What would make your heat not get hot? - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Grand Cherokee & Commander Forums > ZJ Grand Cherokee Forum > What would make your heat not get hot?

Ring & Pinion's, Lockers, 4340 Axles, Install Kits, BaRockridge 4WD IS Taking Zone Offroad Suspension Lift Kits Engo winches available at www.rockridge4wd.com! Free shipp

Reply
Unread 12-11-2009, 09:42 AM   #1
WXman
Registered User
2001 WJ 
 
Join Date: Jun 2003
Location: Kentucky
Posts: 3,154
What would make your heat not get hot?

I have a new radiator, new heater core, new evap. core, new coolant. No leaks that I know of. Engine runs great. For some reason, my heat doesn't get hot anymore. This morning I drove it for 30 minutes to work and it was 17 degrees outside and the Jeep got somewhat comfy...but it never would get warm inside. Any ideas??

__________________
'92 YJ - heavily modded
'96 ZJ - heavily modded
'05 KJ CRD Limited - 370 lb./ft. from a 4-cylinder and trail ready. Pure awesomeness.
'11 Mango Tango JKU Sport - Mods
'12 Dozer JKU Sport S - 6-speed - ACE rock rails - Max Tow package - Daystar spacers - 33x12.50 Duratracs
WXman is offline   Reply With Quote
Unread 12-11-2009, 10:14 AM   #2
impuresoul2k3
Registered User
1993 ZJ 
 
Join Date: Mar 2007
Location: Nebraska
Posts: 565
Did you bleed the system? How's the coolant level?
__________________
1993 Grand Cherokee Limited, 5.2L
Modified/Slightly Ported Kegger
Air hat spacer
Modified Throttle body
Flowmaster muffler
impuresoul2k3 is offline   Reply With Quote
Unread 12-11-2009, 10:15 AM   #3
StrokedWJ
Web Wheeler
 
StrokedWJ's Avatar
2000 WJ 
 
Join Date: Oct 2007
Location: Asheville, NC
Posts: 3,000
Did you replace the thermostat? Does the engine temp ever reach the 195 mark?
__________________
2000 WJ 4.5L - Stroked, Locked, & Long-Armed

Click this -->Think you can beat me?
StrokedWJ is offline   Reply With Quote
Unread 12-11-2009, 10:22 AM   #4
EisBlade
Web Wheeler
 
EisBlade's Avatar
1999 WJ 
 
Join Date: Mar 2005
Location: Raleigh, North Carolina
Posts: 1,164
What happened for you to get all those new items in the first place? I don't see a thermostat listed. Go get a new one and compare it to yours. Keep in mind that sometimes even a new thermostats dont' work properly. "Stant" makes good ones.

If you are only getting warm and not hot, it could be that your thermostat is stuck in the OPEN position - not keeping the water in the engine long enough to heat up. Your engine isn't running at optimum operating temperature either.

When cold, a thermostat should be in the CLOSED position. As the engine heats up it begins to open and allow water to pass through to the radiator to get cooled. A good way to test thermostats at home is to put it in a pot of water on the stove and allow the water to reach boiling. Once boiling, pull the thermostat out with a set of metal tongs or large spoon and check to see if it is in the OPEN position.
__________________
.
JT
Harley-Davidson Touring Group [35K members]
The largest forum on Facebook for Road King and larger touring models.


Disclaimer:Not responsible for men of weak character.
EisBlade is offline   Reply With Quote
Unread 12-11-2009, 12:30 PM   #5
YJMCBoy
Registered User
2010 JK Wrangler 
 
Join Date: Mar 2005
Location: Halifax, Massachusetts
Posts: 350
Quote:
Originally Posted by EisBlade View Post
A good way to test thermostats at home is to put it in a pot of water on the stove and allow the water to reach boiling. Once boiling, pull the thermostat out with a set of metal tongs or large spoon and check to see if it is in the OPEN position.
and wash the pot out before your wife decides to use it to cook dinner and you get funny tasting ziti.
__________________
2010 JK 4-Door Unlimited Sport- Soft top, V6, 6-speed standard, bone stock for now
YJMCBoy is offline   Reply With Quote
Unread 12-11-2009, 12:43 PM   #6
the88thpianoman
Registered User
2003 WJ 
 
Join Date: Apr 2008
Location: Tampa, FL
Posts: 5,252
Could be a blend door or AC actuator issue as well, if the engine is reaching proper running temp.
__________________
2003 WJ in Jeep Green Metallic, 4.0/242/4.10's. 4" Teraflex springs w/ RE monotube shocks and IRO short arms, cheap intake w/ amsoil filter, 2.5" hi flow cat and back exhaust, lots of lights and other misc crap.

Check out my build thread here: Life lessons and budget build
the88thpianoman is offline   Reply With Quote
Unread 12-11-2009, 04:56 PM   #7
EisBlade
Web Wheeler
 
EisBlade's Avatar
1999 WJ 
 
Join Date: Mar 2005
Location: Raleigh, North Carolina
Posts: 1,164
OP, what is the highest temperature your gauge reads once the engine has ran long enough to be at its hottest temperature when idling?
__________________
.
JT
Harley-Davidson Touring Group [35K members]
The largest forum on Facebook for Road King and larger touring models.


