These are the steps I took to get to the cylinder heads on my 1996 Aerostar, with a bad head gasket. I also had acess to service data, about torquing the heads, and intake manifold, but I did not find much information about actually getting to the heads.
I did this at home, in front of my garage, outside.
I would strongly suggest that if your Aerostar is still running, you pressure wash the engine compartment, being careful not to force water into electrical connectors, past seals, ETC.
I also had to go under the engine on the van, I put the front van up on two ramps. Make sure your Aerostar is secure and cannot fall with you under it.
I also had the rear two seats out of my van, and put a large sheet of cardboard in the back of the van to store the parts.
I started this project on 03/29/2010, and finished 04/16/2010.

Here are the steps:<title></title> <style type="text/css"> <!-- @page { size: 8.5in 11in; margin: 0.79in } P { margin-bottom: 0.08in } --> </style>

1. Remove right front seat
2. Remove anti-skid brake module from under dash, leave wires connected.
3. Remove interior engine cover
4. Remove battery
5. Drain coolant
6. Remove air intake tube off engine
   1. Remove air flow sensor electrical connector
   2. Remove air temp sensor electrical connector
   3. Disconnect vent tube to oil filler base
   4. Remove air filter cover, and air filter
   5. Remove lower air box
7. Remove serpentine belt.
8. Remove throttle body cover
   1. Tape screws to cover.
9. Remove upper radiator hose
10. Remove alternator, three bolts, set on inner fender where air box was.
    1. Put bolts back in alternator, secure them with tape.
    2. Do not need to disconnect any electrical connections.
11. Remove vent tube from oil filler base
12. Remove oil filler hose
13. Remove belt tensioner.
14. Remove bracket that holds alternator, tensioner, Idler pulley.
    1. Keep three bolts with bracket
15. Remove heater hose from manifold
16. Remove AC compressor
    1. Do not disconnect refrigerant lines
    2. Rear top bolt has stud for dipstick tube
    3. Remove ty wrap from hoses
    4. Set compressor in battery tray.
    5. Keep four bolts with compressor
17. Remove thermostat housing.
    1. Keep three bolts with housing, or in labeled bag
18. Remove hose from throttle body to evaporative cannister
    1. hose plugs into nipple on bottom of throttle body, and aft end of cannister
    2. square “u” end of hose is by throttle body
19. Disconnect two electrical plugs near center top of engine compartment
    1. Release connector half from body sheet metal.
20. Remove Idle Air control motor from upper manifold.
    1. Put in bag with bolts
    2. Label electrical connector.
21. Remove DPFE sensor.
    1. Two vacuum lines on bottom, go to pipe connecting exhaust manifold to EGR valve. You can remove this pipe, and keep it with DPFE sensor. A 1 1/16 wrench fits nuts on pipe
    2. Label electrical connector.
22. Remove EGR vacuum valve screws, vacuum tube from top.
    1. Label vacuum hose.
23. Remove power steering pump bracket, with pump
    1. done to get access to oil dipstick tube
    Remove EGR pipe to manifold.
24. Remove left side spark plug wires. Note routing
25. Remove right side spark plug wires. Note routing.
26. Remove primary electrical connector on coil pack.
27. Remove transmission dipstick tube.
    1. Held by nut on right valve cover stud. Stud located on rear of valve cover, toward center of engine.
    2. Tube goes through throttle cables
28. Remove coil pack, out through the rear interior opening.
    1. Four small Torx head screws, keep with coil pack, or label in bag.
29. Move throttle cables, and bracket to battery tray.
30. Remove two vacuum hoses from upper manifold.
    1. One is PCV hose.
    2. One goes to rubber mounted device on upper manifold
31. Unbolt “rubber mounted device” from upper manifold
32. Remove coil pack bracket.
    1. Has one single wire electrical terminal.
    2. Two bolts go into upper manifold.
    3. One bolt goes into right cylinder head, above exhaust port.
33. Remove six nuts for upper manifold.
    1. Two inner rear nuts also hold bracket for transmission dipstick tube.
34. Remove upper manifold.
    1. After it is pulled out, partially, disconnect brake booster hose.
35. Remove fuel rail
    1. Bleed fuel pressure off.
    2. Disconnect supply, return fuel lines
    3. Remove remove fuel rail/upper manifold bolts.
       1. Need female torx E-7 socket to remove.
    4. Leave injectors plugged into electrical
    5. Work fuel injectors out of fuel rail
    6. Work fuel rail off engine.
36. Work fuel injectors out of lower manifold
37. Disconnect wire harness from engine
    1. remove two temp senders connectors from lower intake manifold
    2. Remove oil pressure sender connector.
    3. Remove crank position sensor connector.
       1. CPS wire secured on right side of timing chain cover
    4. Disconnect black, with white stripe vacuum hose from black/white disk.
    5. Lay towel on floor inside van, carefully pull wire harness into passenger compartment.
38. Remove valve covers
    1. Inner back hole on valve cover has stud instead of bolt.
39. Remove rocker arms.
    1. Loosen three bolts together, one turn at a time.
40. Remove pushrods
    1. Keep in order.
41. Remove lower intake manifold bolts
42. Remove lower intake manifold.
43. Remove exhaust manifold bolts
44. Remove head bolts
45. Remove ground wire from right cylinder head
46. Remove cylinder heads.

