How to replace upper intake manifold gaskets

You said "The new Felpro did not have the silicon bead like the original" I just bought the same kit and the gasket is black not green and looks plastic not paper is this the one that you got?

someone clear something up for me please. you insert the black rubber looking gaskets into the plenum and then also put the paper gasket down over the manifold? so its like a gasket sitting on a gasket?

Nope, just the flexible gaskets go into the grooves in the plenum. The paper/fiber gasket goes between the fuel rail (aluminum, mates with the plenum, holds the injectors) and the intake manifold. You remove the studs with a Torx socket to release the fuel rail. See my earlier comments on that from 11/09.

Since getting it back together last fall, I threw the same 171 code again this spring and was afraid maybe a stud had snapped. It hadn't, but what I did first was loosen the nuts on the plenum again, and re-torque the studs, then re-torque the nuts. Knock on wood, but I haven't thrown any codes since.

One thing I'd recommend, tho, is getting a set of studs before reassembly. As much as people have trouble with them, it's worth the peace of mind.

Oh, and look at all the pix on this thread. The ones from late Nov don't look like a 4.0 motor.

Good luck!

P0171 and P0174 codes - rough idle

I just completed the first half of a 1500 mile trip.
About 75 miles prior to my destination, my 1999 Ford Explorer (4.0L, OHV engine - 105k miles) showed signs of running rough at idle, after starting it following a brief stop.

A few miles down the road, the Check Engine Light (CEL) comes on but the vehicle continues to run so I keep going. I get to my destination without any problems but at idle, the vehicles idle is surging a little but not stalling.

The next day, I took it to Advance Auto and had the code read. The code was a P0171 and another code indicating the upper hose for the DPFE was either disconnected or blocked. I looked at the hoses for the DPFE and sure enough it was off completely. When I went to reconnect it, I saw why it was off - the nipple that the hose connects to the DPFE was missing and the hose where it attached too was completely cracked and brittle. The hose, with hot gases coming out of it, had actually started to melt some of the plastic insulation around one of the AC lines. I bought a new DPFE and vacuum hoses and attached them (by the way, the vacuum hoses that came off appeared to be reinforced within the middle, like a fuel hose. I put on regular vacuum hoses - is that strong enough for the DPFE or should I have used fuel line hose instead???). The vehicles idle problems did not go away. I also got some MAF cleaner and cleaned the MAF sensor. Still no fix. I also cleaned out the Idle Air Control (IAC) valve as well.

I unplugged the battery and erased the codes from the CEL.

I drove it around, hoping it would throw a code - It finally did and I got the dreaded P0171 and P0174 codes. (BTW, about a month ago, I had a P0171 or 0174 only code (I forgot which one exactly) and changed the passenger side O2 sensor, reset the battery and and CEL went away)

After reading this thread, I sprayed some Carburetor Cleaner in the general area of the upper intake plenum and heard some surging in the engine as I sprayed in different areas (toward the front end of the plenum). Here's some video's of that spraying:

YouTube Video 1 of Carb Cleaner spraying

YouTube Video 2 of Carb Cleaner spraying



I also noticed a long (18") thick rubber vacuum hose that goes from the front of the plenum to an area under the battery. That vacuum hose appears is very chalky and leaves a black powdery mess on your hands when handling it. I am off to replace that this afternoon.

Does anyone have any ideas on the video? Am I looking toward a upper intake plenum gasket leak? Could it just be a fuel injector O ring leak possibly? I can get it smoke tested for $45 but I'm not sure that would be conclusive???

thanks cayman.

jrl, i know for sure i need the new gaskets because i can hear the vaccum leak. i can hear it sucking at idle and i can hear it whistle when accelerating. i have a shaky idle but not super bad, and have jerking and stuttering and hesitation with certain amounts of throttle. not CEL tho, i had one but tightened down the plenum and it went away. its driveable and reliable, but does not have all of its power and the gas mileage is poor.

my CEL was P0171 and 0174, but like i said its not on now. for a long time i had the CEL with no driveability issues and normal gas mileage. then i put in some spark plugs that were not the suggested kinda, and i didnt have a gapper so they are not gapped, so im going to try gapping them and replace the gaskets, if any problems persist after that new plugs are goin in. the suggested kind, lol.

anyways, in the vids it looked like a vac leak. any rpm change with the spraying indicates that. be careful with that spray, it eats up rubber and foam stuff pretty bad. better to spray water or something.

I went and purchased the Felpro Gasket Set, MS 90732.





It came with 3 different items in it:

3 pliable rubber gaskets:



A hard thick gasket (is this what is referred to as the paper gasket? It does not seem paper to me...it's about a 1/4" thick and hard)



and 1 O-Ring




The original poster never mentions the hard, thick gasket? He only discusses the 3 rubber, pliable gaskets.

Also, he does not talk about the O-ring...I know others have mentioned it. I'll go back and re-read those sections.


Question...

After I take off the six 1/2" nuts that holds the plastic plenum cover down, where does the harder, thicker gasket come into play? Is this where the external Torx sockets are needed to take off the six Torx bolts? Is this what is referred to above as the paper gasket??


I don't seem to understand how all these gaskets go back together with the exception of the three rubber pliable ones in the picture. I'll try to document myself when I tackle this job tomorrow.

