Cool Heat At Idle, Hot Heat At Higher RPM's
- Thread starter PhillipA
- Start date
Heater core flushed. A little crud. Good flow both ways. The hose on top of thermostat goes to top of heater core. Bottom hose goes to bottom of heater core. At.idle on low fan defrost at 140 . Top radiator hose at 153 lower hose 134 . Upper heater core hose at169 lower heater core hose at 136. Fan on high defrost at 99. . Top heater core hose are 161 lower at 140. Upper radiator hose at 160 lower at 135. Metal hose that comes off water pump shows 174 and heater core hose that mounts to it shows 132. Is that bad?
As I worked my way up.with ir from base of metal pipe starting at bottom it was 176 and time I got to hose it was 136
Well, that's correct.
What's the temp on the thermostat housing where the temp sensor is?
Should be around 210.
What's the temp on the thermostat housing where the temp sensor is?
Should be around 210.
Maybe the blend door under the dash. I think it's vacuum operated. There is a vacuum line that goes through the firewall that cracks IIRC.
You can download a FSM at jeepslimited.com that will help you check it out.
You can download a FSM at jeepslimited.com that will help you check it out.
Unreal. Defrost 98 degrees on high. One speed back 105, one more back 125, on low 148. Should I have constant drip from ac evaporater lime comin.out from firewall on defrost?
I can turn vent selection to defrost/floor and heat goes to 120 with thermometer in defrost vent on high but change to straight defrost on high and it drops to 99 in defrost vent?????? Wth lol!!!
Results indicate a low coolant flow issue, evap will drain if there is humidity to remove.
Like I said earlier you have a flow issue. You don't have the correct volume of coolant going through the heater core.
With the fan on high the low volume of coolant is cooled much quicker, causing lack of heat.
Go drive it around for 20-30 minutes, get it up to temp , so we know the thermostat has cycled a couple times
Taking readings with the IR thermometer at the upper heater hose, if you check the temp in several places starting at the nipple off the thermostat housing and working you way back to the heater core, do you have a temp of at least 155-160 degrees?
Now do the same on the lower hose, but start at the heater core and work your way back to the coolant pipe off the water pump.
What are your temp readings?
What we are trying to do is determine if there is a lack of flow going to the core, a partial clog in the core, or a blockage going back to the water pump.
You don't know what the service history of your jeep was prior to buying it, That is why I suggested removing your thermostat and performing a coolant flush and back flushing prior to replacing the radiator.
It does not take a lot of rust or scale to partially clog a heater core.
I think I posted what you are saying earlier in this post. I did not remove thermostat because mechanic flushed it both times when he put 2 thermostats in
Defrost will be somewhat cooler as it runs AC to dry the air. Hence the water coming out of drain.
Theres 3 vacuum actuator under the dash. I think one is for the blend door. Maybe a broken vacuum hose under the dash? If the temp
Is constant in the hoses from the core, then the problem might be somewhere in the ubder dash unit
Is constant in the hoses from the core, then the problem might be somewhere in the ubder dash unit
I noticed when i had heater core changed that i had oily substance in passenger floorboard. Think it was Freon. I also noticed the same oily residue in floorboard after i flushed out heater core with garden hose. I had good flow both ways through hoses. I removed heater core hoses from front of engine so i think hoses are clear. Maybe metal tube to water pump is clogged. Can i take hose lose and use some kind of small brush to run through it and maybe clean it? I also mentioned in earlier post that i did not have pressure on top radiator hose, like it had no coolant in it. After i replaced radiator i had same problem until i took top radiator hose off and filled with coolant. Drove around for about an hour and checked and still had pressure in top radiator hose.
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