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2006 3.7L 4x4 Jeep Commander
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Discussion Starter · #1 ·
I found the following directions for the refill the cooling system on a 2006 Jeep Commander 3.7,
REFILLING COOLING SYSTEM




"3.7L



1. Tighten the radiator draincock and the cylinder block drain plug(s) (if removed).
CAUTION: Failure to purge air from the cooling system can result in an overheating condition and severe engine damage.
2. Fill cooling system with the antifreeze mixture (Refer to LUBRICATION & MAINTENANCE/FLUID TYPES - DESCRIPTION). Fill pressure bottle to service line and install cap.
NOTE: The engine cooling system will push any remaining air into the coolant bottle within about an hour of normal driving. As a result, a drop in coolant level in the pressure bottle may occur. If the engine cooling system overheats and pushes coolant into the overflow side of the coolant bottle, this coolant will be sucked back into the cooling system ONLY IF THE PRESSURE CAP IS LEFT ON THE BOTTLE. Removing the pressure cap breaks the vacuum path between the two bottle sections and the coolant will not return to cooling system.
3. With heater control unit in the HEAT position, operate engine with pressure bottle cap in place.
4. Add coolant to pressure bottle as necessary. Only add coolant to the pressure bottle when the engine is cold. Coolant level in a warm engine will be higher due to thermal expansion."

My issue is the language, this may sound silly but i want clarification, "fill pressure bottle" refers to the reservoir, "cooling system" refers to the radiator; am I reading this correctly?
The instruction for the 4.7 are extremely clear compared to the 3.7.
Sorry for my ignorance but just want to be sure before I start working on it.
 

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2006 Commander Limited, 5.7 Hemi QD2
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2,372 Posts
The pressure bottle is the over flow reservoir - yes. "Cooling system is not only the radiator but the entire engine and hoses, heater etc.
 

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2006 3.7L 4x4 Jeep Commander
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11 Posts
Discussion Starter · #3 ·
Now I understand. My other question is once the cooling system and reservoir are full, do I have to use the bleeder valve to let the rest of the air out? or the system will do that as the engine is running.

Thank you so much for your help.
 

· Super Moderator
2006 Commander Limited, 5.7 Hemi QD2
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2,372 Posts
The running should be enough but when you start it up right after filling and it is cold, leave the radiator cap off and if the level in the radiator goes down - top it off. As it gets warmer tighten the cap before it gets hot. But yes running it the air and excess coolant will go int the overflow bottle or back into the radiator as needed automatically.
 
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· Registered
2006 Commander Limited 4.7 130,000 miles
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The running should be enough but when you start it up right after filling and it is cold, leave the radiator cap off and if the level in the radiator goes down - top it off. As it gets warmer tighten the cap before it gets hot. But yes running it the air and excess coolant will go int the overflow bottle or back into the radiator as needed automatically.
Another thing to note that I did not think of when making sure all air was clear in the cooling system is that if you have rear heat to remember to turn that to the heater on position, to make sure coolant is flowing throughout the system.
 
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