The heater was all fine before I had the spark plugs serviced. It was blowing out cold air, then a little bit warm air, then went back to cold air again. Tried all settings. Could it be the mechanics forgot to hook up something that they took off when service the spark plugs? Thanks.
My guess would be that the thermostat is stuck in the open position causing this problem.
SOURCE: 2002 GMC Yukon blows cold air from the front, rear works fine
check you antifreeze level and make sure its full
SOURCE: Heater
your blend doors are broken a common problem for the jeeps 1999-2004 e mail me at [email protected] and i will send you a link to a web site for a repair kit that will cost les than the 1200-1500 a dealer will charge to fix this
SOURCE: 2002 Jeep Liberty P0174 code and mech has changed the o2 sensor
Can't tell you exactly what is wrong but the one thing you said is of concern...Map sensor should not be full of oil. If it is, I'd want to know why. In finding the reason for that, you may also find the reason why you are having a problem.
Jeep uses two kinds of engine crank venting. you either have a pcv valve or an orifice controlled system. If either are obstructed it can overpressure the crankcase and cause all kinds of problems.
Years of experience tells me this isn't something I can guess at and be 100% sure I have the right answer but based on what you said, I'd look there first!
SOURCE: I have a 2002 Jeep Liberty Limited, 3.7 L motor.
Jeeps are notorious for having broken temperature control (Blend Air) doors. A malfunctioning Blend Air Door actuator probably caused it to break. The dash will have to be removed to replacethe door and the door actuator.
1. Using compressed air, blow out any dirt or contaminants from around top of spark plug. 
128 views
Usually answered in minutes!
Hi Ricky, Thanks for the reply. I found my coolant was low, added some coolant, and it's all fine now. Thanks again.
×