 

This may be obvious, but before you re-install, make sure you have the heads checked. Usually a leaking head gasket is either caused by or causes head warpage.

 

I do have a precision straight edge, and I did check for flatness. Less than .003, in any direction, across the entire length of the head. There was an obvious spot in the metal ring around number six, right by a water jacket where I could see the gasket had failed. There was also some minor erosion where the water had been leaking on the cylinder head. I took the heads to a well recommended cylinder head shop here in Portland OR, for reconditioning.

 

Thanks for the write up..The only thing I would say is to leave the injectors and fuel rail on the intake and remove as an assembly. They can be a bear to get off on high mileage vans never mind trying to do it under the hood..


Dick

 

You are right, I could have done it that way, but, I did not. It looked easier to me to take the fuel rail off the lower intake, and I was having a little difficulty getting the clips off the electrical connectors to the fuel injectors.
Separating the parts also made it easier to clean everything.
Leaving it together, I would of not had to stop to go get a female torx E-7 socket.

There is more than one way to skin a cat, and one is not wrong, nor one right. They are just different.

The van has been running about a week and a half now, and I have put 222 miles on it, with no problems.

 

After I got the heads off the Aerostar engine, I gave then a quick rinse, and brush down in a solvent tank. I do have a valve spring compressor, and I took the valves out of the head. I did this mainly to check the valve guides. Without a spring, put each valve in it's guide, and try to wiggle it sideways in the head. If you feel a fair amount of wiggle, your guides will need attention.
A good cylinder head shop will tell you what you really need. find one you trust.
Keep everything in order and marked where it came from. Egg cartons work well for this.

 

The biggest part of prepping for the head reinstalling is cleaning the engine block mating surfaces. I removed the head locating dowels, and then carefully scraped ant old gasket off with a sharp wood chisel, being careful not to gouge the block surface. I then took a brass bristle brush, and cleaned the mating surface again, until it felt absolutely smooth to the touch, and looked good too. I cleaned the block with solvent, and put the locating dowels back in the block. I also chased each cylinder head bolt hole with a M12 x 1.75 tap. I chased each threaded hole on the cylinder head with the correct tap. Three above each exhaust port, and three on each end of the cylinder head, M 10 x 1.5, and the rocker arm bolt holes, M8 x 1.25, and the exhaust manifold bolt holes, also M8 x 1.25.
I did a final wipe down of the mating surface with acetone, and did a final wipe out of the cylinders with a clean rag.
The head gasket is marked "top" and "front". Put it on correctly. I then carefully put the cylinder head on the block, and I had a little difficulty getting the rear locating dowel to mate up. I put the left (drivers) side cylinder head on first, it is farther back than the right side. To get the back dowel to locate, I went into the passenger door of the van reached forward, and moved tha back of the head into place. While I was there, I put the ground wire for the engine back on the rear of the left cylinder head.

I had two different sources of service information, that mainly differed on the amount of torque for the steps of tightening the head bolts, and lower manifold.
I did use new head bolts. I put the head bolts in, and tightened then to the lower of the two different torque values I had, in the sequence recommended. I tightened them to 22 foot pounds, and after going through the eight bolts, I redid then again, some bolts were loose, and I took then up to 22 foot pounds again, until they all were at 22 foot pounds. The back bolts on the cylinder head, I had to torque through the passenger compartment.
The right cylinder head I installed in a similar manner.