Oh, I also bought a new EGR valve (w/gasket) to replace that as well since I'll be in the area - it was looking kinda rusted and figured it would need to replaced soon anyway.

with the plenum off the next piece of metal is the fuel rail, that "paper" gasket goes under there.

when going to take off the egr tube, there is a nut that holds the oil dispstick tube in place, remove that and pull that little bracket up over the bolt, under that bracket is another nut to remove that will release the egr tube. took me a minute to find this but its not too hard. you will need a deep well 13mm socket.

back to the fuel rail, i just took my plenum off and i figured i should replace the "paper" gasket as well since im in there. i was wondering if when this is removed if the fuel injectors will be able to be removed? and if i will need new O-rings for the injectors? should i replace them just for the heck of it since im there?

i would also like to clean them and would love some suggestions on how to do that, cheaply, and in my garage.

oh and i also dont know what to do with that O ring.

Hole in Plenum

Today, I finally got to taking off the upper intake plenum.

First, just like everyone else, I must add...I would like to kill the engineer who designed that EGR pipe that runs from the EGR to the underside of the plenum! I spent more time wrestling with that EGR tube than the actual job itself.



Here's my plenum covers taken off:











Here's pics of the underside of the plenum cover:





The front plenum gasket:



The middle plenum gasket:



The back plenum gasket:




Here is a view from the side of the plenum to see how flattened the gaskets are:







Now, my problem was probably not from the plenum gaskets themselves being flattened as opposed to sticking up a little like they are supposed to from the 1st post...but instead, I found my vacuum leak :scratch:

It was this nice hole near the EGR tube that I found.





It was probably caused when the DPFE failed, which in turn caused one of the vacuum hoses to fail, and thus the hose probably rested on the underside of the plenum. It probably looked like BP's underwater oil leak, pushing hot EGR gases onto one spot of the plenum's underside. The actual hole within the melted outer hole was about the size of a .22 bullet. I could not believe that this hole didn't stop my vehicle completely or that I did not hear the sucking in of the extra oxygen.

Now, I know why, when I sprayed carburetor cleaner near the DPFE that the engine raced some. I was thinking there was a leak in the gasket down below and there was a vacuum leak down there somewhere...I just could not figure out where.

Because I could not go to a junk yard today to pull another plenum, I went ahead and mixed some two-part plastic steel epoxy (1 hour cure time - up to 500 degrees rating) and filled in the hole nicely and made a nice patch.

Sorry I don't have any other pictures to post of the repair, my camera ran out of batteries at that point.


I did not bother to go any deeper down into the engine and replace that other thicker gasket under (what I guess is called the fuel rail - don't look like a fuel rail to me???). At that point, I figured I did not want to chance breaking any of those torx bolts, plus, I knew I was looking at a mess trying to line that EGR tube back up. I did replace the three rubber/plastic plenum gaskets though.

Thanks to this forum...many years later after its original posting - you helped my take on this job...even if it was probably not my problem to begin with but greatly assisted in finding my problem.

I'm going to let the repair cure overnight before taking it for a drive...but so far the engine's idle is just as smooth as before.

I wonder how many other defective DPFE's have taken out a plenum???

Here's a pic of my plenum repair that was caused when the DPFE failed and thus caused one of the EGR hoses to fail and spray hot gases directly under the plenum...giving me P0171 and P0174 codes:











Here's a pic of the bad DPFE that caused all of this...

can your plenum gaskets be messed up without throwing a code? I have a rough idle when cold and read on here under a different topic that the bad gaskets will expand when the truck is warmed up and the truck will run fine. This is what mine does but no CEL.

Just reading through this b/c I am about to do the valve covers on my 99 OHV - what a cluster F! I suppose it's a good thing the valve cover gasket comes with the new upper intake gasket kit - as I have a CEL too anyways.

jlrohio:
Any status update on the poly filler you used? how much was a new DPFE assy?

Also wanted to say thanks tot he many great contributions here ESPECIALLY with regards to the PITA EGR tube assy.

Thanks,
Mike

how the HECK!?

So I started to tackle this valve covers this morning. I have read through this a few times and I am really still having the worst time with this EGR tube that goes into the plenum.




I can't get it to budge... Should I just be able to pull the plenum straight up?

-Thanks,
Mike

Torque settings the same for a 4.0 SOHC?

Gents,
are the torque settings and the order of tightening the same for the 4.0 SOHC in the 2 Dr Explorer sport? I see this write up is for the Ranger 4.0 OHV.

hi
does anybody got any picture of a 1997 ford explorer 4.0 ohv v-6 with valve cover off
thank you

Replaced these about two weeks ago now, the CEL (P0171, P0174, both banks lean) has not returned (knocks wood) and the we sprayed "starting fluid" around the upper manifold and vacuum hoses before starting the job and felt we ID'd the leaking area as the rt front nearest you when you stand in front of the truck looking in at the engine. 4 hr job for novices like us. Bear getting the rear bolts off the plenum, bit of wrestling getting the whole thing out. I hope we are fixed.

excellent write-up

ragajungle said:

So I started to tackle this valve covers this morning. I have read through this a few times and I am really still having the worst time with this EGR tube that goes into the plenum.

I can't get it to budge... Should I just be able to pull the plenum straight up?

-Thanks,
Mike

Click to expand...

Try this: http://www.explorerforum.com/forums/showthread.php?t=145716

jlrohio said:

Here's a pic of my plenum repair that was caused when the DPFE failed and thus caused one of the EGR hoses to fail and spray hot gases directly under the plenum...giving me P0171 and P0174 codes:

Here's a pic of the bad DPFE that caused all of this...

Click to expand...

you need cats, which cause the dpfe and manifold to melt....

and im aware this is a 5 months old bump....

one question where did that vacuum line came from