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Dan
Dan, Technician
Category: Dodge
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Experience:  2 Year Auto Diploma and Database Access
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2009 avenger is over heating when heat is turned on car

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2009 avenger is over heating when heat is turned on car cools to normal. I heard there are two thermostats on this modle a primary and a secondary on the block. The primary was changed secondary was not. Both upper and lower radiator hoses get hot and seem pressurized. Could the secondary thermostats be faulty? Maybe water pump needs replacing? I figured if both hoses are hot the thermostats should be operating properly. Any thoughts?
JA: Has the vehicle ever overheated? And when was it last serviced?
Customer: Never overheated before. When this episode started I took it to a reputable mechanic shop and they are the ones that changed the primary thermostate. Ran ok for a few days then started overheating again
JA: Are you fixing your Avenger yourself? What have you tried so far?
Customer: i will be fixing it myself. Have not tried anything yet. Wanted some feedback before throwing parts at it. I thought I would start by burping the system.
JA: Anything else you want the mechanic to know before I connect you?
Customer: No

Hello, my name is ***** ***** I'm here to help get your problem solved.

Does it overheat when going down the highway or only at slow speeds and stops?

Customer: replied 8 months ago.
Have not drove it on the highway . It started in normal city driving

What engine do you have?

I'm assuming it overheats at idle too? Thanks.

Customer: replied 8 months ago.
4.2 and yes overheats at idle

Check the temperature of the radiator across the core. Any distinct temperature difference indicates a clogged radiator. Based on symptom it sounds like you likely have a clogged radiator. But fact it ran good for a few days after having thermostat replaced tells me your head gasket could be leaking, pushing air into coolant. So so having thermostat replaced got all air out of system which is why it ran good for a few days but now air is back in system causing it to overheat. Check for air in coolant, if there then I'd recommend doing a block test which checks for exhaust gas in the cooling system. If no air in system and radiator doesn't seem to be clogged then I'd continue with replacing the secondary thermostat. Let me know if you have more questions, thanks.

Dan and 2 other Dodge Specialists are ready to help you
Customer: replied 8 months ago.
Ok I burped the system and needed to add about 1 ltr of coolant drove around for about 30 min and no overheating. Turned a/c on and heat no issues with either. Pulled in driveway and opened hood with car still running and noticed air bubbles coming into the coolant tank. One small bubble after another not rapid but in one second I intravols.

It sounds more like a head gasket issue, next step is a block test which checks coolant for exhaust gas. Let me know how it goes or if you have more questions, thanks.

Customer: replied 8 months ago.
Did hydro chloride test and found some levels of exhaust in coolant but I also noticed that sometimes when the car gets hot the lower radiator hose is cool to the touch I know this model has two thermostats I found that out do you think it may be the second thermostat that's on the black may sometimes be malfunctioning also

There shouldn't be any exhaust in coolant, at this point your only easy option would be some top shelf stop leak. If that doesn't help then you are looking at a head gasket problem. I would replace 2nd thermostat during head gasket replacement. Let me know if you have questions, thanks.