2000 ranger 4.0 issues

[Grego50]

I've owned this truck since brand new and it had never been overheated. Don't tow with but haul occasional firewood.
It's been going through some coolant, but been writing it off to a slow front cover leak. Than started going through cylinder #4 spark plugs every couple thousand miles. Now have o2 sensor lean code bank #2 . Oil lab test show small amount of coolant in oil test. Also stumbling idle but still drives fine. 175,000 miles.
Pulled into the garage today and pulled all the plugs for a compression test.
#1 180lbs, #2 165, #3 177, #4 163, #5 0, #6 182. Not good.
Going to figure up how to do a leak down test tomorrow and find out where that compression is going in #5 .
Replaced upper and lower intake gaskets about 5 years ago.
4.0 engine.
Definite head gasket at least?

 

[Grego50]

Today I removed the upper manifold and the left valve cover. turned the crank until I had #5 cylinder at top dead center. The springs, pushrods, and everything appears normal looking. screwed in a test hose and applied pressure to #5 cylinder.
All air pressure is shooting out the top of the lower manifold port for that cylinder.
sounds like a burned up, blown up, intake valve? Anything else I should look at before tearing this thing down to inspect further? I have the factory service manual for this truck on cd. first time tearing this deep into a Ford V6 motor.
Thanks, Greg.

 

[Grego50]

I have cracks in both heads.
Who's cylinder heads are recommended?

 

[RangerX]

I found this thread: http://www.explorerforum.com/forums/showthread.php?t=419523
I realize it's talking about 1st gen Explorer 4.0s, but maybe they have heads for your year too...

 

[Grego50]

Ordered the Promaxx heads this morning.
Talking to the sales person on the phone he claimed new ownership for the past 3 years.
Told me you would have to try very hard to crack these heads, they are reinforced in all the weak OE areas.

 

[RangerX]

Nice, let us know your opinion of them when you get them.

 

[Grego50]

Hello Moderator, RangerX,
Yes, and I will share my results with this forum.
I have read quite a few posts on these type of subjects, and the end result is never posted.
I can clearly see from the stamp on my OE head gasket, that the factory used a Victor gasket on this built.
Called a dealer in Seattle WA today, and they say there is nothing available in the area, and they could have gaskets in buy Tuesday for 48.68 apiece.
Would like some opinions of what people have been useing with good results? Also, what are the latest and greatest that guys are useing for the upper and lower gasket sets.
My heads were cracked at #4 and #3 cylinders, between the intake and exhaust valves bottom of the heads.
Looking for what others have had with good results.

 

[Grego50]

Not a very good first impression.