Disclaimer:Not responsible for men of weak character.
EisBlade is offline   Reply With Quote
Unread 12-12-2009, 07:06 AM   #8
WXman
Registered User
2001 WJ 
 
Join Date: Jun 2003
Location: Kentucky
Posts: 3,154
Well my rad had a leak early this year so I got a new one. Then in the Summer my AC wouldn't hold a charge so I traced the leak to the evap core. Changed the heater core while I was in there. The coolant obviously is all new...the level is fine with no leaks now. My engine runs at 220....the very middle of the gauge. I did not replace the water pump or t-stat yet. But if it runs at normal temp then that should be ok right? The blend doors seem to blend the air properly. I guess it has to be the temp control dial..right?
__________________
'92 YJ - heavily modded
'96 ZJ - heavily modded
'05 KJ CRD Limited - 370 lb./ft. from a 4-cylinder and trail ready. Pure awesomeness.
'11 Mango Tango JKU Sport - Mods
'12 Dozer JKU Sport S - 6-speed - ACE rock rails - Max Tow package - Daystar spacers - 33x12.50 Duratracs
WXman is offline   Reply With Quote
Unread 12-12-2009, 07:15 AM   #9
ZJPunk98
Registered User
2002 WJ 
 
Join Date: Oct 2005
Location: North Kingstown, Rhode Island
Posts: 2,065
Well if your engine is running at the correct temp, then your water pump must be fine and is circulation the coolant.

This could be a blend door problem. Especially since its cold out (or really hot out), you will notice the malfunctioning blend doors the most. They will allow to much cold air to enter the system, thus over cooling your hot air. This could be why you have only warm air.
__________________
Erik

98 ZJ 5.2L JGC Limited Sold
02 4.7L HO JGC Overland
ZJPunk98 is offline   Reply With Quote
Unread 12-12-2009, 09:29 AM   #10
steeleman3
Registered User
1993 ZJ 
 
Join Date: Oct 2009
Location: Denver, CO
Posts: 343
I have the same problem, never seems to blow hot only warm air at the most. Only my temp guage is almost always at its lowest point, not in the middle
__________________
Big Gulps huh? Alriight! Welp, see you later!
steeleman3 is offline   Reply With Quote
Unread 12-12-2009, 09:32 AM   #11
97DCZJ
Registered User
1997 ZJ 
 
Join Date: May 2009
Location: Long Island
Posts: 2,181
heater core. to replace it, you need to rip your entire dash apart
__________________
1997 Grand Cherokee Orvis: V8 5.2L, stock.
(Sold) 1998 Cherokee Sport: 4.0L I6, Stock.
(Sold) 1990 Cherokee: 4.0L I6, 4.5" Lift, 33" BFG's.
(Sold) 1997 Grand Cherokee Limited: V8 5.2L, 2" BB, 31" Dick Cepeks.
(Sold) 1999 Grand Cherokee Laredo: Build Thread; V8 4.7L, Stock.
(Sold) 1996 Grand Cherokee Laredo: Build Thread; V8 5.2L ,3.5" lift, 32" Tires
97DCZJ is offline   Reply With Quote
Unread 12-12-2009, 11:56 AM   #12
Tiggerrrrr
Registered User
1995 ZJ 
 
Join Date: May 2008
Location: Fall River, Ma
Posts: 579
Quote:
Originally Posted by mrflandy3 View Post
I have the same problem, never seems to blow hot only warm air at the most. Only my temp guage is almost always at its lowest point, not in the middle
Buy a new 195 degree thermostat. It sounds like yours is too low of a temp or it's stuck open.
__________________
'95 ZJ Limited 4.0
2.25" BB , 31 10.5 15 Treadwright MTG's on Black Rock steelies
Everything "pimpin' Gold" REMOVED!


Looking for a REAR tow hook and bracket!
Tiggerrrrr is offline   Reply With Quote
Unread 12-12-2009, 06:51 PM   #13
EisBlade
Web Wheeler
 
EisBlade's Avatar
1999 WJ 
 
Join Date: Mar 2005
Location: Raleigh, North Carolina
Posts: 1,164
Quote:
Originally Posted by mrflandy3 View Post
I have the same problem, never seems to blow hot only warm air at the most. Only my temp guage is almost always at its lowest point, not in the middle
EDIT: x2, a thermostat is needed. (I type too slow)

The OP's, well, if it's reaching correct operating temp then his thermostat working fine. The dash will have to be pulled (passenger side) and, like 96DCZJ mentioned, the heater core needs checking. If it gets hot when the engine reaches normal temp. then that works. Air blows across, warms, and gets blown inside. After that, focus on the blend doors. They may be stuck open and allowing too much cool air to pass into the cabin area.
__________________
.
JT
Harley-Davidson Touring Group [35K members]
The largest forum on Facebook for Road King and larger touring models.


Disclaimer:Not responsible for men of weak character.
EisBlade is offline   Reply With Quote
Unread 12-13-2009, 12:07 AM   #14
97DCZJ
Registered User
1997 ZJ 
 
Join Date: May 2009
Location: Long Island
Posts: 2,181
Just actually read the original post, and noticed you mentioned you installed a new heater core, so ignore my last post.
if your temperature isn't at 190 at the least, bad thermostat. I was running a 160* thermostat up until last week, and it only blew warm air because the engine wasnt hot enough to blow hot air.
__________________
1997 Grand Cherokee Orvis: V8 5.2L, stock.
(Sold) 1998 Cherokee Sport: 4.0L I6, Stock.
(Sold) 1990 Cherokee: 4.0L I6, 4.5" Lift, 33" BFG's.
(Sold) 1997 Grand Cherokee Limited: V8 5.2L, 2" BB, 31" Dick Cepeks.
(Sold) 1999 Grand Cherokee Laredo: Build Thread; V8 4.7L, Stock.
(Sold) 1996 Grand Cherokee Laredo: Build Thread; V8 5.2L ,3.5" lift, 32" Tires
97DCZJ is offline   Reply With Quote
Reply
Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.