To flush or not to flush?

Dr. Internet

TJ Enthusiast
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Hi All!

I own a 2006 LJR with 36,000 miles. I bought it in early 2015. It has the six speed trans. It has never been used hard off-road or rock climbing. It goes to the beach (Padre Island) a couple of times a summer. It has never overheated and the fan and water pump seem to work fine.
It is now approaching its 17th birthday and, aside from oil, I have not replaced any fluids. My question is: should I flush the cooling system and replace the coolant? The coolant looks good and I cannot see any rust in the radiator.

Thanks for your responses!
 
Hi All!

I own a 2006 LJR with 36,000 miles. I bought it in early 2015. It has the six speed trans. It has never been used hard off-road or rock climbing. It goes to the beach (Padre Island) a couple of times a summer. It has never overheated and the fan and water pump seem to work fine.
It is now approaching its 17th birthday and, aside from oil, I have not replaced any fluids. My question is: should I flush the cooling system and replace the coolant? The coolant looks good and I cannot see any rust in the radiator.

Thanks for your responses!

I flushed mine, then the water pump started leaking. I replaced the water pump and it started overheating. Then I did a thermocure flush and the temps go back to normal. A week later my 21 year old radiator cracked at the top. What started as cheap insurance became a not very fun time. But it’s all good now, good luck with your flush😂
 
If it's brown flush it down. If it's green or yellow let it mellow.

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Thanks for your responses!
You're welcome!
 
Thanks all, for your replies. Drained the old coolant - no chunks or other particulate; no signs of rust or corrosion. Did a flush using the old Prestone kit and the garden hose. Ran for five minutes, clear water out. Removed and cleaned the coolant recovery tank. Drained that water and filled with distilled. Ran it up to temp. Drained it - all clear. Repeated. Still clear. Put in 50/50 mix of Zerex G-05.

Question - which cap? The cap that is on it is a 16 pound cap, but when I look up the Mopar part it is an 18 pound cap. I know the old cap is at least 8 yrs old and looks a little ragged, so I should replace it.

Thanks, again!
 
Thanks all, for your replies. Drained the old coolant - no chunks or other particulate; no signs of rust or corrosion. Did a flush using the old Prestone kit and the garden hose. Ran for five minutes, clear water out. Removed and cleaned the coolant recovery tank. Drained that water and filled with distilled. Ran it up to temp. Drained it - all clear. Repeated. Still clear. Put in 50/50 mix of Zerex G-05.

Question - which cap? The cap that is on it is a 16 pound cap, but when I look up the Mopar part it is an 18 pound cap. I know the old cap is at least 8 yrs old and looks a little ragged, so I should replace it.

Thanks, again!

By Prestone kit do you mean the plastic T that goes in one of the heater hoses? Several years ago I got stranded in the middle of nowhere IL on Christmas Day when my Prestone flush T decided to disintegrate and I lost all coolant.
 
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Question - which cap? The cap that is on it is a 16 pound cap, but when I look up the Mopar part it is an 18 pound cap. I know the old cap is at least 8 yrs old and looks a little ragged, so I should replace it.

This was posted in a recent thread. As you can see, the coolant boiling point increases with pressure, but 18 psi will give only around 4º increase over 16 psi. I would use 16 psi for the lower stress (pressure) on the system. In my muscle car I have run a 7 psi cap for the past 20 years with good results.

https://wranglertjforum.com/threads/have-i-cooked-my-4-0-epic-mistake-on-long-trip.67949/

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