much more easier. Only bad thing is I hooked up the dam spark plug cables to the coil wrong on my first test drive.. Doh! Took it for a second test drive and I hear a loud pop and super loud hissing when I accelerate. What the crap!? Limp it back home and found the dam EGR Sensor hoses unplugged and one of the EGR Sensor ports damaged. Upon further inspection low and behold one was leaking and wouldn't hold a vacuum anymore. Aha! Quick trip to the Junkyard for a replacement sensor and my truck is running better than ever. Drove it 100+ miles and no check engine light. No hissing and I feel like I have regained some lost power.

I remember reading in this thread that someone else had this same problem with there EGR Sensor. Moral of the story check all your vacuum lines very well when you get these codes. I hear that 90% of the time when you get these two codes paired together its very likely it could be the EGR sensor failing or the hoses connected to the sensor since it is affecting both banks. Oh yeah I almost forgot. I did in fact end up breaking the dam head off of one of the torx bit heads. It was my first time using a torque wrench and I think I was ratcheting with to much pressure and missing the clicks. I learned to go slow with the torque wrench 11lbs Ft-in isnt much. As for the broken Torx head I'll replace it later on down the line if I have to replace the gaskets again. I highly recommend getting a spare set just in case you break one.

All in all I want to thank everyone for sharing their info and advise. It was a super easy job and I couldnt have done it without all your guys help. I am so happy my Explorer is running so great. Thanks guys for all the info!

FYI if you need a new EGR sensor heres a link to one on Amazon $65.78 Prime eligible
or try your local junkyard!

https://www.amazon.com/Motorcraft-D...sr=1-3&keywords=f77e-9j460+ab#customerReviews

Gasket Kit available from rock auto for 8 bucks + Shipping!

http://www.rockauto.com/en/moreinfo.php?pk=446866&cc=1304424&jsn=561

wes_bond · August 20, 2016

Well guys, I hate to say it but the dam CEL came on this morning on the way home from work. No idea what the code is yet but once autozone opens up ill let you guys know the latest.. I guess I may have to change out the lower gasket as well. Double checked all vacuum lines with soapy water and starter fluid and no surges or signs of leaking.

wes_bond · August 20, 2016

Okay so. Got a code for a bad Catalytic Converter p0420. I cleared the computer. Hopefully the code doesnt come back. Im thinking when I accidentally hooked up the spark plug cables in the wrong firing order the 3 cylinder misfire may have messed up the catalytic converter or clogged it. Time will tell. Off to test drive the truck! Good news is it seems the intake manifold gasket is holding well! No Vacuum leaks!

albeegood · March 22, 2017

KaiserM715 said:
I had to replace my upper intake manifold gaskets to fix a vacuum leak that was giving me two engine error codes (P0171 Bank 1 lean and P0174 Bank 2 lean). I have a 2000 Ranger with a 4.0L OHV V6 with the plastic upper intake manifold. I was able to diagnose it as a vacuum leak with help from an engine computer scanner, a few other on vehicle checks and help from other forum members (of course!!). A vacuum leak in this location is a common ailment for these engines.
Here are the supplies / tools that I used:

Fel-Pro plenum gasket kit
--Part No: MS90732, $21.99 at O’Reilly Auto Parts
Blue shop towels
In-lb torque wrench
External torx socket set
Silicone grease
O-ring pick
Various wrenches sockets, extensions, etc.
Channel lock pliers
Flat blade screwdriver

Things to remember:
-Disconnect the battery. Several electrical connectors will be disconnected and reconnected throughout this procedure. In addition, your computer will need to be reset so it can recalibrate without the vacuum leak.
-Don’t force electrical connectors when you disconnect or reconnect them. Most have a catch on them that has to be depressed or slightly pried up to get the connector apart. You don’t want to have to add replacing electrical connectors on your to-do list

The next three steps can be performed in any order, but this is the order I did them in.

Next, from left to right in the picture below, disconnect the vacuum line to the throttle body, the connector to the throttle position sensor (TPS), the connector to the idle air controller (IAC), the vacuum line from the PCV valve, the accessory vacuum line and then the vacuum line to the brake booster (you will have to use the pliers to squeeze the hose clamp together to remove the hose). Remove the wiring harness plug from the support attached to the intake (blue circle) and remove the wiring harness support (green circle).

