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Car Forum / Ford / Ford Explorer / April 200694 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. > 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 [quoted text clipped - 24 lines] > > 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/UiBroker?ForwardPage=/az/cds/en_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. >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 [quoted text clipped - 17 lines] >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 > WHen I say low I mean a qt low every month or 2. 160k on the engine. > [quoted text clipped - 14 lines] > >Just curious, > >Mark OK, that's probably not excessive. Heaven knows I understand the time/cost problem when raising a family. One of my vehicles is a '94 Chevy Astro that has 270,000 miles on it. It still does OK on oil, but I do replace water and transmission fluid on a fairly regular basis. It's a daily driver, but there it has a point where the benefit of major repairs may not be worth the cost. If I could do a headgasket easily I might, but... Mark Well I proceeded to replace the intake manifold and valve cover gaskets today and only got the upper and left side valve cover off. Due to family obligations I had to leave the vehicle in the garage until tomorrow. I thought I would post what I have found so far. I removed the upper intake manifold. When I looked inside the upper intake I noticed there was a puddle of oil. Also most of the inside was very moist with oil. Looking down the throat of the lower intake I see that the ports are moist. I am kind of excited wondering what I will find tomorrow when I remove the lower and the right valve cover. I got to ahead of myself. Once I had the upper and left valve cover off I realized that I had not relieved the fuel pressure. I was upset as I did not read the steps in the Haynes and went ahead at my own progression. Long story short...put the upper back on ...enough to be able to control the air intake so to not run wide open.....disabled the fuel pump by the inertia switch and ran engine until no fuel pressure. So anyway I Sunday will be the big day. Kind of excited knowing I will finally be able to see if the lower intake gasket was the source of my problem or elsewhere. -Sam in Raleigh. > Well I proceeded to replace the intake manifold and valve >cover gaskets today and only got the upper and left side valve cover [quoted text clipped - 6 lines] >with oil. Looking down the throat of the lower intake I see that the >ports are moist. Are you sure it's oil and not transmission fluid? If the vacuum modulator has a leak it will allow tranny fluid to get sucked up into the intake. Eventually you would be low on tranny fluid. >I am kind of excited wondering what I will find tomorrow when I remove >the lower and the right valve cover. [quoted text clipped - 12 lines] > >-Sam in Raleigh. The intake gasket can not only leak coolant but also have a leak from crankcase/valley into intake area causing it to suck up more oil then usual > > Well I proceeded to replace the intake manifold and valve > >cover gaskets today and only got the upper and left side valve cover [quoted text clipped - 27 lines] > > > >-Sam in Raleigh. >Are you sure it's oil and not transmission fluid? If the vacuum >modulator has a leak it will allow tranny fluid to get sucked up into >the intake. Eventually you would be low on tranny fluid. Yes I am sure it is not tranny however, I suspected my modulator was defective several months ago and replaced it. I just got home after test driving my vehicle for 1 hr. I have finally replaced the lower intake manifold gasket, upper intake manifold gasket and the fuel rail manifold gasket. I replaced the valve cover gaskets. I replaced the thermostat and flushed the coolant. I installed new spark plug wires, new platinum spark plugs and a new Coil pack. I installed new fuel injectors. Now for the results.... BOY WHAT A DIFFERENCE. After I got out of the car just now..I noticed that this was the first time in I do not know how long that I have not smelled coolant. You see I was loosing coolant on a regular basis over the last year. I could always smell coolant however none was left on the pavement or anywhere...eaten up internally. When I had the lower intake off I could see the discoloration of the gasket in a few spots where the coolant was flowing. Time will tell if the coolant leak is resolved and I suspect it has been solved. Spark knocking is present every once in a while but not anywhere like it used to be. I might have some bad gas in this tank full and will fill up with from different location tomorrow. Interstate speeds showed performance increase. It is so much easier to maintain a constant speed now and less effort is required to navigate hills, etc. By effort I mean how far and long I have to depress the accelerator cable. The old fuel injectors needed to go. They