Are both heater hoses getting hot? Are you experiencing any unexplained coolant loss?

 

Yes both top and bottom hoses are getting hot. However the top hose never really gets firm at all like the system is pressurizing. No unexplained coolant loss either. Head gasket tests out as well. The thermostat I purchased has a small weep hole positioned at 12 o clock on the stat. Could this be an issue ?

 

No, the jiggle valve is supposed to be there and it is installed correctly.

At this point, I would remove both heater hoses from their fittings at a convenient to get to location when the engine is cold and off. Then I would put mild garden hose pressure through the top hose and observe the flow through the bottom hose. Remember the system is only used to 16 PSI or less, while household water pressure can be 100 PSI without a pressure control valve, or about 60 PSI with one.

If you have a heater water control valve, do this downstream of it so that it is not a factor during this test.

You can also purchase a Prestone kit to help you flush the system. I wouldn't do the whole thing yet, just the heater hoses.

 

^^^^^^^^As stated, remove/test the stat. Once removed, u'll instantly see if it's open or not. If it's open, get your receipt and have it warranted. If it's closed, test in a pan of water, on top the stove using a cooking thermometer. Do not toss a stat into boiling water. Takes about 45 minutes to pull, test and re-install......way less time than this thread. LOL

 

So on the heater core side or on the engine side ? Sorry I am just not totally following you.

 

I always put cardbored in front of the radiator for Wisconsin winters.. And for your misfire, if you have a multimeter look up with the ohm resistance should be and check all your plug wires. Your engine can do all sorts of weird things if a wire is bad.

 

You want to disconnect one hose just past the control valve if you have one.

That is the supply hose to the heater core. That is the one you put the water hose to.

Disconnect the other hose and point it down towards the ground. This is your discharge.

If you have a good flow and no gunk comes out, hook everything back up and start your engine. Put the heater on full hot. Go back to the engine and look at the water control valve. Make a note of the position of the lever. Then move the control to full cold. The lever should move as far as it can the other direction to stop water flow to the core.

 

Yes the heater core has great flow and no gunk, its brand new lol. The heater control valve is also functioning as it is supposed to.

It is not as if the engine is reaching op temp and the heat is poor. It is that the engine is never reaching and maintaining the proper 195*-210* operating range therefor is never producing optimal heat. If i let it sit in the driveway for a half an hour and idle it will warm up to a tick under 210 and blow some very acceptable heat. As soon as I start driving the temp lowers and so does the heat output.

 

Yes the heater core has great flow and no gunk, its brand new lol. The heater control valve is also functioning as it is supposed to.

It is not as if the engine is reaching op temp and the heat is poor. It is that the engine is never reaching and maintaining the proper 195*-210* operating range therefor is never producing optimal heat. If i let it sit in the driveway for a half an hour and idle it will warm up to a tick under 210 and blow some very acceptable heat. As soon as I start driving the temp lowers and so does the heat output.

 

From what you said so far, it really sounds like the thermostat is stuck open. It may be new, and may be MOPAR, but ***** happens and you might have got a defective one. Pull it out and check.

Check that it opens at the right temp by putting it in a pot with water alongside a thermometer that goes to 212 or more and bring the water to a boil. When the stat opens, note the temp at which it does.... Do this if it is closed when you take it out. If it is open when you take it out then you need to get a new one.

 

I suppose you are right.

 

Sounds like an echo in here. LOL Do not expose the stat to boiling water.....it's not exposed to boiling water inside ths motor.

 

Water boils at 212*F at sea level pressure. A normal XJ runs really close to that most of the time.

 

Lots of Jeep folks here say their jeep runs at 200-210. The OEM stat is 190. 212 isn't going to hurt the stat one bit.

Plus, once the stat being tested opens they can take the pot of water off the heat...

 

In a properly functioning automotive cooling system, coolant will not boil until somewhere north of 260F. Again, do not expose the stat to boiling water. Coolant does not boil inside a motor until it reaches +260F.

A proper test of the stat can be done without water reaching 212F.