What would make your heat not get hot? - JeepForum.com

 
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post #1 of 14 Old 12-11-2009, 10:42 AM Thread Starter
WXman
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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??


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post #2 of 14 Old 12-11-2009, 11:14 AM
impuresoul2k3
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Did you bleed the system? How's the coolant level?

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post #3 of 14 Old 12-11-2009, 11:15 AM
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Did you replace the thermostat? Does the engine temp ever reach the 195 mark?

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post #4 of 14 Old 12-11-2009, 11:22 AM
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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.

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post #5 of 14 Old 12-11-2009, 01:30 PM
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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.

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post #6 of 14 Old 12-11-2009, 01:43 PM
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Could be a blend door or AC actuator issue as well, if the engine is reaching proper running temp.

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post #7 of 14 Old 12-11-2009, 05:56 PM
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OP, what is the highest temperature your gauge reads once the engine has ran long enough to be at its hottest temperature when idling?

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post #8 of 14 Old 12-12-2009, 08:06 AM Thread Starter
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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?

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post #9 of 14 Old 12-12-2009, 08:15 AM
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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.

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post #10 of 14 Old 12-12-2009, 10:29 AM
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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

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post #11 of 14 Old 12-12-2009, 10:32 AM
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heater core. to replace it, you need to rip your entire dash apart

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post #12 of 14 Old 12-12-2009, 12:56 PM
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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.

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post #13 of 14 Old 12-12-2009, 07:51 PM
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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.

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post #14 of 14 Old 12-13-2009, 01:07 AM
97DCZJ
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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.

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