For some background, here is a post of mine a little while back:

Well, as I've been telling Ken00 and Bob Ayers, I checked my coolant level this past weekend and it was low again, and I had just replenished it about a week ago.

So I figured it was time to get off my fanny and replace the Lower Intake Gasket, no more hoping that it hangs in there a little longer. My Ranger’s exactly at 125K so what am I waiting for? The original gasket has served it’s purpose long enough, I can’t really complain. I'm betting that I only just crushed down the deteriorating rubber areas on the original gasket when I previously re-torqued the lower intake bolts.

So, low and behold, I am currently in the process of the repair. I will be picking up the Lower and Upper Intake Gaskets from Ford and the Valve Cover Gaskets (non-cork Fel-Pro’s) from Advance Auto later on today. I'm plugging away on the project slowly, since I'm fortunate enough to have other wheels to drive around in, and this being my first time through this on the 4.0L, I don't want to screw anything up, either.

I've read a lot of posts from guys who tear apart the top ends of their 4.0Ls in an afternoon and I'm wondering how the heck they can do it. Must be darn good wrenchers.

For me, getting to the lower intake was kind of a PITA. It's not so much the wrenching, but the tight fit inside the engine bay, and with things such as the wiring harness and A/C lines snug against the engine, normally simple tasks like unplugging fuel injector harness connectors, for example, are tedious tasks in their own right. Pulling the valve covers was a very tight squeeze. And as I am sure you are all aware, there are quite a few vacuum lines and plugs that have to be kept in mind just getting to these things (although I have to say that the instructions from the Ford Manual are pretty good on that).

Lower Intake (Bottom View)


Lower Intake Gasket


Lower Intake Gasket (Rubber End Close-up)

 

BTW, this is why I elected to go with the OEM Intake Gaskets. The Fel-Pros are good, but the Ford Gaskets are better, according to most 4.0L gurus. Supposedly the Fel-Pro Intake Gasket uses cork on the ends, as opposed the rubber that Ford uses. Makes sense to me, anyway, and I figure I can't go wrong with OEM.



However, Fel-Peo makes an excellent Valve Cover Gasket for 4.0L, not the cork ones, but the "Performance Dry Plus" gaskets, which I am going with. They are $14 each (Part # VS50368T) at Advance Auto.

 

Nice pics Rockledge. I agree about the gaskets, why cut corners on this job. keep us updated on your progress.

 

Just a note before I store away the sales slip:

Upper Intake Gasket: Ford Part # F57Z-9E436-AA which covers '95-'00. This is actually a set consisting of 3 "Double O-Ring" type rubber gaskets that get tucked into the upper intake, resulting in a thin rubber gasket surrounding each port. Current list price is $14.22 for the set of three.

Lower Intake Gasket: Ford Part # F7TZ-9E439-AA which covers all years. Currently lists for $ 31.51.

Also, I elected not to detach the Fuel Supply Manifold from the Lower Intake Manifold. I pulled the whole assembly together, fuel injectors and all. I figured that I was not getting any lean codes, which is what a bad Fuel Supply Manifold Gasket would cause. However, if you have a 1997 4.0L, I would probably not advise this. For some reason, for that year only, the gasket located between the Fuel Supply Manifold and Lower Intake Manifold can lose its compressive loading and get drawn into the intake manifold runners, resulting in a vacuum leak/lean condition and associated codes. A new, redesigned gasket has been used ever since (TSB 98-6-8). So if you are doing this kind of repair, replacement of the Fuel Supply Manifold would be adviseable on the 1997 models.

 

Excellent posting; please keep us updated. I'd say this thread has potential to be added to the technical information sticky; good job Rockledge!

Another thought for others doing this work or any other work where vaccum/electrical/mechanical things are being disturbed.......take pictures of things before dissassembly. I've done it myself and I've found it very helpful during reassembly. Don't hold back on the quantity of pictures.

 

Good tip on the pictures, Bill. A digital camera is truly a useful tool when it comes to this type of project.

Well, this afternoon I made some pretty good progress. I was able to get the lower intake, valve covers, and upper intake installed before it was time to quit. Yesterday afternoon, after picking up the new gaskets, I had taken some time to thoroughly clean all the gasket surfaces and put a wire wheel to all the nuts and bolts. I also had previously cleaned up both intakes the best I could, using solvent, a rag, and a small, fine-wire brass brush on the metal parts. Cleaned up pretty nice. So I was pretty much ready to start installing things today right off the bat.

I used long zip ties to help keep the wiring harness(es) out of my way when dropping in the new lower intake gasket and then the intake itself. Also helped keep them out of the way when installing the valve covers, which require a decent amount of negotiation to get back on. The key (as usual) is not to force anything!

Before doing anything though, I pulled out my little shop vac and did my best to remove all possible traces of dirt that I might have left. I have some accessories which can get into some pretty small nooks and crannies.

The actual installation of the lower intake and gasket is very straightforward. You just have to make sure you put a little bit of RTV on the ends where the instructions tell you to (it's obvious when you're looking at it, as well).

By far, the biggest obstacle to my progress today was that freakin' EGR tube which connects to the upper intake and is bolted to the EGR valve. It is curved at the end, and protrudes several inches into the intake. That stupid tube had already gotten in the way when I was pulling the upper intake, so I thought it might be a PITA come time to reinstall it, and I was right on about that. I mention this because the Ford Manual doesn't really say much about it, and yet it is something that can cause a great deal of aggravation.

