XJ-kee

So, logic tells me that my heater hoses are NOT backwards, because it seems weird things would happen. Installed a new head this weekend, and replaced most of my hoses while I had everything off. Took a lot of pictures so I know that these are connected the way that they were before I took the head off.

Saw this in the FSM while looking at something else. The FSM shows the hose from the thermostat going into the bottom connector of the heater core, and the water pump one going into the top part of the heater core.

Mine is definitely different than that, pic attached - red to red, white to white. Googled some other engine bays for a 2000 XJ and others seem to have the same hookup as I do. Anyone know if the FSM is just wrong? On a somewhat related note, engine started getting a little hot (220*) on the way home so I popped the hood. I have coolant now leaking out of the top of the radiator cap which I did not have any leak there before. Possible that the cap is busted somehow, or would (if) backwards hoses have that effect on the rad cap? Since I had the cracked head beforehand, I wondered if my radiator cap was just bad to begin with but the pressure was releasing into the motor and now that that crack is gone, it's finally releasing releasing out of the cap?

Thanks

Chonson

My hoses are stock never been changed and they look exactly like your picture and not the FSM. Very strange.. I have a 2001

Also I recently flushed my radiator and when trying to flush the upper hose that leads into the thermostat housing the water refused to pass and all backed up, is this a sign of blockage? Or something different.. Im sorry for slightly hijacking your thread 😁

IJM

Were you squirting water into the upper rad hose in the direction of the radiator or in the direction of the engine? If the latter, the t-stat would be closed, and water wouldn't go anywhere except for a small amount. If you want to flush the block, you need to squirt the water into the small heater hose outlet on the same t-stat cover. That one bypasses the t-stat. It's circled in red in the picture above.

If you were having problems flushing the radiator through the upper hose (assuming the lower hose was disconnected, of course), you have a clogged radiator.

EDIT: OP, my hoses are just like yours. I don't think it would really matter either way, as I believe both the feed and return connections on the heater core are on the top. Flow direction probably wouldn't be a big deal either way.

Chonson

Ah, that was my mistake and you are absolutely correct only a very small amount was able to pass the t-stat. I was using the wrong hose. Thank you!

DFlintstone

IIRC DJB posted that they are different sizes. 5/8 for one and 3/4 for the other. Don't trust me on that!

chief turbo

does anyone have a part number for that hose that are connecting to the upper part of the heater core (the ones circled in red?)

mine is cracked and leaking and the parts store people are quite lost when looking stuff up over here

thanks!

DFlintstone

You can just use heater hose! (the "lost people" have roles of it). Sometimes you need manufactured bends, here you really don't.

(btw the # is in the photo, I think the fuzzy one is an 8) Oh..maybe there are more..

ehall

There's nothing directional about it. One of the tubes is larger than the other, match hoses to tubes and close it up

cliffy

I bought mine at autozone, it was a dayco #88429

cliffy

I just swapped mine and removed the heater control valve, it was a 5/8" on the bottom and a 3/4" on the top. For the OP, my hoses are the same way as your picture not the manual drawing.

madmanmarty

I would delete the HCV, flush the heater core in both directions,remove the thermostat housing,flush the block,install new thermostat,gasket,all hoses,coolant with distilled h2o,radiator cap.
I would also pay particular attention to the radiator. I'd flush and inspect throughly.
Fear is always why did the jeep overheat in the first place.
With a new head I would do all I could to insure my jeep was 100%.

cliffy

HCV was deleted with the '97 wasn't it ?

ehall

yes but the air ducting in the dashboard was also changed. On the old style, the air always blows over the heater core on cold and through it on hot, so if you delete the valve then you have to keep the temp at max cold or else it picks up a lot of heat and even then its not quite as efficient.

thatXJguy

Thicker hose goes on top, thinner hose goes on the bottom. Same on mine.

cliffy

Thanks for the explanation, I deleted mine awhile ago when I replaced all of my hoses and yes I can feel the warmth from the dash a little.