Heater warm up time.

[Travis]

How long should it take for the heater to start blowing hot air? Granted, it has been around 10° for about 3 days, but my TJ heat is shit and has been recently. It takes at least 30 minutes to start blowing mild heat. What are some things I can check to figure out why? People say it's the soft top, but it has been hot in the past, so I know the heat works.

 

[Jeep9748]

I would back flush the heater core. If that doesn't help, look and see if anything is built up in front of the core. Its not bad to check, you can use an inspection mirror and look in the intake side under the cowl. Lastly, check that the flap arm is moving the door between the heater core and A/C (if on the vehicle) fresh air.

 

[Travis]

I have to admit, I don't know what back flush the heater core means.

 

[Travis]

I watched a couple videos, that is easy enough to do. Gonna get that done asap. Hopefully it helps.

 

[Jeep9748]

From experience, make sure you back flush at the core....and flush both ways....also as I found out the hard way. The guy I bought my jeep from had the lines to the heater core reversed. you wouldn't think it makes a difference, but after a week in North winter a couple years ago, IT DOES!! made a HUGE difference. going from warm breeze to cooking eggs inside the cab. That was my soft top Jeep.

 

[Jerry Bransford]

It could be a clogged heater core as mentioned above. But if your engine isn't warming up quickly either, your engine thermostat could be bad (stuck open) too. Replacing the thermostat with a new 195 degree NON-FAILSAFE thermostat like from Stant would fix both issues.

 

[Chris]

X2 to Jerry's advice.

My Jeep warms up really quick, usually in a minute (or two on the coldest of days).

 

[Head Lice]

x3
Thermostat stuck open .....

 

[Ahoragi]

My warms up by engine temp. The warmer the engine, the warmer it is inside.

 

[Sunder]

Mine takes about 10 min to heat up in winter. Winter today being around -30'C (which is about -22'F for my southern friends).
Takes about a minute in summer.
Most likely either a stuck thermostat or a clogged heater core, as mentioned above.
Or...your heater "door" is stuck mixing in too much outside air.

For heater core check, pop the hood and touch the 2 hoses going into the firewall to your heater core. (2 black rubber hoses near your battery going through foam towards your cab). (these are also the hoses you'll disconnect if you are going to try and clear your heater core with compressed air or cleaning solution - ONLY if you KNOW the heater core is the issue, and you know what you're getting into).
If both hoses are cold, then your issue may be your thermostat.
If one hose is greatly hotter than the other, then the issue may be a clogged heater core.
If both hoses are really hot...then maybe heater door mixing in too much cold air?

Note: there are thermostat's that turn on/off at different temperatures. So even if the thermostat is not stuck, it's possible that it's cooler the engine earlier than the factory setting. I had previously installed one that did that, then was confused why I didn't get as much hot air as I used to...I now use the factory temperature thermostats

 

[billiebob]

So same temperature here today, 10F. It took 4 minutes to start melting the windshield snow, At 10 minutes the temp gauge was at normal, And at 14 minutes I was turning the heat down.