were very dirty looking and had crud on them..a residue if you will plus some dirt. I guess I could have tried to wet soak them with a couple tank fulls of fuel injector cleaner but the way I saw it was that I was in there so I will make the best of it. Anyway thanks to all who helped. If anything happens I will post an update....anything negative. Sam in Raleigh. >>Are you sure it's oil and not transmission fluid? If the vacuum >>modulator has a leak it will allow tranny fluid to get sucked up into [quoted text clipped - 40 lines] > >Sam in Raleigh. Glad to hear you seem to have it all sorted out. If you haven't tried Techroline Fuel Injector cleaner (Fuel additive) you might give it a try. I've used it in several cars I bought with high mileage and it always seems to help as judged by smoother idling, which is often the sign of dirty injectors producing a poor spray pattern. Congratulations. Whatever doesn't kill ya makes ya stronger. >>Are you sure it's oil and not transmission fluid? If the vacuum >>modulator has a leak it will allow tranny fluid to get sucked up into [quoted text clipped - 40 lines] > > Sam in Raleigh. > >Are you sure it's oil and not transmission fluid? If the vacuum > >modulator has a leak it will allow tranny fluid to get sucked up into [quoted text clipped - 40 lines] > > Sam in Raleigh. Glad to hear it's running good. These engines are notorious for leaking intake manifold gaskets, particularly the lower one. Plus it's awful nice not to have oil leaking from the valve covers all the time. Any particular reason you changed the coil pack? How much did it cost? I don't think I've read about them failing on these engine. So, does your 4WD work? >Any particular reason you changed the coil pack? How much did it cost? I >don't think I've read about them failing on these engine. When I removed the coil pack during intake gasket project I noticed that one of the terminals had a lot of corrosion on it and the spark plugs wire to that particular post had a bunch of corrosion. WHen I say corrosion I mean a bunch of green and white powdery residue. The whole attitude I have had during this has been , "while I am there go ahead and replace it as long as it does not cost too much." I got a discount from a friend at a local autoparts and got it for $69. I do not think it was failing however I just was in one of those spending moods. >So, does your 4WD work? My 4wd does not work because of the automatic hubs. They have been replaced before and have failed again. Cheap parts. I am aware of the manual hubs mod and am debating on whether to spend the money to replace them again or to install manual hubs. The axle spins and all just fine. When I replaced the front rotors, calipers and pads 2 weeks ago I got a chance again to see how cheap the construction of the automatic hubs are again and found myself debating the route I am going to take to fix the issue. Now that the weather here in Raleigh, N.C. is warm again the 4wd issue goes to the back burner again. Fortunately winter this year here was extremely mild and there was never any need for 4wd vehicles. Here is Raleigh that is...not the mountains. > >Any particular reason you changed the coil pack? How much did it cost? I > >don't think I've read about them failing on these engine. [quoted text clipped - 8 lines] > I do not think it was failing however I just was in one of those > spending moods. I would have replaced it too. > >So, does your 4WD work? > [quoted text clipped - 10 lines] > never any need for 4wd vehicles. Here is Raleigh that is...not the > mountains. Just in case you are not familiar the servo motor on the transfer case is another of the common problems on the early Exploders. Usually they just get stuck and need to be taken apart, cleaned real good, and relubed. I have found Vaseline to be very reliable for the little gears inside the servo. There is a fix online somewhere if you are interested for the autohubs but most of us have switched to manual. I'm in sunny Southern California and last year if you didn't have 4WD you didn't go anywhere. This year no 4WD necessary here either. Last year (speaking of servo motors) a Bronco got stuck in the mud and I went to pull it out and my 4WD would not activate so I had to go home and yank off the servo motor and switch the transfer case by hand. The mud was so deep it covered the Bronco's front bumper and it was in 4 Low and couldn't move. >Just in case you are not familiar the servo motor on the transfer case is >another of the common problems on the early Exploders. Usually they just [quoted text clipped - 9 lines] >servo motor and switch the transfer case by hand. The mud was so deep it >covered the Bronco's front bumper and it was in 4 Low and couldn't move. Have you since fixed the servo motor issue? BTW, It has been almost a week since I replaced the intake manifold gaskets, fuel injectors, fuel pressure regulator, thermostat and other various items. Today I replaced the EGR Valve and now I feel pretty good to say that I have spent all the money I want to on this vehicle for a while. Needless to say all is well. The vehicle is behaving so much more like it is supposed to. Sure is nice to feel confident again that all is well with the motor. Who knows...maybe next week the water pump will fail. Oh well. Take it as it comes!! Still better than car payments!! Sam in Raleigh. 