94 Explorer Intake maintenance

I have been having an issue with spark knock...actually
pinging on my 94 EB Explorer for some time now. Here is what has been
happening to my explorer.



Over the last year I have had to add coolant to the system every 1 or
2 months as the radiator gets low. There are NO signs of any leaks
anywhere so the usage must be internal.

I have replaced the plugs, new IAC Valve, new TP Sensor, and a host
of other things to keep the engine at top performance and have been
satisfied with the performance.

I have become worried about the coolant usage especially since there
is no outside indicator of a leak.

I am willing to take a couple days off from work in order to replace
gaskets in the intake and possibly the head gaskets depending on what
I find.

At this point I am trying to find out as much info about performing
the task at hand. Any pointers from you guys will be appreciated.
There is no doubt I am going to perform this task because if I do not
I will for sure experience and engine failure. The intervals between
which I have to add coolant are becoming more frequent.

Thanks,

Sam in Raleigh.

>Do you have white smoke when you start it up? From what you said to me it
>sounds like the intake manifold gasket but I would not rule out head gaskets
>either. Does your coolant reservoir boil over when you shut off the engine?
>To me that would indicate a possible head gasket leak.
>
>I suggest you buy a Hayne's manual (or Chilton's) and follow the
>instructions to replace the intake manifold gasket. It's a bit complicated
>(to me anyway). I've done it twice. I labeled everything before
>disconnecting. Make sure you label the spark plug wires as you will need to
>remove the ignition module.
>
>
>Here is a link to Auto Zone's repair info. You have to scroll down to find
>the 4.0 OHV (EFI) engine.
>
>http://www.autozone.com/servlet/UiBr...n_us/0900823d/
>80/0b/94/b0/0900823d800b94b0.jsp
>
>Chances are the link won't work but if you go to autozone.com and enter your
>car info then click on "repair info", "engine", and then "intake manifold"
>it should get you there. I think this info is less than complete but it's
>better than nothing.


No I do not have white smoke when I first start the vehicle and no the
coolant overflow does not boil over when turned off.

The vehicle idles so smooth that it is hard to tell the vehicle is on.
My experience with blown head gaskets is that they have always gone
pretty fast for me......this issue has been going on for about a year
now as it has only been the last month that I have felt the urgency to
get this resolved before my luck runs out.

I mentioned previously how the interval between having to add coolant
got shorter but I must say I may be incorrect as to say that the
interval has gotten shorter...I have just become more aware of it
lately as I feel I have let this problem go long enough.

I have a lot of spark knocking (pinging) that takes place during heavy
acceleration and that coupled with the coolant loss has me worried.
I do not want to drive the vehicle much longer the way it is.

A couple years ago the octane shorting bar was removed because the
previous owner (close friend) complained to his mechanic about
pinging. The mechanic got a bulletin from Ford that told him to
remove that jumper thus pretty much resolving his spark knocking issue
however his performance went down a little.

Here it is 2 or 3 years later and the spark knocking is back. MAF
replaced, throttle body cleaned, sensors replaced, plugs, etc all
replaced....and now the pinging is back. I put the octance shorting
jumper back in yesterday to get some of the performance back and I
have noticed a difference. I just do not accelerate hard as most of
my driving is done around town.

So with all that in mind....I have got to investigate the gaskets. I
should do a compression test but when my car is idling I swear you
cannot tell it is on...so quiet and smooth until the oil gets low I
just do not think I have a cylinder compression problem.

I appreciate you help. What do you think about what I have said?

Sam in Raleigh

> So with all that in mind....I have got to investigate the gaskets. I
> should do a compression test but when my car is idling I swear you
> cannot tell it is on...so quiet and smooth until the oil gets low I
> just do not think I have a cylinder compression problem.
<snip>
Umm. Why does the oil get low? Maybe just a complete overhaul would
take care of both problems?

Just curious,
Mark

WHen I say low I mean a qt low every month or 2. 160k on the engine.

My hope is that I get the intake off and see the problem (intake
gasket). I will take it as it comes. Time is a factor too with a
family and all my time is limited. I will however make the time for
this project however I hope I will not have to take a day off from
work to fix this.

If I get the intake off I might as well go ahead and replace the head
gaskets. Just depends on how things go.

Thanks for your reply.
-Sam
>Umm. Why does the oil get low? Maybe just a complete overhaul would
>take care of both problems?
>
>Just curious,
>Mark

All the symptoms sound like an intake manifold gasket leaking coolant into
the combustion chamber.

On my 1993 Explorer, you could see visible carbon buildup on the #5 spark
plug because that was where the leak was.

