JK only blowing cold air - JeepForum.com
 
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post #1 of 6 Old 10-28-2013, 10:27 AM Thread Starter
dayriesw
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JK only blowing cold air

I tried searching with no luck.

A friend with a 2011 jkur (70k miles) cannot get his jeep to blow hot air out. Last week he had his coolant system flushed. This weekend we removed his thermostat to confirm it was working, then top off the fluid and burped the jeep. After that, we let it warm up. The heater hoses got hot while it was idling. We had the fan on and adjusted all the controls and nothing but cold air blew out.

Any help would be great. Also, his coolant was redish brown, should he be concerned with that (some national chain auto shop did the flush)?


06 WK 5.7 Hemi Overland - Daily
87 MJ Chief 57k original miles... getting built in the backyard. 37s, waggy axles, D300, 6 speed, etc.

Gone - 05 LJ on 37s, 79 FSJ Chief on 38s, 85 CJ-7 on 31s
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post #2 of 6 Old 10-28-2013, 10:34 AM
442Wrangler
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The heater core sounds like it may need to be replaced or the system needs to be flushed again. You said the coolant was full correct?

2008 JK Rubicon
-255/80/17 BFG KM2s, 16/59 JKU springs, 2013 Rubi rims, RC stubby hybrid front bumper, XRC8 winch with synthetic line, RR evap skid, and more to come

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-Going to be restored and painted Plantation White and Presidential Red


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post #3 of 6 Old 10-28-2013, 10:45 AM
Jiblet
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Check to see if both heater core lines (in/out) are getting warm.

Sometimes the problem is the blend door. Search that for more info.

Color is unreliable indicator of coolant type. Get the store that did the work to confirm they used HOAT coolant. That's very important.

What prompted the coolant change? The heater problem? The OEM stuff should've been OK for 5 yrs/100k.
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post #4 of 6 Old 10-28-2013, 11:20 AM
nh1nh1
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had this happend to my XJ similar miles. Drove in the cold with it for several months (no heat) thinking it was going to be an expensive repair. Took it to a shop I trusted and they flushed the heater core and it fixed it only cost $20. lol They said the heater core was gunked up and blocking the heat from working.
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post #5 of 6 Old 10-28-2013, 12:11 PM Thread Starter
dayriesw
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Quote:
Originally Posted by 442Wrangler View Post
The heater core sounds like it may need to be replaced or the system needs to be flushed again. You said the coolant was full correct?
Yes. Fluid was full.

Quote:
Originally Posted by Jiblet View Post
Check to see if both heater core lines (in/out) are getting warm.

Sometimes the problem is the blend door. Search that for more info.

Color is unreliable indicator of coolant type. Get the store that did the work to confirm they used HOAT coolant. That's very important.

What prompted the coolant change? The heater problem? The OEM stuff should've been OK for 5 yrs/100k.
Both lines were hot to the touch. We could not heard the blend door open or shut. And it was blowing cold from all vents.

I will get him to check into the coolant. This problem prompted the change.

Quote:
Originally Posted by nh1nh1 View Post
had this happend to my XJ similar miles. Drove in the cold with it for several months (no heat) thinking it was going to be an expensive repair. Took it to a shop I trusted and they flushed the heater core and it fixed it only cost $20. lol They said the heater core was gunked up and blocking the heat from working.
Hmmm. thanks.

06 WK 5.7 Hemi Overland - Daily
87 MJ Chief 57k original miles... getting built in the backyard. 37s, waggy axles, D300, 6 speed, etc.

Gone - 05 LJ on 37s, 79 FSJ Chief on 38s, 85 CJ-7 on 31s
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post #6 of 6 Old 10-28-2013, 02:03 PM
jwmbishop
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My 11 JKUR did same at about 21.5 years 8K miles - i know enough to understand that when both hoses are hot coolant is flowing so it aint a plugged core. I dropped the glovebox door to get to the blend box - it was not cycling as I changed the heat setting so....

Went in to dealer and the blend door motor had broken - was operating motor but not door ... warranty in my case.

J Wm Bishop EA, ASADE
The wagon should, of course, be as light as possible, but strength should not be sacrificed to lightness, for on any but the regularly traveled roads, the wagon will get many a hard knock...
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