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). > 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 [quoted text clipped - 24 lines] > > Sam in Raleigh. >All the symptoms sound like an intake manifold gasket leaking coolant into >the combustion chamber. [quoted text clipped - 27 lines] >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). >>All the symptoms sound like an intake manifold gasket leaking coolant into >>the combustion chamber. [quoted text clipped - 36 lines] > > -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 > All the symptoms sound like an intake manifold gasket leaking coolant into > the combustion chamber. [quoted text clipped - 56 lines] > > > > 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 >it is impossible for the intake gasket to leak coolant into combustion >chamber on a 4.0 OHV. [quoted text clipped - 65 lines] >> > >> > 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. [quoted text clipped - 89 lines] > >> > > >> > 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. > it is impossible for the intake gasket to leak coolant into combustion > chamber on a 4.0 OHV. [quoted text clipped - 3 lines] > > Only a leaking headgasket or cracked head will do that Sorry, I believe you are wrong. In fact, based on my personal experience, I know you are wrong. The coolant gets into the combustion chamber somehow; it may be going in some other sneak path related to the manifold gasket. It will cost nothing to retorque the intake manifold bolts. Beats any of the other very expensive alternatives. The rear bolts are very hard to reach, requires a mirror to find them. Also, found out the spark plug order is Passenger Side --> 1 2 3 Front Driver--> 4 5 6 Side You might be right.......... I think im mixing the 4.0 and the 3.0 > > it is impossible for the intake gasket to leak coolant into combustion > > chamber on a 4.0 OHV. [quoted text clipped - 21 lines] > Driver--> 4 5 6 > Side I checked out my intakes and see it is going to be difficult as hell to get to the lower intake bolts without taking the upper off. So I ask, who out there has torqued the lower intake bolts without taking the upper intake off? How did you do it? Thanks, Sam in Raleigh. I did. Yes, it is somewhat difficult to do it, but with a long extension and some contortions, you can do it. Probably the hardest part is locating and seeing them. I actually climbed into the engine compartment so I could get my eyes vertical over the manifold to be able to see the bolts, but I was able to get to them by removing the throttle body plastic cover and maybe the throttle linkage (don't remember for sure). I remember that the rear bolts were the toughest to get to. They required a mirror to even seee them. Also, I might have had to move some sensor wiring or wiring bracket. >I checked out my intakes and see it is going to be difficult as hell > to get to the lower intake bolts without taking the upper off. [quoted text clipped - 5 lines] > > Sam in Raleigh. Ah hey thanks man. I just needed to hear from someone who has done it. I got the Ford Service and Repair Manual in case I need any tech specs plus a Haynes Manual and all the tools I need. Thanks for your input. The next time you will hear from me will be after I have tried to torque down the lower intake manifold bolts. If it does not make a difference then I will replace the upper and lower intake. Cross my finger :) -Sam in Raleigh. >I did. Yes, it is somewhat difficult to do it, but with a long extension >and some contortions, you can do it. Probably the hardest part is locating [quoted text clipped - 18 lines] >> >> Sam in Raleigh. Well I went ahead and tightened the lower intake manifold bolts today. The bolts were not obviously loose however I did manage to torque each one down via the torque pattern. The driver side bolt closest to the firewall had to be done by a small wrench as there was enough clearance between the firewall and the upper intake to get my hand back there. The front passenger side was the hardest and required a universal extension. I was so happy to get it done that I did not change the spark plug that was getting damp so I will do that this weekend. None of the bolts were "loose" however most all of them needed torquing down...if that makes sense. Guess I will post an update once it is determined whether the engine is still loosing cooland or not. Thanks, -Sam in Raleigh. |
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