The intake manifold gasket is a multipiece gasket, I think, and can leak
where the two pieces come together which is at the #5 cylinder. (This is
from past posts, not personal observation).

Pull the #5 spark plug and take a look at it (and if the coolant is leaking
into the manifold, the plug will be coated white. The #5 plug is middle of
right side I'm pretty sure. Pull the #4 plug and compare the two.

I had this problem and I had good luck with just tightening the intake
manifold bolts (the lower bolts. The don't require much torque (180 inch
pounds is my recollection, but look it up for goodness sake before you
torque them.) The aluminum intake manifolds tend to work loose and the
gasket material will gap and leak.

I tightened my lower bolts and my problem eventually went away. Be very
careful and torque in the correct sequence a few inch pounds at a time or
you'll break the intake manifold which is a relatively thin piece of
aluminum. I had to torque twice about 3 months apart as the bolts worked
loose again.

Now, I check them once a year and seldom have to retorque.

Good luck and hopefully retorquing will fix the problem and you won't have
to replace the intake manifold gaskets. If you do, Ford redesigned the
gasket so the new gasket seals better (again, that's what I've read).



"Sam" > wrote in message
...
> I have been having an issue with spark knock...actually
> pinging on my 94 EB Explorer for some time now. Here is what has been
> happening to my explorer.
>
>
>
> Over the last year I have had to add coolant to the system every 1 or
> 2 months as the radiator gets low. There are NO signs of any leaks
> anywhere so the usage must be internal.
>
> I have replaced the plugs, new IAC Valve, new TP Sensor, and a host
> of other things to keep the engine at top performance and have been
> satisfied with the performance.
>
> I have become worried about the coolant usage especially since there
> is no outside indicator of a leak.
>
> I am willing to take a couple days off from work in order to replace
> gaskets in the intake and possibly the head gaskets depending on what
> I find.
>
> At this point I am trying to find out as much info about performing
> the task at hand. Any pointers from you guys will be appreciated.
> There is no doubt I am going to perform this task because if I do not
> I will for sure experience and engine failure. The intervals between
> which I have to add coolant are becoming more frequent.
>
> Thanks,
>
> Sam in Raleigh.

On Tue, 14 Mar 2006 19:22:12 -0600, "Tommy Wood" >
wrote:

>All the symptoms sound like an intake manifold gasket leaking coolant into
>the combustion chamber.
>
>On my 1993 Explorer, you could see visible carbon buildup on the #5 spark
>plug because that was where the leak was.
>
>The intake manifold gasket is a multipiece gasket, I think, and can leak
>where the two pieces come together which is at the #5 cylinder. (This is
>from past posts, not personal observation).
>
>Pull the #5 spark plug and take a look at it (and if the coolant is leaking
>into the manifold, the plug will be coated white. The #5 plug is middle of
>right side I'm pretty sure. Pull the #4 plug and compare the two.
>
>I had this problem and I had good luck with just tightening the intake
>manifold bolts (the lower bolts. The don't require much torque (180 inch
>pounds is my recollection, but look it up for goodness sake before you
>torque them.) The aluminum intake manifolds tend to work loose and the
>gasket material will gap and leak.
>
>I tightened my lower bolts and my problem eventually went away. Be very
>careful and torque in the correct sequence a few inch pounds at a time or
>you'll break the intake manifold which is a relatively thin piece of
>aluminum. I had to torque twice about 3 months apart as the bolts worked
>loose again.
>
>Now, I check them once a year and seldom have to retorque.
>
>Good luck and hopefully retorquing will fix the problem and you won't have
>to replace the intake manifold gaskets. If you do, Ford redesigned the
>gasket so the new gasket seals better (again, that's what I've read).
>
>

How do you get to the lower intake bolts? If I recall the throttle
body assembly is part of the upper intake assembly so I assume that
one has to take off the upper intake assembly in order to be able to
access the bolts to tighten for the lower intake. Is that correct?

-Sam in Raleigh.

I believe all you have to do is remove the plastic cover off the throttle
body. You do not have to remove any other parts. You need a long extension
(maybe a 6 + 3 inch extension).

If you just remove the plastic cover off the throttle body, then you can see
the bolts if you look down through the maze of intakes and other garbage
going over the engine.

If I remember, Haynes has a diagram of how to tighten the bolts (as in
installation of the manifold).


