'91 Intake manifold leak. common?

[Tony H]

After a drive the other day I got a leak, It's in the front of the engine, I thought it was the water pump. Nope. As I followed the leak up it looks like it's the Intake Manifold. Just to the Left of the Thermostat housing.
I mentioned it here at work and two other guys with that engine had this issue. Is this a common problem for the 4.0 V6?

Not too famoliar with this engine. Does the gas lines run into the Plenum? I guess the Plenum comes off then I can get to the Intake Manifold Bolts.?
Anything weird that I should know?? Of done many Carburated manifold before..this is my first Fuel Injected one. So if there are any secrets, I'm all ears.

 

[Tony H]

One More Question

One more question: Can I take off the upper manifold (plenum) then take off the Lower Manifold and leave the Injector rail attached to the lower Manifold.
Just trying to get to the lower Gasket for replacement with the least amount of pain.

 

[estan]

I had the same water leak on my 93 EX. but only mine was in the back pass. side of the intake gasket. The gasket got a crack right at the corner and was letting water seep out at a fast drip when it go hot and built up pressure. Yes you can take the whole upper and lower intake off together only needing to buy the lower intake gasket! You will have to take the valve cover loose or off ...as they bolt ontop of the bottom intake maifold, but I did not replace the valve cover gastkets and they were fine.

Hope this helps!

 

[jimbo74]

its a very common problem on the explorer

 

[Tony H]

Thanks guys. I think I lucked out.
I snugged the nut directly behind the Heaterhose on the manifold, no more leak. I didn't Torgue it to 18 ft lbs but It was definitely looser then it should have been. Quick fix. Well not really. The Nut was within eye shot but I had to take off the Belt tensioner and the Thermostat housing and take off an Injector wire just to get a Socket on the Nut. Better then pulling it all apart I guess.

ESTAN, So it is possible to get to all the bolts with the upper Manifold on? Interesting

 

[Rhett]

That kind of leak was even more common on the 2.8/2.9L (Bronco II, some rangers I think) engine. The 4.0 OHV, developed from the 2.8/2.9 Cologne, had the same problem, maybe not quite as prevalent..

On my 94 I had to remove the entire upper intake manifold to access all the bolts. On older trucks (pre 93) that don't have EGR, etc. it's sometimes possible to bolt them up with the upper manifold on. With enough swivel sockets I probably could have done it. But I wanted to do it right.