Head gasket ordeal

[65Ford]

Hey all, hope someone can help. 94 B4000/Ranger 4.0. Blew a head gasket. Tore it down and replaced gaskets but reused old heads, didn't have any work done to them, stupid yes. Needed to get truck hopefully running to use for work. Any who, put back together and it still was streaming out tail pipe. Tore it back down, new gaskets, heads and bolts. Just started it and still steaming like before. I have factory repair manual and followed per instructions. Thing that was difficult was the final torque on head bolts in engine bay, the final 80 to 90 degree turn of the bolts. I had to use an extension on some of them and pretty sure I got the full required turn but it's the only thing that maybe I didn't do to complete spec. Any ideas what I cold be missing? Could block be cracked? TIA for help. Bill

 

[RonD]

If heads were over heated then one or both were cracked.

4.0l has a weak casting between valve seats, if overheated the metal expands and cracks between valves.
You can sometimes see it as a line but many times it is almost invisible.

If you mis-torque the head bolts the head gasket will still seal but will fail after about 6 to 9 months, so not right away.

Now I had my craftsman torque wrench for 25 years and it worked great until it didn't
It had lost about 20ft/lbs, so 60 was actually 40
I had to redo my heads 3 times, lasted about 9 months between failures, lol.
3rd time after I tested and found torque wrench problem and got new torque wrench.
All has been fine since

I did need to replace 1 head because it cracked, coolant leak and I "drove it home" without letting it cool down, so cracked the head, costly trip home.

So you should take your heads to machine shop to get cleaned, surfaced and pressure tested.
These engines should use composite head gaskets not MLS

You don't need to bolt lower intake down with the heads, it can be installed after heads are torqued down
That part was added because 4.0l lower intake bolts would loosen up over time and had to be retorqued, but it doesn't prevent loosening up, lol.
Use locktite on lower intake bolts

 

[65Ford]

Thanks RonD, heads I bought new. All gaskets, bolts etc. Are new on reinstall that's why I'm wondering what's going on. Torque wrench is relatively new with low miles on it and always suited with no tension on it.

 

[RonD]

Then thats a hard one

4.0l never had cracked block issues, not that it couldn't happen

And it almost always shows coolant/water in the oil pan, unlike head crack or head gasket issues.

If possible I would find out which cylinder has the leak.
Compression test doesn't always work because variance can be small

Glove test is free and easy, and can ID cylinder
With cooling system sealed up, doesn't have to have coolant in it
Cold engine
Remove rad cap and overflow hose
Seal overflow hose outlet with vacuum cap or ??
Place Latex Glove over rad cap opening and seal it with rubber band, you can also used a balloon or even condom in place of the glove

Cooling system is again sealed so any compression pressure from a leaking cylinder will cause movement in the Glove

Unplug the coil pack, you want a no start

Crank engine
Glove will bounce up and down if you have a cylinder leak into cooling system
Remove 1 spark plug at a time and crank engine
Glove will stop bouncing when spark is remove from leaking cylinder

If Glove doesn't bounce then you have a lower intake manifold leak #1 or #6 have the coolant cross flow, but #3 or #4 could also leak coolant into adjacent cylinders

Once you have ID the cylinder I guess you will be pulling off that 1 head again but this time have a specific area to inspect.

 

[adsm08]

How much coolant did you put down your pipes?

It can soak into the cat and steam for a while. I worked on a 6.0 once that had an EGR cooler fail and flood the cat with coolant. After I fixed it I had to drive it about 40 miles before the exhaust cleared up.

 

[65Ford]

Thanks guys for the replies. Ron D when I tore the heads off number 6 was steam cleaned and the head gasket was ruptured there. I can check for the intake leaking.

adsm08 initially when the gasket let go I nursed it home so I'm sure the cat got soaked but the truck sat all summer so it probably dried out??? I ran it the other night and it started to stream out tail pipe right away and i let it run for maybe 10 minutes. That would be great if it just needs to run enough to get hot and burned out any residualwater/coolant. Think I'm still using water. I filled rad to top and after running it looks down, check it closer tonight.

Thanks for the help and ideas.

 

[RonD]

Do the Glove test, and then go from that result

 

[65Ford]

asdm08, that looks like that was it, soaked cat/exhaust system. After running awhile it cleared up, no more steam. Thanks