Heater Core Water lines

Heater Core Water lines

Duhwhat

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Location
Madison, Ms
Vehicle(s)
1986 CJ7 2.5L 4 cylinder
T-4, Dana 300, AMC 20 rear end
Does anybody know if it makes a difference which of the two water lines go to which heater core connection.

I am having a tough time diagnosing my cold heater air root cause and if it makes a difference I will swap the hoses/connection to core to see if it makes a difference.

So far I have flushed the core once with a water hose.

I put a new thermostat in last week.

The trap door that is operated by the cable labeled heat --->max seems to be operating correctly and makes movement noises. I can't see it, so not real sure whats actually taking place.

I have felt the hoses after running it 30 mins or so at highway speeds and there may be a slight difference in temp from one core hose to the other but not significant.

Funny thing, even the hose from the block to the radiator is not hot to the touch, just a little above warm.

Fan works fairly well, don't know if I want to mess up my firewall paint to install a bronco fan motor.

I live in the sunny south and my jeep is only driven for pleasure so I can leave it be if it is too cold.

That said, I would like to get it working anyway.

I really think I need to flush the core some more and bought some Preston flush this morning.

So back to the original question, does it make a difference which hose goes to which heater core connection?
 
what temp thermostat did you put in?
 
Pull out the "air" knob. it should be the one on the bottom. Let me know if it makes a difference.:cool:
 
what temp thermostat did you put in?

I honestly don't know. I just got the one the guy gave me at autozone for the 2.5L. Didn't anticipate a problem with different temps.
 
Pull out the "air" knob. it should be the one on the bottom. Let me know if it makes a difference.:cool:

The bottom is defrost. Nothing but cool air with that one. Same with Knob two from the top that says Heat ---- Vent. Nothing but cold air coming through.

(1) - Fan
(2) - Heat - vent
(3) - temp --- max
(4) - defrost
 
do you have 2 and 3 pulled out?:cool:


The bottom is defrost. Nothing but cool air with that one. Same with Knob two from the top that says Heat ---- Vent. Nothing but cold air coming through.

(1) - Fan
(2) - Heat - vent
(3) - temp --- max
(4) - defrost
 
Do you only have the heat/vent pulled half way out? if it's all the way out it's on vent and not heat.
 
@Old Dog and I/O

Yes, I think I am operating the knobs correctly.

I finally found a thread that talked about the hoses and the participants felt it doesn't matter which hose goes to which connection.

However, one said it would probably be better to connect the hose from the water pump to the Lower heater core tube.

Personally I just have to think the core is stopped up and the water is mostly bypassing the core if that is possible.

One thing I noticed the first time I took the hoses off is how nice and green the water was in each tube. Then when I flushed it I got some brown water out. This leads me to believe the water either wasn't passing through the core or it was only passing in the part that was unblocked.

I mean heck, this isn't that complicated. May be a new core in my future.

I am going on a super flush mission to see how that works out.
 
I guess I never said, but I don't believe it make a difference how they are hooked up.
Try disconnecting both hoses and sticking a garden hose to one side and see if it looks like it's flowing through ok.
 
Wont hurt to also check your thermostat housing gasket. I dont know about the 2.5 but on a AMC 258 i6 / 4.2l there is a separate slot where the heater return line comes in, I've seen them plugged or partially restricted, especially if the installer used alot of goop putting it back together. Just a thought.

Al
 
I like to hook mine to the bottom outlet. I would do the garden hose both ways and see how it flows better.
As for the thermostast, I like at least a 180 degree it will affect heater core temp. Keep us posted on the flush
 
Definitely a better flow in one direction. The water pump hose will go into the inlet that produces the best flow. Thanks.
 
Him is with heat!!!!

Through the defroster and lower center.... But have a draft on the passengers side when I pull the lever to 'heat' on the heat/vent cable. Obviously a linkage problem to be addressed later. I really wanted the defrost most.

Don't know for sure if it was the heavy duty flush or swapping the water pump hose to the bottom inlet and I'm not swapping it back to find out. :confused:

Anyway, glad I have some heat now.

Danka to all
 
congrats!! let your knees be warm. :chug:
 
Took the glove box out and looked at the linkage for the heat/vent circuit. Seemed to be working correctly. Noticed the flap door on the passenger side was not closing all the way. Removed the whole box and bent the flap door so that it would actually seal shut again and adjusted the right side adjuster.

All done and I expect it will work fine.

Now I just need to find the time to fix my oil leak and I will be pretty fault free.
 
feel free to run up and fix my oil leak too. :)
 
feel free to run up and fix my oil leak too. :)

I think I can fix mine, but laying on my back to do it is the problem. If I had a lift to work from it would be a piece of cake me thinks...

For some reason I get vertigo when I get under my jeep.

AND I drove the jeep to work this morning with 30 ish temps and it was adequate with no cold air in the cab. I think the Bronco motor would be helpful but not necessary enough to go cutting on the firewall.
 
So which direction is right?
Im repiping mine now and installing a new stat while i got it drained.
I never thought the direction mattered.
 
Someone on another thread had suggested there was a right and wrong way to attach heater hoses. Sounds like Duhwhat got good results from running the hose from the water pump to the lower heater pipe.

I can't find any reference in either of my manuals.
 
It doesn't matter.
 

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