"Sam" > wrote in message
...
> On Tue, 14 Mar 2006 19:22:12 -0600, "Tommy Wood" >
> wrote:
>
>>All the symptoms sound like an intake manifold gasket leaking coolant into
>>the combustion chamber.
>>
>>On my 1993 Explorer, you could see visible carbon buildup on the #5 spark
>>plug because that was where the leak was.
>>
>>The intake manifold gasket is a multipiece gasket, I think, and can leak
>>where the two pieces come together which is at the #5 cylinder. (This is
>>from past posts, not personal observation).
>>
>>Pull the #5 spark plug and take a look at it (and if the coolant is
>>leaking
>>into the manifold, the plug will be coated white. The #5 plug is middle
>>of
>>right side I'm pretty sure. Pull the #4 plug and compare the two.
>>
>>I had this problem and I had good luck with just tightening the intake
>>manifold bolts (the lower bolts. The don't require much torque (180 inch
>>pounds is my recollection, but look it up for goodness sake before you
>>torque them.) The aluminum intake manifolds tend to work loose and the
>>gasket material will gap and leak.
>>
>>I tightened my lower bolts and my problem eventually went away. Be very
>>careful and torque in the correct sequence a few inch pounds at a time or
>>you'll break the intake manifold which is a relatively thin piece of
>>aluminum. I had to torque twice about 3 months apart as the bolts worked
>>loose again.
>>
>>Now, I check them once a year and seldom have to retorque.
>>
>>Good luck and hopefully retorquing will fix the problem and you won't have
>>to replace the intake manifold gaskets. If you do, Ford redesigned the
>>gasket so the new gasket seals better (again, that's what I've read).
>>
>>
>
> How do you get to the lower intake bolts? If I recall the throttle
> body assembly is part of the upper intake assembly so I assume that
> one has to take off the upper intake assembly in order to be able to
> access the bolts to tighten for the lower intake. Is that correct?
>
> -Sam in Raleigh.

it is impossible for the intake gasket to leak coolant into combustion
chamber on a 4.0 OHV.
if the gasket is leaking it will leak coolant into the valley where it will
mix with the oil

Only a leaking headgasket or cracked head will do that


"Tommy Wood" > wrote in message
...
> All the symptoms sound like an intake manifold gasket leaking coolant into
> the combustion chamber.
>
> On my 1993 Explorer, you could see visible carbon buildup on the #5 spark
> plug because that was where the leak was.
>
> The intake manifold gasket is a multipiece gasket, I think, and can leak
> where the two pieces come together which is at the #5 cylinder. (This is
> from past posts, not personal observation).
>
> Pull the #5 spark plug and take a look at it (and if the coolant is
leaking
> into the manifold, the plug will be coated white. The #5 plug is middle
of
> right side I'm pretty sure. Pull the #4 plug and compare the two.
>
> I had this problem and I had good luck with just tightening the intake
> manifold bolts (the lower bolts. The don't require much torque (180 inch
> pounds is my recollection, but look it up for goodness sake before you
> torque them.) The aluminum intake manifolds tend to work loose and the
> gasket material will gap and leak.
>
> I tightened my lower bolts and my problem eventually went away. Be very
> careful and torque in the correct sequence a few inch pounds at a time or
> you'll break the intake manifold which is a relatively thin piece of
> aluminum. I had to torque twice about 3 months apart as the bolts worked
> loose again.
>
> Now, I check them once a year and seldom have to retorque.
>
> Good luck and hopefully retorquing will fix the problem and you won't have
> to replace the intake manifold gaskets. If you do, Ford redesigned the
> gasket so the new gasket seals better (again, that's what I've read).
>
>
>
> "Sam" > wrote in message
> ...
> > I have been having an issue with spark knock...actually
> > pinging on my 94 EB Explorer for some time now. Here is what has been
> > happening to my explorer.
> >
> >
> >
> > Over the last year I have had to add coolant to the system every 1 or
> > 2 months as the radiator gets low. There are NO signs of any leaks
> > anywhere so the usage must be internal.
> >
> > I have replaced the plugs, new IAC Valve, new TP Sensor, and a host
> > of other things to keep the engine at top performance and have been
> > satisfied with the performance.
> >
> > I have become worried about the coolant usage especially since there
> > is no outside indicator of a leak.
> >
> > I am willing to take a couple days off from work in order to replace
> > gaskets in the intake and possibly the head gaskets depending on what
> > I find.
> >
> > At this point I am trying to find out as much info about performing
> > the task at hand. Any pointers from you guys will be appreciated.
> > There is no doubt I am going to perform this task because if I do not
> > I will for sure experience and engine failure. The intervals between
> > which I have to add coolant are becoming more frequent.
> >
> > Thanks,
> >
> > Sam in Raleigh.
>
>
>

I am not doubting your words....the point of all of this for me to
understand is that the intake leak is the source of my coolant leak.
Where it goes when it leaks I really don't care but I do care to be
sure that a leaking intake gasket is a possible source for my coolant
loss.

