No HEAT/NOT Overheating
01-06-2012 | 11:52 AM
#31
Senior Member
Joined: Nov 2011
Posts: 561
Likes: 0
Model: Cherokee
Had no heat in my '99. Back flushed the heater core with PB blaster. Went from none to mediocre heat. Did it again, great heat. Whenever I fill any system, I squeeze the upper hose to burp air. Cap it when it gets full, fill overflow, go for a drive.
But I back flushed with PB twice, and normal flushed with a garden hose on full. Chunks came out both times. If you pull the upper heater hose while running(cold) it should shoot to the firewall. Pull the lower heater hose off the Heater core it should shoot to the a/c compressor. If it don't hit firewall, pump sucks. If it don't hit the a/c, flow through the core sucks and needs flushed or replaced. Got 248k miles, 2nd pump at 198k two years from PO records. Just an 'old Chevy' mechanic learning the arts of Jeep.
But I back flushed with PB twice, and normal flushed with a garden hose on full. Chunks came out both times. If you pull the upper heater hose while running(cold) it should shoot to the firewall. Pull the lower heater hose off the Heater core it should shoot to the a/c compressor. If it don't hit firewall, pump sucks. If it don't hit the a/c, flow through the core sucks and needs flushed or replaced. Got 248k miles, 2nd pump at 198k two years from PO records. Just an 'old Chevy' mechanic learning the arts of Jeep.
01-06-2012 | 12:21 PM
#32
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
Most t-stats don't have a bleeder hole as they don't seal air tight......but the bleeder hole becomes a moot point the 1st time the t-stat opens. When the t-stat opens, air moves on to the highest point......the rad cap (open system) or the bottle (closed system).
I don't think the caveat is the bleeder hole.........but rather the owners and their maintenance (or lack of). With regard to some of the posts lately, one can read between the lines and see "I haven't raised the hood in 6 months to a year, why is my XJ...................".
I don't think the caveat is the bleeder hole.........but rather the owners and their maintenance (or lack of). With regard to some of the posts lately, one can read between the lines and see "I haven't raised the hood in 6 months to a year, why is my XJ...................".
01-06-2012 | 10:00 PM
#33
Thread Starter
CF Veteran
Joined: Apr 2011
Posts: 2,080
Likes: 0
From: Dayton Ohio
Year: 1998 classic
Model: Cherokee
Engine: 4.0!!
I topped it off this morning and the heat is very hot now. The problem was air trapped in the system. The only thing that wasn't replaced was the heater core. I bought this jeep from a guy that clearly didn't know how to maintain a vehicle. The t-stat was stuck closed which caused a leak in the radiator. Then he added a jar of some stop leak. Which only clogged the system. The end solution was flush and burping the system.
01-06-2012 | 10:40 PM
#35
Thread Starter
CF Veteran
Joined: Apr 2011
Posts: 2,080
Likes: 0
From: Dayton Ohio
Year: 1998 classic
Model: Cherokee
Engine: 4.0!!
Im going to try and make this easy to read and straight forward!
-99 cherokee 4.0L
-Bought a month ago and has since had heat issues/leaks
-Replaced the bad radiator. still no heat
-Week later the radiator ruptured. looked further into it and the thermostat was stuck closed.
-Replaced the thermo and a new radiator. i still have no heat. ive tried a few ways to bleed out the air but im not getting good results.
-I can top it off at the radiator and fill the reservoir and drive it and check it later and it needs more coolant. there are no known leaks and it doesn't smoke to my knowledge. nor does the temp gauge get over op temp. NO HEAT.
-i have started it cold with cap off and let get to op temp with cap off. At first it burps out air then it just over flows after a bit.
Question is whats the best way to bleed the air out or to see if i have a bad head or gasket?
-I did notice when the engine was warming up with the cap off, fluid to the top.... there were tiny air bubbles comming out real tiny ones. i wasnt sure if they were just air bleeding out or if its a sign of a bad head or gasket.
-I cannot tell if the coolant smells like exhaust or not.
-The system is pretty dirty like a brown rust color. I know it needs flushed. ANY THING WILL HELP!! This is the wife's daily driver i need to figure this out!
-99 cherokee 4.0L
-Bought a month ago and has since had heat issues/leaks
-Replaced the bad radiator. still no heat
-Week later the radiator ruptured. looked further into it and the thermostat was stuck closed.
-Replaced the thermo and a new radiator. i still have no heat. ive tried a few ways to bleed out the air but im not getting good results.
-I can top it off at the radiator and fill the reservoir and drive it and check it later and it needs more coolant. there are no known leaks and it doesn't smoke to my knowledge. nor does the temp gauge get over op temp. NO HEAT.
-i have started it cold with cap off and let get to op temp with cap off. At first it burps out air then it just over flows after a bit.
Question is whats the best way to bleed the air out or to see if i have a bad head or gasket?
-I did notice when the engine was warming up with the cap off, fluid to the top.... there were tiny air bubbles comming out real tiny ones. i wasnt sure if they were just air bleeding out or if its a sign of a bad head or gasket.
-I cannot tell if the coolant smells like exhaust or not.
-The system is pretty dirty like a brown rust color. I know it needs flushed. ANY THING WILL HELP!! This is the wife's daily driver i need to figure this out!
01-14-2012 | 10:36 PM
#37
Newbie
Joined: Oct 2010
Posts: 6
Likes: 0
Model: Cherokee
I've been having a go round with my jeeps heat. Bought an 01 Cherokee that had a radiator leak. Replaced the radiator and flushed the system several times. Heat still not good. Replaced the tstat and flushed again, heat better. The hose going to the heater box is almost to hot to hold at running temp, while the return hose is warm, not as hot. I lose all heat when the jeep is at idle, but as soon as my rpm's hit about 1500 my heat starts to work. Gonna change the water pump and flush again.
12-23-2017 | 08:51 PM
#38
Newbie
Joined: Dec 2017
Posts: 1
Likes: 0
Model: Cherokee(SJ)
99 jeep grand Cherokee
I got a jeep grand Cherokee I change my heater core I change my thermostat I change my blend doors I bleed the coolant and I still have no heat the top hose gets hot but the bottom hose doesn't get that hot I let it run for a hour and I still can take the radiator cap off I don't know what's else to do any suggestion
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