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Heater hose route

Heater hose route

WillyWillCJ7

Jeeper
Posts
4
Thanks
0
Location
Ocala, FL
Vehicle(s)
1983 CJ7 258, 1993 YJ 2.5L both with 4” of lift
When my dad owned my Jeep he bypassed the heater core when it cracked. The water pump has 3/4” hose coming off but the new core (and old) have 5/8” fitting. Can’t find proper hoses online or at parts store....any advice would be fantastic. ‘83 258cu in.
 
Thanks, you wouldn’t happen to know which hose goes to top/bottom of the core would you?

Top to water pump. Bottom to water jacket on intake manifold
 
Get the 5/8" ID straight hose.
Put the one end in boiling water and it will stretch enough for the 3/4" fitting.
LG
 
That adapter is exactly what I used when installing new heater lines. I did not have a line to the manifold though.

Do the water jackets in the manifold do anything besides tell the temp and have a knock sensor?
 
Do the water jackets in the manifold do anything besides tell the temp and have a knock sensor?

Keeps fuel/air mix warm after the manifold heater shuts down and keeps the intake from getting hot.
 
Last edited:
Keeps fuel/air mix warm after the manifold heater shuts down and keeps the intake from getting hot.

So the manifold heater is just for start-ups until the water gets warm. Ok, is the heater plugged into a computer or just a 12V source?
 
Works from a relay. Not connected to computer.

Here are a couple of diagrams. In a couple of the FSM diagrams CZ C100 label is the fuse block.

Manifold Heater Wiring.webp

Manifold heater only.webp

6 cyl man htr.webp

6 cyl choke heater manifold.webp
 
Works from a relay. Not connected to computer.

Here are a couple of diagrams. In a couple of the FSM diagrams CZ C100 label is the fuse block.

That's beautiful, thank you so much!!
 
Ran across a pretty good solution for the heater hose from the thermostat housing to the manifold so will share it here.
Attempting to fit a straight hose from point A to point B wasn’t working out so well and I couldn't find a direct fit replacement.

I had a new molded heater hose on the shelf for my wife’s Subaru.
Each end had appropriate bends to navigate half of the route.
I was able to cut a small section out of the middle and connect the center with a 3/4” brass straight fitting.
Complete solution about $12.

2005 Subaru Heater Hose for “thermostat to manifold” Continental # 64332 about $9 from Rockauto.
¾” x ¾” straight brass hose fitting # 818281 from Lowes, about $2.

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