1996 Ford Explorer 4.0 OHV Low Compression

[fast_dave]

Great information, but the O/P has an engine with a dead cylinder, for Pete's sake. No plug wires or computers are going to fix that!

@1998Exp

This is a long thread and throughout the OP has complained about previous cases of misfiring and recently has talked about loose plug boot.
On the OHV - you need to use the proper spark plug wires - I have no idea what he's using...
I do know when the wrong spark plug wires are used, misfiring on the OHV can occur at the coil as well as at the boot.
$22, 6 new plugs, and Dielectric Grease will eliminate that possibility and allow him to move down other avenues of thought - just sayin'
Sounds like he is overwhelmed due to his upcoming state inspection an

 

[TexomaExplorer]

Yes I am using the plug wires with retaining clips on them and lots of dielectric grease on both ends. I come from a marine world with mercruiser (chevy) engines, and its drilled into me about the grease to keep moisture out. The number 4 plug is such a pain to get snapped on with the egr in the way and the angle. The cables have been off the battery for a couple of days since I had to go out of town. Boats are so much easier to work on vs these new fangled motors with tons of sensors and hoses lol. This is the cracked head from before.

 

[TexomaExplorer]

Plugs back in, wires on, battery hooked up.. still runs like crap.. when it idles up, it smoothes out, but back to crap when low idle

 

[TexomaExplorer]

Surging idle, no power to go

 

[donalds]

Do another compression test to rule out rings looks like @fast_dave was looking in the right direction just sayen

 

[freak]

Seems like every few days an ohv explorer is checking in with this problem. The likely cause is a crack in the head. You have two options:
1) Repair the head, it is a permanent solution. There is a set of new heads on ebay for 400 bucks. Add $100 or so for gaskets and stuff.
2) K-seal, this is what I did on mine, seems to be holding very well. It will plug the crack. How long it lasts, I don't know. I have 5k miles so far. But my truck has some rust and it won't be around forever.

Does your coolant gauge move around? That would certainly be an indicator. You can also blow air in the cylinder and see if the coolant rises in the radiator.

I know this is an old thread but this caught my eye as I was reading... What is the correlation between the gauge moving around and a cracked head? I have an old tired 351 in an F250 and I see the gauge moving around. My coolant looks bad too.

 

[EB4X]

I know this is an old thread but this caught my eye as I was reading... What is the correlation between the gauge moving around and a cracked head? I have an old tired 351 in an F250 and I see the gauge moving around. My coolant looks bad too.

With a cracked head / bad head gasket, depending on area of crack, it is common for compression to now get into coolant path(s) through break and thus putting air into coolant system which in turn creates an inconsistent flow of coolant causing engine to warm up / cool back down in synch with now alternating air / coolant flow
P.S. These 4.0 ohv's aren't the head crackers some make them out to be....unless they are overheated bad.

 

[freak]

With a cracked head / bad head gasket, depending on area of crack, it is common for compression now get into coolant path(s) through break and thus putting air into coolant system which in turn creates an inconsistent flow of coolant thus causing engine to warm up / cool back down in synch with now alternating air / coolant flow
P.S. These 4.0 ohv's aren't the head crackers some make them out to be....unless they are overheated bad.

Good to know! Appreciate it!

 

[freak]

With a cracked head / bad head gasket, depending on area of crack, it is common for compression to now get into coolant path(s) through break and thus putting air into coolant system which in turn creates an inconsistent flow of coolant causing engine to warm up / cool back down in synch with now alternating air / coolant flow
P.S. These 4.0 ohv's aren't the head crackers some make them out to be....unless they are overheated bad.

If this is the case wouldn't it have to be continually pushing air out through the overflow tank?

 

[EB4X]

If this is the case wouldn't it have to be continually pushing air out through the overflow tank?

Yes, somebody having this problem will usually hear a whining noise...that is compression / air squeezing out of overflow tank, usually bleeding out crevice in cap.