Remove the plastic cover over the throttle body connection to the throttle and cruise control cables. The throttle cable is shown with the red spring and connector. The cruise control cable is black with the red cap. Next, loosen the hose clamp from the intake air tube to the throttle body and disconnect the tube. The cables attach using a ball and socket type setup (green circle in the pic). Use a flat blade screwdriver to gently pry the cables (socket) off of the throttle body (ball). Remove the cruise control cable from the upper intake (blue circle) and then from the throttle cable. To remove it from the throttle cable, pry it up and then off of the pin on the end of the throttle cable (red circle). Remove the throttle cable from the intake. Route both cables out of the way.

I removed the spark plug wires going to cylinders 4-6 (driver’s side) as the wires are threaded through the intake. I disconnected the wire at the spark plug first, then at the coil pack (circled in the photo below) and pulled the spark plug end through the manifold. Remove the four screws that attach the coil pack to the upper intake. Remove the wiring support for the coil pack from the intake (green circle). Go easy on it, I broke mine in the process . Lift off the coil pack and set it aside. I set mine on the passenger side valve cover (refer to the next pic).

Remove the six nuts that hold down the upper intake. Lift the upper intake up and off of the six studs attached to the fuel rail / lower intake. At this point any connections you forgot will become obvious J.

I set the intake on my work bench upside down to replace the gaskets. I am pointing at one of them with my pocket screwdriver. I used a pick to pull the old ones out.

The old gaskets had hardened considerably and were flush with the sealing surface of the upper intake. I can see how this would cause a vacuum leak.

The new gaskets were significantly more pliable and you can see that they protrude below the sealing surface.

I stuffed shop towels in the intake runners of the lower intake (to keep crud from falling in) and cleaned the sealing surface of the fuel rail / lower intake.

I checked the torque on the intake studs using the Ford manual. This is where you need the external Torx sockets and the torque wrench.

Remove the shop towels and lower the intake down over the studs. Tighten the nuts in the order shown below. I used the e-Torx socket to hold the stud and a crow’s foot to tighten the nut.

From here on reassembly is the reverse of disassembly. I used the silicone grease on the connectors for the spark plug wires as well as the socket where the throttle cable connects to the throttle body. Double check all of your wiring and vacuum hose connections, reconnect the battery and then start ‘er up!!

I hope you can help. I first changed my coolant sending unit and upon doing so removed my upper intake and thermostat lid. Put everything back but had a leak at the thermostat lid and my engine ran roughy till my check engine light came on which turned out to be a upper intake leak. So I ordered a complete thermostat housing thermostat and all and felpo air intake gasket kit. Redid everything, have no water leak no check engine light but one out of every 10-15 starts it starts and feels like it's running out of gas. I have to turn it off and restart for it to start good. After starting the truck runs fine, it's just the start-up??? I'm starting to think it's something else.

albeegood · March 22, 2017

albeegood said:
I hope you can help. I first changed my coolant sending unit and upon doing so removed my upper intake and thermostat lid. Put everything back but had a leak at the thermostat lid and my engine ran roughy till my check engine light came on which turned out to be a upper intake leak. So I ordered a complete thermostat housing thermostat and all and felpo air intake gasket kit. Redid everything, have no water leak no check engine light but one out of every 10-15 starts it starts and feels like it's running out of gas. I have to turn it off and restart for it to start good. After starting the truck runs fine, it's just the start-up??? I'm starting to think it's something else.

Ps. Can you still have an air intake leak but no check engine light?? Yes my check engine light works. Thx.

WhiteLX · January 3, 2019

What is the correct part number for the good gasket set? I want to replace the upper (plenum) and lower (fuel rail) gaskets. From a previous post, it appears the MS90732 is not good. I was looking at MS15675A, but not sure if that is the updated set. I saw
Magnum MS18048 listed as the good set, but unfortunately it is not available through prime so I wouldn't get it in time for this weekend.

I'm working on a 98 Ranger with the OHV 4.0.

Jessica Pruett · February 1, 2019

WhiteLX said:
What is the correct part number for the good gasket set? I want to replace the upper (plenum) and lower (fuel rail) gaskets. From a previous post, it appears the MS90732 is not good. I was looking at MS15675A, but not sure if that is the updated set. I saw
Magnum MS18048 listed as the good set, but unfortunately it is not available through prime so I wouldn't get it in time for this weekend.

I'm working on a 98 Ranger with the OHV 4.0.

Rock Auto sells a gasket kit with egr o ring both valve cover gaskets and lower intake gaskets upper gasket and fuel rail gasket. Just enter your vehicle info. They have never provided me with the wrong part. Except the exhaust manifold studs. They have those listed as a M10x1.50, however the heads only accept a M8x1.25 stud. Good luck it's a pretty easy job to do a top end gasket set .

How to replace upper intake manifold gaskets

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