Where does the head crack?

[94 green explore]

Where does the head USUALLY crack?

One of the head repair products in a can (CRC) says to remove the spark plug and unplug the injector of the cracked cylinder. I do not know which cylinder I should be looking for or how to tell which cylinder is the culprit.

Im sure it is the same one on either head.

Any input would greatly appreciated.

I have searched but did not find this type of information.

 

[Stick4503]

It's not that easy. You can't just look for a crack. You need to do several test to find the crack in the head gasket.

Cylinder compression test.
Cylinder leak down test.
Inspect each plug for signs of water or oil related damage.
Among other things.

 

[turboranger91]

Are you asking where the head normally cracks, or where the head gasket usually let's go?

 

[94 green explore]

turboranger---Where the head normally cracks.

Directions say to remove spark plug from the cylinder that has the crack. I think that is so the pressure from the affected cylinder does not blow out what ever the material is that is added to the cooling system to hopefully fix the problem. For the short term.

 

[94 green explore]

Stick4503 -- The ex has not run in over a year. The previous owner said it was heads or head gasket. The oil is not mixed (at least not on the dip stick). Radiator was already removed. Oil level is slightly above full. slightly.

I have not pulled the plugs yet but I would guess they are dry after this long.

I just figured that these heads would always crack in the same location or in between the same cylinders.

 

[Maniak]

Here are some pictures of some of the cracks on the last set of heads before I got rebuilt ones.

4.0-head-cracks-93tms 003 by maniak_az, on Flickr

4.0-head-cracks-93tms 011 by maniak_az, on Flickr

4.0-head-cracks-93tms 007 by maniak_az, on Flickr

4.0-head-cracks-93tms 009 by maniak_az, on Flickr

4.0-head-cracks-93tms 001 by maniak_az, on Flickr

The head that I got last time that was bad from the rebuilder was cracked on the top, on one of the humps...

~Mark

 

[94 green explore]

Maniak -- Nice photos. I have never seen that side of a head personally, but those helped. Thank you. But is there a particular cylinder that this happens to? #1 , between 1&2, #2 , between 2 &3, #3 . Same for the other side with 4,5,6?? At this point just curious which cylinder or water port is the bad one. OR is it so random that it can be any one of the 6?

 

[94 green explore]

bump

 

[Maniak]

From what I remember from my research when we cracked the first set of heads, it's the passenger side, towards the rear that seems to crack BUT from what I've personally seen, it doesn't really have a pattern..

They crack between the valves, between the water jackets and IIRC the 93tm heads have a thicker casting on the humps so that must have been what ford thought what an issue.

~Mark