Changing Ford Explorer 4.0 V-6
Valve Cover Gaskets


Contributed by drbob

Drivers side: remove the air duct from the MAS to the throttle, remove the belt, remove the AC compressor and unbolt the hose across the intake manifold, Remove the wiring from the compressor and the valve cover, and lift the same harness off the stud at the top rear of the cover. Plug wires come off of four holders. The vacuum hose from the carbon canister comes off the connection at the throttle, and the hose is pulled out of the way. PVC valve and hose come off, plus the power brake vacuum hose and two other hoses that run around the right side of the intake manifold. make sure there is no debris ready to fall in when you get the cover lifted. Remove all the bolts holding the cover down, and carefully remove the cover. This takes a little work because of the fuel hoses at the front, but it will come out.

Passenger's side: Disconnect the battery and remove it. Remove alternator. Drain coolant and remove top radiator hose and heater hoses. Make a map of left-side spark plug leads, and remove them from the coil module. Unplug the low-voltage connection from the coil. Three bolts to remove the coil module and the local plug wires. Lift the wiring harness from the attachment point at the front, and from the stud at the rear. Undo the bolts and stud, and remove the cover through all the remaining maze of wires. This is the tougher side because of the AC evaporator and the suction hose across the top of the manifold. You will invent new words to describe your enthusiasm for this job.

I had a set of cork/composite gaskets purchased a few years ago for this job. Since then, there are metal/neoprene gaskets that are much better. $48 from Pep Boys in hard composite plus neoprene (special order), $65 from NAPA in metal plus neoprene (in stock), or cork/composite from Pep Boys for $34. I opted for the metal/neoprene since they are the best available. Get a tube of hi-temp RTV gasket maker, plus some adhesive to hold the gasket to the cover during installation. You'll be doing a lot of wrestling to get the covers back in, so use a good adhesive and follow the directions on the label. Don't over torque the bolts! RTV sealer gets used on the joint where the manifold joins the head to seal that little bump, and also on the bolts at the top under the heads for a seal there.

Biggest damage and leakage was where the gasket was burned directly above the exhaust ports at the bolts. Since the oil looks like it is coming up through/around the bolt, you might try as I did and put the recommended RTV gasket maker around the holt hole of these bolts, and then carefully reinstall those bolts. Two bolts on each cover are the critical ones, right over the exhaust ports. I delayed this job for a few years by sealing the bolts like this, but obviously I was in there eventually, doing it right.

 

Handy tools: I have a very short flex-head ratchet (6" handle) that is perfect for those rear bolts on both sides. 4" extension and a deep 10mm socket make that work. Rest of the bolts came out with a long extension. A good magnet and a spring-type pick up tool make recovering the bolts possible.

Clean everything before you start. I can eat lunch off my engine on most days, but I still got my hands dirty. I wear gloves so no big deal, but...

For those interested, 128k of synthetic oil means there is absolutely no difference in appearance between the valve gear and covers on mine vs a new engine. The inside of the covers doesn't even have a yellow/brown film on them, and the springs/retainers, castings are spotless except for a fine oil film. The rest of the engine looks the same inside.... I hope!

Anybody with an early (91-92) should carefully check plugs for oil in the middle cylinders. If there is any evidence at all, replace the intake gaskets while work is already done for the valve cover gaskets.

The valve cover gasket kit includes the gaskets for the upper intake manifold. These are different from the ones you might want to change (lower...), and are not necessary for the Explorer valve cover gasket swap. The Aerostar 4.0 has a different upper manifold configuration, requires removal to get the valve covers off. Thought you might get curious about that.

Almost forgot: "Assembly is the reverse of disassembly!"


 

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Added August 26, 1998

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