SO, the previous owner of this '88 XJ did a whole lot of hackish junk to it and I have been trying to get it all straightened out and non-hackish.

One of the things they did was to bypass the heater core by just running the output hose right back into the return. The heater core hoses are just sitting there hanging freely.

I could easily just connect the hoses back and route coolant through the heater core, and actually have a heater this winter, but I fear that they may have bypassed the core for a reason. Perhaps the core was/is leaking?

Is there some easy way to check if the core is ruptured without risking coolant leaking into the cab?

There are more cooling system issues too, such as the overflow tank is not even connected to the system. It is like the dude just did the most hackish job possible and all the coolant/water in the system is contained within just the radiator and the block and the hoses... Royal pain in the astlebar...

 

Sounds like you need to begin with a new heater core, and go from there.
A factory service manual, (Ebay etc) would help a lot to get your Jeep back to where it should be.

Bill

 

Hook a hose up to one side and cap the other off. Start flushing water in there and build up some pressure and see if it leaks. Best advice I can give you without physically pulling it out

 

Coulda been leaking or clogged.

Look under the passenger side carpet......

Do you want me to look at the underhood hacking on your Jeep and/or compare to under my hood?

 

I have been straightening it up, but there is still more to do...

 

Looks like it has the '91 up "open system" radiator conversion and the open system MUST be plumbed (rubber hose) from the nipple below the rad cap to a recovery bottle that fills/empties at the bottom and the bottle must be open to the atmosphere.

Another thing to be cautious of is, I don't think the later model "open system" radiators have a coolant temp sensor (for the efan) in the side of the rad like the "closed system" rads have......so how is the efan being activated by the coolant temp sensor when needed?

Some hack jobs r simply incredible.......but hey, it's amazing that the fan shroud is still there.

 

The radiator has a neck for a radiator cap so I think it was swapped from some other Jeep or maybe ordered that way. The little hose from the rad cap to the bottle is all hacked up too, and I will replace that soon.

By 'hack job' I mean that whoever did this stuff to it did half-**** ghetto-style work to it. It would have only been a few dollars more to do it right, but they skimped on everything.

I might just leave the heater core bypassed because I am back in Phoenix now and it doesn't get cold enough to use the heater....but I do need to make sure the system works properly cus come summertime it gets really friggin hot and I don't want to be blowing steam...

 

Some replacement radiators for open systems have the bung for the fan switch.

 

That's good info to know. Knowing that tidbit should be helpful to someone doing the conversion.

 

Keep close tabs on the coolant level in the rad 'til that situation is corrected. Check coolant level in the rad, motor COLD, very frequently......as in each time it sits/cools and before starting again. When hot, coolant exits that nipple and air is sucked into the rad when the motor cools. Multiple heat/cool cycles means more and more air in the system if coolant is not replaced.