nmunlin

Noticed last night while driving home that my thermostat was not getting up to normal temperature, 2011 JKU with 75.5k miles. Also noticed no heat from heater. Checked both lines for heater core and they were both hot. Coolant level hasn't changed. This morning when driving to work, the thermostat got near normal temp and then would drop back to the quarter line. Never gets above halfway. Besides the thermostat being stuck open or the temperature sensor being bad, what else should I look into? Also got a CEL light this morning and the code was p0128

Sixty4x4

Sounds like the thermostat requires replacing. Lucky it stuck open not closed!

nmunlin

Would this be causing no heat issue as well? Yeah I'm thinking very fortunate it's open and not closed as well.

Sixty4x4

If your temp gauge is like mine I get some heat before the gauge even gets to 1/8 from cold. Just starts moving and voila - heat. Need it here for day highs at -30C recently. Not sure if the low temp is your heat problem but I would recommend getting the engine side cured first then go from there.

nmunlin

Thanks much. Don't need heat here in Louisiana for the near future. Thinking maybe the actuator may be stuck. It happened before when the floor vent came loose and was stopping it but I checked all that last night and it was still all attached where it needed to be. Will be able to dig into it more tonight. You are correct though, I'm gonna worry more about the engine side of life first

resharp001

considering not expensive and easy to do, a lot of will change that coolant temp sensor at the same time we change thermostats.....and always best to stay OEM on those.

It sounds like you're getting hot coolant to and from the heater core since both lines are hot. Kinda makes me think need to investigate the blend door.

nmunlin

Quick question, I stopped at O'Reilly to get something and they are telling me I'm supposed to have pink coolant. I have orange right now. When he searched the system it said yellow. So which should it be?

Jay2013jk

( If memory is correct) 2011 JKs use HOAT.. Mopar 68048953AB Standard HOAT 07-12 Jeep Wrangler JK
Color is not the identifier.. read label on coolant. Different mfgs use different color dyes .. Just look for HOAT .. There are AFtermarket brands that are HOAT; ..
If your system was not flushed and you are not sure of what is in yours; then a Flush might be in order.

EHarris

Hit those bolts for the thermostat housing with PB blaster a for a few days before you attempt to take that apart. Careful when you snug it back up.

nmunlin

that'll definitely happen my next day off and your memory is very accurate from what I've read, it was the color throwing me off and then making me think I had the wrong stuff in it that got my worries. Thanks for clarifying though I didn't know that about the dyes, thought the dye was the type

Yeah I read 250inch pounds but that seemed really high, then I read 105. I set it to 105 and it was getting too tight for my liking so I stopped. Will make sure no leaks. I'm gonna post a pic of the throttle body if it'll let me, just know I've only owned this a few months so don't hate on me too much