So I guess you can say now that I’m coming down the homestretch

Here's that problematic EGR Tube that connects to the Upper Intake:


My 4.0L Upper Intake Assembly. Notice that you don't need to remove the Throttle Body, IAC, DPFE sensor, or Coil pack:


Upper Intake Gaskets:


Shot of the new Fel-Pro Valve Cover Gaskets being installed:

 

Glad to hear things are going good Rockledge, nice tip on leaving everything on the intake, keep us posted.

 

I'm finished!!!

It took me a couple more hours today, but I'm all done. I re-connected all the cables, wires and hoses and then double checked them. Not difficult, just takes a little time, especially because it's my first time buttoning it all back up. I topped off the cooling system and re-connected the ground cable to the battery.

Before actually trying to start the motor, I left the harness connector off the the coil pack and cranked it several times so as to prime the oil and fuel systems. Then I hooked back up the connector, cranked it again and...

BINGO! Truck started right up and started purring like nothing had ever happened. This was a very good first sign!

So I put the hood back on and anxiously hopped in the driver's seat. I drove around for about 25 minutes, both highway and city, and everything feels great. The motor seems even peppier now, probably because of the ports being nice and clean, and also the new spark plugs (Autolite DPs) I elected to put in. Smooth idle, no CEL, and I even plugged in my scanner just to be sure that there were no trouble codes. After the ride I checked for coolant leaks but found none, and didn't expect to. I have faith that I did the job properly, by the book.

I realize that the true test doesn't come for a while, not until I send another oil sample to Blackstone Labs and they come back telling me that there is no more coolant getting into my oil. But again, I feel pretty confident that I have identified the problem and resolved it (with lots and lots of help from my FTE pals, of course!).

Soon I hope to add another post to this thread setting forth the steps required to do this repair.

 

OK, I finished putting together the tutorial on how to replace the lower intake, upper intake, and valve cover gaskets on the the 4.0L OHV engine. I utilized a few different sources and threw in some of my own info and experience with doing the job.

Because the addresses of the pics I used are likely to change at some point, I decided to post the tutorial in PDF format, so that the links won't go dead over time.

So, here it is, please look it over, let me know what you think:

 

Hi all,
Have a 91 Ranger 4.0 (4X4) that is loosing Coolant by not leaking. Took it to the Radiator shop and Pressure Tested Okay with no Leaks. I also checked the Spark Plugs and they have a Normal Brownish Color and the Engine runs Great. It used about 1 Gallon of coolant on a 900 mile trip (had to add some every 150 miles) but engine doesn't sputter and has plenty of power.The procedure : http://rockledge.home.comcast.net/Ra...eplacement.pdf
listed in this thread (BTW is Great Rockledge !) and Seems to cover 92-98 4.0 Engines.

I don't want to tear into the replacing Intake Manifold Gasket unless sure. Is it a Good Bet that is what is wrong with 91 4.0 also or is there a Quick Way to check for Coolant in Oil or Exhaust ? (Presume it takes Awhile for oil sample results to be returned from Blackstone Labs)

Any Help would be appreciated as I have a 900 mile return trip next week

 

Hi there and Welcome.

I was in a similar situation a few months ago. My 98 4.0 was losing coolant, and would stumble a little after about 30 seconds of running. It passed a pressure test. I didn't have the oil checked, just went ahead and changed out the lower intake manifold. Well it ran better, no more stumbling at start up, but still the coolant went away. I'm thinking cracked head.

Then I noticed coolant leaking out of the heater control valve. This would only happen if the heater was on the off position, or in AC max, but if I applied pressure to the rod that comes out of the valve, coolant would stream out when the truck wasn't even running. I replace it a couple of weeks ago, and have only driven about 200 miles since, but the coolant level is still up. So I'm hoping that was the problem.

If it was the problem then I may have replace the lower intake gasket without needing to, but the stumble at start up did go away, and the cost was less the $100.00. Plus it was a good learning experience.

The point of my post, you may want to check for other leaks before tearing into the motor.

 

Hello, welcome to FTE! Thanks for the positive feedback.

It's pretty hard to tell when it's cold outside, but white, lingering smoke out the tailpipe is a sign of coolant in exhaust, especially at startup. Do you ever catch a whiff of the sweet stench of coolant? These are some of more common but less scientific ways of sniffing out the problem (pun intended).

Something to note is that the earlier 4.0L heads are more prone to cracking than the later heads,

http://www.babcox.com/editorial/ar/ar40123.htm

which in your case probably only makes it less of a certainty that the lower intake gasket job will cure the coolant loss problem. Bottom line is that tracking down small internal coolant leaks is never easy.

I recommend that you have the oil analysis done. You really need some sort of certainty on where the coolant is going. It's the best place to start, IMO.

 

Thank You Rockledge and mfriesen for the Advise !

I will Take your Advise and have the Oil Checked for Coolant Residue and Check the Heater Control Valve. I really would like some sort of certainty on where the coolant is going.

If that does not correct the problem and it is a Cracked Head, can you get Cylinder Heads now that are not prone to Cracking ?

Also thinking about a new Long Block since the Truck has almost 200,000 Miles.

Thanks Again for the Great Information !

 

Hi Guys,
It has been awhile but I had the Engine oil Checked for Coolant and it came back positive for Coolant in the Oil. I guess that still does not tell me if the Problem is a Cracked head or Intake Gasket Leak ?

I am thinking about using a Cooling System Stop-Leak like "Barrs for Large Leaks" (with the Pellets) that says it works for Radiators and Engine Blocks.
I was concerned that the stop Leak would make it into the oil like the Coolant has been and plug-up the Oiling system Lifters or Oil Filter with the Stop Leak.

What do you think ?
FordsForFishing

 

dont use the stop leak stuff, it will cause more harm than good.