 

After getting both cylinder heads on the engine, and lightly torqued, you are ready for the lower intake manifold installation. The service information from the two different sources I had available both said the heads and the lower intake get torqued together, at the same time in steps, and you install the heads, lightly torque them, install the manifold, lightly torque it, tighten up the heads a little, the manifold a little, tighten the heads again, tighten the manifold again, until you are done with all three parts. If you do not have service information get it. You do need it.
With the heads on the engine, and torqued to the first step in the process, I then rehearsed putting the manifold on. First, I put a pair of guide studs in the engine block, at the front manifold bolt hole, and the rear manifold bolt hole. I used a pair of old exhaust manifold bolts I was replacing anyway, the long ones, cut the head off of them, and then cut a slot for a screwdriver in the top of them. The exhaust manifold bolts are too short to stick out of the manifold bolt holes, I made sure I could push the screwdriver into the guide studs, and pull them out of the hole with the screwdriver.
I installed the guide studs, and then the manifold, without the gasket. I had to lower the rear of the manifold first, to clear the cam position sensor. I then put the six interior bolts in, removed the guide studs, and put the two end bolts in. This is all still the rehearsal, I was not trying to beat a flat rate.
I did this process again, this time with the lower intake manifold gasket, without using any sealer on the gasket, and took it apart again. Still rehearsing.
Now, the real job. You will need some O2 sensor safe silicone sealer. Put four small blobs of sealer at the corners where the cylinder head meets the engine block. Put a thin film of sealer over the water ports on each end of the cylinder head. Carefully put the gasket over the studs, and gently push it down into the sealer at the corners, and reapply four more small blobs of sealer in the corners, and on the water ports on the gasket.
Put the manifold on over the studs, and put the four middle bolts in, remove the studs, and put the end bolts in. torque the eight manifold bolts in the proper sequence to 3 foot pounds. After I was done, I checked the torque again, and retightned the bolts, again to 3 foot pounds. I did this a third time, and on the fourth time, the torque held on all eight bolts.
I then tightened the head bolts to about 40 or 45 foot pounds, rechecked them all, and retorqued the lower manifold back up to 3 foot pounds. Yes, the lower manifold bolts loosened when the head bolt torque was increased. I then torqued the heads up to 52 foot pounds, and tightned the lower manifold bolts to 6 foot pounds, and then rechecked the torque on the manifold bolts again.
The heads then got thier final 90 degrees rotation for torqueing, and the manifold bolts was then taken up to 11 foot pounds.
Check the manifold bolts again for torque.

 

Felpro increased the lower manifold bolts to I think 16-18 ft lbs. All the lower intakes I have done the bolts have been loose. FYI

 

When my brothers van needed some valve/head work due to low compression, I took the easy way out and bought some heads off eBay that already had the valve in them. I still haven't found what was wrong with the old ones, either a warped valve (#4 and #6) or a cracked head. Not sure which. The head gasket was in great condition. The new head made a huge difference and fixed the problem.

 

Thanks for the info about the bolt torque. My engine has had the head gasket replaced once before, at a dealer, and when I was taking it apart, It had Fel-Pro gaskets. when I was ordering other parts I needed, from one of this site sponsors, I also got a Ford valve grind gasket kit.
I will have to see if I can access any of the bolts with the engine together, and see if they are loose.

 

good write up DanielC

suggest using the upgrade improved 2 piece lower intake manifold gasket set instead of the OEM 1 piece. allows for the movement of the rock and roll high wobbly intake manifold plenum system on the 4L and still maintains seal.

FEL-PRO Part # MS98005T More Info {PermaDryPlus®; Set}
OHV engine; Valve cover gskts. & Upper set incl.; int. manifold gskts. incl.

also always check the ball socket on the rocker arms and the ends of the push rods. serious wear area on the OHV 4L and it's lack of adequate OHV oiling. insufficient oil flow through the roller lifters and push rods

 

At this point I wouldn't touch them..Should last 100k anyway.

 

might i ask where you took your heads to have them checked? I need to do this on my van this summer (replace pretty much all gaskets from top to bottom)...

 

Pretty much any automotive machine shop can do the heads. Some of the Checker O'Reillys have machine shops too. Make sure you buy new head bolts too.

A few other pointers. The head bolts are held in place with star head bolts, T55 I think. Try to get the shortest ones you can find, I found it tricky to get at the rearmost bolts of the drivers side due to clearance issues. Also, I did not bother with completely removing the exhaust manifolds. Yes, I unbolted them from the heads, once you disconnect all those, the manifolds will hang down a bit, getting out of the way.