4.0 Intake question
 

As some of you know, I had a leaky intake gasket some time ago. Well now I am getting around to fixing it.

I have the upper intake off now, and when I look at the "built in gasket" I see that the rubber is minimally "higher" than the rest of the surface. How far out should it be and if it isn't out far enough to seal properly, what can I do for sealing the surfaces, short of replacing the manifold?

I'm not sure what you mean by the "built in gasket"? What year is this?

The leaks usually come from sealing problems on the lower intake manifold. The new gaskets I got from Fel-Pro had silicone rubber printed around the holes they're supposed to seal, and they are not raised very far; enough for you to feel with your fingers running over them. They should squish to near flat when properly torqued. It's unlikely that the intake manifold or that side of the heads can warp from overheating. However, it's quite possible to have corrosion eating away at the metal around the holes to cause the leaks. The recommended fix for severe cases is to weld up and machine flat. For moderate cases, I think the stiffer RTV (gray colored) can be used to seal it.

the upper intake plenum O ring gaskets are removable and replaceable
usually not included in lower intake manifold gasket set.
avail separately
FelPro pre 96
Plenum gasket MS94683

96 and 97
MS90733

Thanks for the replies and p/n's. It is the lower that is leaking, but I have removed the upper, and it does make sense that the rubber is replaceable (the oRings).

Once you get all the wiring and crap out of place, it isn't too bad to work on.

Your model year must be later than mine, to use the O rings between the upper and lower plenums, and the fuel rail.

But the Fel-Pro intake manifold set (MS98005T) that I got did include the O-rings and everything else needed to replace the intake manifold gaskets: valve cover, plenum gaskets, and a little tube of RTV for the manifold end seals.

Intake
 

I have a 1997, 4.0l, EAWD

I've wondered what those O-rings were in the gasket sets. (Mine use plain gaskets.)

I got the gasket sets from Amazon, whose net price was so much lower than other sources it was hard to go with anyone else, even for loyalty reasons.

Well, I finally got down to doing it...lots of little take off's before getting to the intake, but overall, it came off alright.

Some indications that this was done previously, and the leak appears to have originated at the point where the head meets the block (where you need to silicone).

There was alot of gummy crud around several injectors, and where the upper intake met the lower/fuel rail. Also alot of gummy crud around the fuel pressure regulator.

So, I bought a new gasket set, new injector o-rings, new fuel pressure regulator. I expect to be putting this together tomorrow sometime, hopefully it will work right!! I just don't like the idea of having to get in there to re-torque after running it....so much crap in the way.. :D

with the latest FelPro upgrade gasket set you have for the Aero, not necessary to retorque the lower intake manifold bolts after running

the sealing materials used work at normal air temps.

the critical part is completely clean gasket surfaces
i use crocus cloth to remove any old gasket and dirt from the metal , then clean with acetone or toulene, wear chemical gloves.
both safe with engines but keep away from many plastics and electrical wiring

clean air blow the rubber O ring grooves on plenum base for the rectangular O rings

soak the tips of your injectors overnight in 3/8" of acetone to clean the port, affects spray pattern....do NOT scrap the tip.

doing mine now. Aero 4Ls intake/ heads are not fun
the placement of the rear heat ac hoses over the top of the engine is stupid
Ranger/Explorer can be done in 3 hours start to finish.

use a light app. of thread non permanent Thread Locker on each bolt and nut...prevents the 4.0L shakes a part

The gaskests are only 1 part of the problem. The actual problem is the intake plenum itself. This has been a problem on the 4.0 Ranger since 1999. The issue is the seam where the plemum was glued from the factory to combine it as a sealed unit. The way to repair the issue is to either replace the plenum or get JB weld and locate the seam fault by spraying Carb cleaner in the seam area. You'll see it react when you spray. Silicone is a very temporary repair at best.

Uhm there are no '99 Aerostars. The 4.0L before and after '98 are somewhat different. Same block, but after '98 they switched to the SOHC. So I'm sure the later intake is different. So the previous post is not really irrelevant. The Fel-Pro gaskets seem to hold up just fine. For the record, Fel-Pro has two lines, the standard gaskets, but they also have a better line that uses a different formula. If you have a choice, get the better ones. Even so, Fel-Pro's standard line is better than OEM.

4.0 SOHC does not fit aero. we tried. it is too wide for aero dog house.

5.0 V8 fits. 2.4 Ford TDI fits. 5 and 6 cyl. mercedes E-class/sprinter fits. 4.0 SOHC and 3.8/4.2 Essex - unfortunatly dont.

When I read this, I got funny visions of Pablo and his friends trying shoehorn a SOHC 4 liter engine into the engine compartment of a butchered Aerostar. Pablo, do you have pictures of this effort you can show?

Someday, when the drive train in my Aerostar dies, I might want to try to install a 5.0 v8. I've seen a couple of examples already, so it must be possible without too much trouble.

4.0L Ford SOHC is the last engine in the world i would put or want in the Aero.
have to pull engine to remove right head. cam chain for right head is located on rear of engine and does not come off easily.
NOT a Ford better idea, just a cheap quicky fix to get the 4L into later emissions requirements. most of the power gains were above 3k rpm which does not help towing or with heavy loads. only about 20 lbs/ft of extra torque

I'd dump my Dodge/Cummins diesel in a second for a decent priced Mercedes diesel Sprinter but they're $50k with any options and Mercedes doesn't deal on price, full sticker or kissoff.

Actually, the 4.0L SOHC was a great effort. It launched the 4.0L from a pushrod into the world of overhead cams. While the SOHC may not have been the greatest result, it does produce 40 extra horsepower, and at no point in the torque curve does it drop below the output of the OHV 4.0L. The SOHC design had nothing to do with smog requirements, the old 4.0L can easily meet even the current standards.