I did notice a couple of months ago when I was changing plugs that the
spark plug in the middle on the driver side bank was real moist. I
thought that was odd and figured I had accidently rubbed it on
something moist when removing it. Is that the location for #5
cylinder?

I have a service manual coming today or tomorrow which I hope to be
more informative than the Haynes that I currently have.

I really appreciate everyone helping our here. I will continue to
discuss this until I am fixed and will let you guys know what I find.

Thanks again,

Sam in Raleigh

.....to be continued

On Tue, 14 Mar 2006 21:48:00 -0700, "JohanB"
> wrote:

>it is impossible for the intake gasket to leak coolant into combustion
>chamber on a 4.0 OHV.
>if the gasket is leaking it will leak coolant into the valley where it will
>mix with the oil
>
>Only a leaking headgasket or cracked head will do that
>
>
>"Tommy Wood" > wrote in message
...
>> All the symptoms sound like an intake manifold gasket leaking coolant into
>> the combustion chamber.
>>
>> On my 1993 Explorer, you could see visible carbon buildup on the #5 spark
>> plug because that was where the leak was.
>>
>> The intake manifold gasket is a multipiece gasket, I think, and can leak
>> where the two pieces come together which is at the #5 cylinder. (This is
>> from past posts, not personal observation).
>>
>> Pull the #5 spark plug and take a look at it (and if the coolant is
>leaking
>> into the manifold, the plug will be coated white. The #5 plug is middle
>of
>> right side I'm pretty sure. Pull the #4 plug and compare the two.
>>
>> I had this problem and I had good luck with just tightening the intake
>> manifold bolts (the lower bolts. The don't require much torque (180 inch
>> pounds is my recollection, but look it up for goodness sake before you
>> torque them.) The aluminum intake manifolds tend to work loose and the
>> gasket material will gap and leak.
>>
>> I tightened my lower bolts and my problem eventually went away. Be very
>> careful and torque in the correct sequence a few inch pounds at a time or
>> you'll break the intake manifold which is a relatively thin piece of
>> aluminum. I had to torque twice about 3 months apart as the bolts worked
>> loose again.
>>
>> Now, I check them once a year and seldom have to retorque.
>>
>> Good luck and hopefully retorquing will fix the problem and you won't have
>> to replace the intake manifold gaskets. If you do, Ford redesigned the
>> gasket so the new gasket seals better (again, that's what I've read).
>>
>>
>>
>> "Sam" > wrote in message
>> ...
>> > I have been having an issue with spark knock...actually
>> > pinging on my 94 EB Explorer for some time now. Here is what has been
>> > happening to my explorer.
>> >
>> >
>> >
>> > Over the last year I have had to add coolant to the system every 1 or
>> > 2 months as the radiator gets low. There are NO signs of any leaks
>> > anywhere so the usage must be internal.
>> >
>> > I have replaced the plugs, new IAC Valve, new TP Sensor, and a host
>> > of other things to keep the engine at top performance and have been
>> > satisfied with the performance.
>> >
>> > I have become worried about the coolant usage especially since there
>> > is no outside indicator of a leak.
>> >
>> > I am willing to take a couple days off from work in order to replace
>> > gaskets in the intake and possibly the head gaskets depending on what
>> > I find.
>> >
>> > At this point I am trying to find out as much info about performing
>> > the task at hand. Any pointers from you guys will be appreciated.
>> > There is no doubt I am going to perform this task because if I do not
>> > I will for sure experience and engine failure. The intervals between
>> > which I have to add coolant are becoming more frequent.
>> >
>> > Thanks,
>> >
>> > Sam in Raleigh.
>>
>>
>>
>

