maddogs1965

So about 5 years ago i scored a 2000 G.C. with a blown motor, poor lady threw a rod threw the side of the block on the garbage 4.7, and could not afford a new motor.

So she signed the title over to me, and i installed a new motor in it with the intentions of selling the G.C. as soon as i had the Jeep running. Needles to say my dad fell in love with it, so i ended up giving it to him.

So it has been getting down to the -20's here in Truckee, and the G.C. has luke warm heat when it is that cold out.

About 3 year ago the blend door broke on the passenger side, so i removed the entire dash and heater system (such fun) and replaced both blend doors with the up graded doors from Jeep, i wish i would have know about Heater Treater flaps then. Anyway, when i replaced the blend doors, i also installed a new heater core just because it is a such a pain to access the heater core.
Also when i installed the new motor i also installed a new raditor since i drained mud out of the original one.

So i ran the diagnostic check on the heater assembley, and it came back with the code that the fresh air/resurculate flapper was sticking. So i removed the glove box, and i can see the flapper is opening and closing completely, and after i reset the code, it has not come back again.

So needles to say with a new raditor, a new heater core, 2 new blend flaps, and even changing out the thermostat just to make sure it was opening and closing properly, and even going as far as to block half of the raditor with a piece of cardboard, the heat still SUCKS when it is so cold out

I can grab both the heater hoses for the heater core, and they will burn my hand they are so hot. I can grab the upper hose which is also just as hot, but even with the new thermostat, the bottom hose is just barley look warm. The temp gauge is reading at 210*

So does anybody have any ideas, or does the heater system for the 2000 G.C. just suck? My 91 Cherokee will run you out of the cab no matter how cold it is outside.

One thing i might add, when the blower motor is on high, i can hear the fan blowing its little butt off, but it seems that the air coming out of defrost vents or on the dash vents does not seem to be blowing as hard as they should be.

Thanks in advance for any info or ideas.

Rick

kennzz05

u know in the back of youre mind,youre gonna end up taking the dash out again

i would think as far as the inside/outside door goes if it were working you could feel or read the difference with a thermometer between open and closed . cooler lower hose says either no flow or the fan is pulling all the heat out of the core it can, have you done this with no fan running are hoses still different temps wouldnt hurt to verify flow thru heatercore with a garden hose. and lastly is it possible the impellers on the water pump are worn and just not pumping properly. i know its pretty cold there in winter if it were summer it might be overheating (waterpump) thats all i got sorry

did you clean the fan blades while you had it out or look at them could be possible the ac coil is dirty preventing airflow

maddogs1965

You must have been reading my mind on pulling the entire dash and heater assembly out again

As far as the water pump, when i changed out the new thermostat, and had the bleeder nut removed, i could see the anti freeze flowing pretty good once the thermostat opend

the only reason i noticed the heat suck's so bad when it is so cold out, my dad is in the hospital with a broken hip, so i have been driving the G.C. to go down to Reno to visit him. If it does come to removing the heater box again or changing out the water pump, i will wait until summer when it is not -22 here.

kennzz05

start w/ the easy stuff flush the heater core see what ya got. i dont know are those things prone to getting airlocked and needing to be burped like the renix xjs? its doubtful

dave1123

I'd like to add my 2000 WJ will drive you out of the cab also. If both your heater hoses are hot, you're getting good flow thru the core. You must have an airflow blockage somewhere in the heater itself. Some of these vehicles have a cabin air filter in the cowl. It might be plugged with leaves or debris. The cabin air filter was an option.

maddogs1965

Thanks i will look for the filter, i can see were the air is sucked in on the outside cowl bye the window wipers, looks clear to me, but even when i go from fresh air to recirculate, there is barley a difference in the air flow......

Rick

dave1123

Take off the cowl cover and see if you can feel it sucking air on high blower. If you don't, you've got a problem with...wait! It doesn't change on recirculate? And it's not a blend door? Huh!

Did you replace the blower motor? I ran into a problem with a car once when we replaced a blower motor with one from the junkyard. The blower we got was from a standard heater and we put it in an A/C car. It acted the same. Ran very well but moved no air. We took it out and compared it with the old one. Bingo! the fan blade was 1/2" shorter so it bypassed a lot of air. I'm not saying this is your problem, but something to think about.

Redbarnrick

If you have a limited with separate temp controls, run both up to maximum, if that gets you heat your controls are faulty.

maddogs1965

Well since the temps have gone up to the low 30's & 40's instead of the negative 20's, the heater has been working fine and running me out of the cab.... I am thinking the poor Jeep is just not liking the negative temps

Then I came home after work Wednesday to the drivers front brake pads smoking, turns out the upper piston in the caliper must have hung up, so i removed the caliper and pushed it back in with a C clamp, brakes worked good Thursday, but was smoking again when i got home tonight, so i guess i am installing a new brake caliper tomorrow....i guess if it is not 2 things it is 3

dave1123

With my WJ, I spend a lot of time sitting in my jeep waiting for the newspaper branch to open so I can pick up my papers. I've found that after a while, when the temp is below zero, the engine temp drops below 200* because it's not making enough heat at idle. The heater temp drops also and I think it's because a lot of heat is lost from the hoses. Everything seems to work normally on the road or when the air temp is above about 20*

Also, that cold air coming into the heater takes more heat to warm up. This is just my observation and may have nothing to do with your problem, but I thought I'd throw it out there anyway.

Your brake problem is probably temp related also. The caliper bushings may be sticking and causing the caliper to "****", that is, one piston extending more than the other.

kennzz05

if you are unaware of the age of the rubber hoses going to the calipers replace them too they can swell internally and prevent the calipers from releaseing. i went thru the same thing replaced the calpiers and they still stuck hoses were the prob the whole time

maddogs1965

I am thinking not much of anything likes -20 temps, even my old 91 Cherokee does not put out quit as much heat when it is that cold. You have to consider @ -20 driving down the road you are still getting wind chill factors at what -30 to -40 hitting the raditor

At-least the temps have warmed up here, and the heater is working good again, i keep checking the heater controls too see if it is throwing any codes in the last 20 start up's and so far so good, everything seems to be working properly...

As far as the brake caliper, i guess after almost 13 years old, i am doing pretty good bye just replacing one caliper. Of course there are two different types for that year Cherokee... ATS, and a Chinese name i cannot pernounce and par for the course Napa gave me he wrong one the first time around. But so far so good....

Rick

dave1123

I don't want to start an arguement, but inanimate objects don't "feel" a wind chill. I've heard stories about car radiators freezing up while driving because of wind chill. but never actually seen a case that was verified.

Evaporation and loss of heat from the body is what causes wind chill.

jnicewan

True, I hate it when people factor windchill into inanimate objects. Could you imagine if those objects were affected by windchill, those 70MPH+ highway speed trips would freeze a lot of vehicles haha.

The only thing windchill can do to inanimate objects is cool them faster until they reach ambient temp and then they will stay at ambient temp. This is the same affect as blowing on that hot plate of food to cool it down faster.

dave1123

Absolutely! The few cases I've seen of radiators that froze on the NYS Thruway were not adaquatly protected and the drivers thought "I'll be alright as long as I don't shut it off and let it cool." WRONG!

Actually, they overheated because of no flow through the frozen radiator. We are talking -20* air temp and cars of 20 years ago.