Cracked block ? 84CJ7

[Jeeper Jay]

I thought perhaps that my new temp gauge was bad because it would move all the way to hot but the actual block temp was only 140F. I recently had my jeep at a local shop trying to get my weber adjusted. He said that the reason the temp is showing hot is due to a crack or obstruction in a water jacket. Apparently the block temp varys 100 degrees f from one spot to another. He mentioned that due to the way the block was cast this was sometimes a problem with this particular block (something about the block chipping away and obstructing the water flow) I've never read anything about this problem. Am I in the market for a new block. Or is it time for an upgrade (GM)
By the way I have eliminated all other usual overheating possibilities. I also did a test to see if any engine gases were entering the radiator, checked out OK.

 

[stumpbumper]

Is this the 4 cyl or the 6 cyl engine??
And what transmission!
I say don't waste your time with a jeep engine replacement! If its the 4 cyl? then its what is called a "Iron Duke" and has a Chev V8 bell housing bolt pattern.. very easy swap! you will need the flywheel and 4 cyl clutch parts!
If its the 6 Cyl then you can either put a V8 or AMC V6 back in or swap bell housings and use a Chev V8!

More info to help on swap!!!

 

[Jeeper Jay]

I have the I6 258.......Im still not convinced that I have a major problem with the block... when I measured the outside of the block with my infrared thermometer I came up with (after an hour of idling) 216 degrees right at the sending unit and lower on the block same 194. Up front on thermostat side 140 degrees. exhaust manifold side 250 on top just above manifold and 173 on block below. Question, What is the acceptable temp for the block, and, other than a cold hot reading what should the actual temp be .

 

[stumpbumper]

I have been around a lot of 258's.. The only problem I have had is cams.. they are known for flattening them..
I have actually had guys on trail run bust their radiators and run their engine dry, shutting it down from time to time and making it out of the mountains.. the next weekend they fixed their radiator and are running the same engine!
SO really what is the rig doing??
Does it use any fluids?? if so can you tell if water is going someplace!
Can you tell if the thermostat opens or not??

The only way the carb is effected buy a cracked block is by vaccuum! but that is not water blockage!
I would take it to a different guy and get a different opinion!

 

[Jeeper Jay]

different guy different opinion for sure ! I took out the sending unit, grounded it and boiled some water to about 186 degrees. The result was the (new temp gauge) registered -hot-. These guys were trying to talk me into a new engine. Plus offered me, get this, One thousand five hundred dollars for my jeep, Hell, The ramsey 8000 lb wench,hard top,heavy springs,body lift are worth more than that. I am trying to find an after market gauge for my temp. Then I may start looking into fuel injection and ignition upgrade,

 

[TeddESP]

Sounds like they were in the market for a jeep.