"Sam" > wrote in message
...
> I am not doubting your words....the point of all of this for me to
> understand is that the intake leak is the source of my coolant leak.
> Where it goes when it leaks I really don't care but I do care to be
> sure that a leaking intake gasket is a possible source for my coolant
> loss.
>
> I did notice a couple of months ago when I was changing plugs that the
> spark plug in the middle on the driver side bank was real moist. I
> thought that was odd and figured I had accidently rubbed it on
> something moist when removing it. Is that the location for #5
> cylinder?
>
> I have a service manual coming today or tomorrow which I hope to be
> more informative than the Haynes that I currently have.
>
> I really appreciate everyone helping our here. I will continue to
> discuss this until I am fixed and will let you guys know what I find.
>
> Thanks again,
>
> Sam in Raleigh
>
> ....to be continued
>
> On Tue, 14 Mar 2006 21:48:00 -0700, "JohanB"
> > wrote:
>
> >it is impossible for the intake gasket to leak coolant into combustion
> >chamber on a 4.0 OHV.
> >if the gasket is leaking it will leak coolant into the valley where it
will
> >mix with the oil
> >
> >Only a leaking headgasket or cracked head will do that
> >
> >
> >"Tommy Wood" > wrote in message
> ...
> >> All the symptoms sound like an intake manifold gasket leaking coolant
into
> >> the combustion chamber.
> >>
> >> On my 1993 Explorer, you could see visible carbon buildup on the #5
spark
> >> plug because that was where the leak was.
> >>
> >> The intake manifold gasket is a multipiece gasket, I think, and can
leak
> >> where the two pieces come together which is at the #5 cylinder. (This
is
> >> from past posts, not personal observation).
> >>
> >> Pull the #5 spark plug and take a look at it (and if the coolant is
> >leaking
> >> into the manifold, the plug will be coated white. The #5 plug is
middle
> >of
> >> right side I'm pretty sure. Pull the #4 plug and compare the two.
> >>
> >> I had this problem and I had good luck with just tightening the intake
> >> manifold bolts (the lower bolts. The don't require much torque (180
inch
> >> pounds is my recollection, but look it up for goodness sake before you
> >> torque them.) The aluminum intake manifolds tend to work loose and the
> >> gasket material will gap and leak.
> >>
> >> I tightened my lower bolts and my problem eventually went away. Be
very
> >> careful and torque in the correct sequence a few inch pounds at a time
or
> >> you'll break the intake manifold which is a relatively thin piece of
> >> aluminum. I had to torque twice about 3 months apart as the bolts
worked
> >> loose again.
> >>
> >> Now, I check them once a year and seldom have to retorque.
> >>
> >> Good luck and hopefully retorquing will fix the problem and you won't
have
> >> to replace the intake manifold gaskets. If you do, Ford redesigned the
> >> gasket so the new gasket seals better (again, that's what I've read).
> >>
> >>
> >>
> >> "Sam" > wrote in message
> >> ...
> >> > I have been having an issue with spark knock...actually
> >> > pinging on my 94 EB Explorer for some time now. Here is what has
been
> >> > happening to my explorer.
> >> >
> >> >
> >> >
> >> > Over the last year I have had to add coolant to the system every 1 or
> >> > 2 months as the radiator gets low. There are NO signs of any leaks
> >> > anywhere so the usage must be internal.
> >> >
> >> > I have replaced the plugs, new IAC Valve, new TP Sensor, and a host
> >> > of other things to keep the engine at top performance and have been
> >> > satisfied with the performance.
> >> >
> >> > I have become worried about the coolant usage especially since there
> >> > is no outside indicator of a leak.
> >> >
> >> > I am willing to take a couple days off from work in order to replace
> >> > gaskets in the intake and possibly the head gaskets depending on what
> >> > I find.
> >> >
> >> > At this point I am trying to find out as much info about performing
> >> > the task at hand. Any pointers from you guys will be appreciated.
> >> > There is no doubt I am going to perform this task because if I do not
> >> > I will for sure experience and engine failure. The intervals between
> >> > which I have to add coolant are becoming more frequent.
> >> >
> >> > Thanks,
> >> >
> >> > Sam in Raleigh.
> >>
> >>
> >>
> >

I'm not quite understanding what JohanB is saying because I have seen a
coolant leak from the lower intake manifold gasket going into the intake
ports--some were wet inside.

From everything you said it sounds to me like the manifold gasket is your
problem. You could try retorquing it as was suggested and I've read many
accounts of success doing that. It sounds like it's not leaking really bad
yet. Besides that if you did replace the gasket and then determined that
the head gaskets(s) need to be replaced then you would have to remove the
intake manifold again and most likely have to replace the gasket--again.

The tightening sequence is as follows:

3,5,7,2
:-)
1,6,8,4

The smiley is you. #1 is on the front, right, facing the front of the
Explorer.

The bolts/nuts are to be tightened in three steps on a '94:

72 in-lbs
144 in-lbs
192 in-lbs

It's been a while since I've done this but I think you'll have to remove the
upper intake manifold (throttle body) to get at the lower manifold nuts.
Someone who has done the retorque method could tell you better than I can.

I think the Hayne's manual is fine for this job. If you decide to replace
the gasket you'll need some gasket silicone too. I used the blue stuff and
it's holding up fine. One of my gaskets came with some black silicone but
it didn't look like enough to do the job. You need to put a fairly heavy
bead on the "corners" and a thin bead on the water jacket seals. The gasket
is one piece and it folds in two places. The extra sealant goes in those
folds.