If you're going to get your hands dirty and spill a lot of antifreeze anyway, it makes sense to do these at the same time.
Your primary problem is likely just the thermostat, so if you're on a tight time or $ budget, the thermostat is your first priority.

 

I put an Amazon link in one of my posts in this thread. As also stated, a dealership is a good option but probably more expensive.

 

One more question, I know there is a LOT of controversy about which hole in the firewall/heater core is the inlet and outlet due to both being labeled differently in books/online. How do I tell which one is the inlet/outlet on mine/?

 

They are two different size hoses that go back to the motor.

 

My notes have the top Heater Core connected to the t-stat with the 2 angle hose and the bottom H/C connected to the water/pump with the 1 angle hose.
I bought the hoses already and will be doing the HCV delete on my 95 as soon as the weather cooperates with me. (We have about 10" of snow on the ground right now.)

 

People mentioned a vacuum advance, where is it? Also what DOES the hvc even do and what does that wire coming off the top do, what do I do with this?

 

The HCV controls coolant entering the heater core depending upon your temp selector. So when you have it all the way to "hot", it opens fully and when it's all the way "cold" it closes. It's vacuum operated - that's the little hose coming off the top.

In a 97+ XJ, the coolant flows through the heater core at all times, which is good since stagnant coolant sitting in the heater core can cause it to rot and leak and it's a monster of a job to replace. The air flow between hot and cold is entirely regulated by the blend door. In the pre-97's, there is the same blend door, which is completely sufficient for regulating between hot and cold air, just they over-engineered it with the additional valve.
So 2 downsides to having the HCV - Stagnant coolant in summer causing your heater core to rot AND - plastic HCV is prone to breaking.
There's no benefit to having it.

I was told that the best way to deal with the vacuum hose is to plug it with a screw with a washer and silicone. A healthy amount of silicone is probably sufficient. You basically need to make it air-tight so it doesn't cause a vacuum leak and then tie it off to the side with zip-ties.

 

Thanks Pat, so does that mean by removing the HVC my temp control will not matter any more because its either on or off?

 

Temp controls should work normally. You shouldn't notice any difference in actual operation.

 

What does the HVC actually do then? What controls the temp and speed of the heater? So a couple of clarifications: Why should I get rid of it? 2. The two hoses only hook up to the right size, ie impossible to not hook it up wrong?

 

The HCV controls the coolant flowing into the heater core. The blend door controls how much cool and warm air enters the cabin - hence the name "blend door" as it blends the hot and cold according to the selected temp.
Put simply - when you select "Full cold", the HCV cuts off the coolant flow to the heater core AND the blend door only allows cool air to enter the cabin. When you select "Full Hot", the HCV allows full coolant flow into the heater core AND the blend door allows only warm air to enter the cabin.
So the -result- of the operation is exactly the same. Jeep engineers recognized that the HCV was pointless over-engineering and removed it in 97+.

The "speed of the heater" is related to the fan - it uses a resistor to adjust the fan speed according to the selected speed.

You should get rid of it because it is 1 - Prone to breaking. and 2 - Leaves stagnant coolant in your heater core during warm weather (in other words, whenever you use "full cool" temp setting) which damages the heater core.
It's your Jeep though, so it's up to you.

I will be eliminating it because I don't want my heater core damaged. I live in the North East and I like having heat and I want my heater core to remain functional.

The pre-formed hoses are almost impossible to hook up incorrectly. As I mentioned earlier, my notes have the "double angle" hose going from top heater core pipe to T-stat and bottom heater core pipe to water-pump with the "single angle" hose.

 

Thanks for your writeup Pat. When you say the pre-formed hoses, are the two pipes not the same size on each (in other words why can't I just use heater hose to complete the hookup?)

 

You can use normal heater hose. You need both 3/4" and 5/8". Here is what it looks like with normal heater hose.



If you want a cleaner look, you go with the pre-bent hose. But in the end, they both do the exact same thing.

 

Or you can buy the right length hoses and relocate them away from the valve cover and over to the fender well. I did this thinking there was already enough heat at the engine anyways. Have no idea if it helps though.

 

Well heres the update, went to dealership to buy the mopar, and it was around 28$, but it says 'motorad' on it, which made me wary as my motorado 'fail safe' was the one that had broke.

It is unclear but apparently mopar uses/makes motorad? I am wary honestly.

I take my old theremostat out: its the motorad 'fail safe' and it was broken it had 'failed' open, meaning my truck literally never warmed up. So glad I do have at least one issue fixed, but again, paranoid about putting a trash motorado in it (DESPITE THE BOX SAYING MOPAR)

Flushed my core out, and ZERO problems here, it flowed clean both ways.

One issue: that HVC appears to be actuated by the control in the dash, but when I had friend move it, it moved once, but (without the fluid it lost vacuum?) it never moved again. Is this because there is no fluid in there? It looks like its driven by a rod, of which it does not sit on it very well, was there perhaps a retaining clip or something that is gone?

I don't want to delete this yet unless I have to, can I just put fluid in and shove this back into the right position?