Brown coolant
CF Veteran
Joined: Nov 2008
Posts: 7,874
Likes: 100
From: Northern Ontario, Canada
Year: 1990, 1999, 2000
Model: Cherokee
Engine: 4.0
at some point in it's life, someone probably ran straight water.
your rad may be filled with rust at the bottom tho.
as long as it's not overheating, you should be ok.
i bought a jeep like that, only was worse. flushed the heater core and replaced the rad. filled with new coolant, colour came back a bit, but not near as bad as before.
i think you will be fine as for the colour of the coolant, maybe do another drain and fill or flush before you go and fill with new 50/50 coolant.
your rad may be filled with rust at the bottom tho.
as long as it's not overheating, you should be ok.
i bought a jeep like that, only was worse. flushed the heater core and replaced the rad. filled with new coolant, colour came back a bit, but not near as bad as before.
i think you will be fine as for the colour of the coolant, maybe do another drain and fill or flush before you go and fill with new 50/50 coolant.
CF Veteran
Joined: Aug 2011
Posts: 10,489
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From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
The rad drain can be a joke, pulling the lower hose lets you flush allot better. Someone mentioned pulling their t-stat housing and running a hose in there with the lower hose off. I haven't done that myself. I suppose if the water pump were off a guy could flush from there as well.
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
The water pump will not prevent a good flush of the head and block.....don't need to remove the t-stat cover either. Remove the heater hose and rad hose from the stat cover and remove the bottom rad hose from the water pump. Stick a garden hose in the heater hose and flush. Then stick the garden hose on/in the heater hose nipple on the stat cover and flush. Then stick the garden hose in the the top rad hose and flush. Do the 3 flushes in that order.
A superior head/block flush can be done when both the stat cover and water pump r removed. Stick a garden hose in the stat hole in the head and flush out at the base of the block.
A superior head/block flush can be done when both the stat cover and water pump r removed. Stick a garden hose in the stat hole in the head and flush out at the base of the block.
Last edited by djb383; Jan 13, 2015 at 05:12 PM.
Thread Starter
Junior Member
Joined: Mar 2014
Posts: 67
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From: Anchorage Alaska
Year: 1999
Model: Cherokee
Engine: 4.0
Another question , I do not have my ac system hooked up. I don't have a condenser can this "open" system cause air to get into the cooling system and cause rust? If so, is there a way to close it up as is?
Thread Starter
Junior Member
Joined: Mar 2014
Posts: 67
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From: Anchorage Alaska
Year: 1999
Model: Cherokee
Engine: 4.0
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
......and when the motor is COLD, remove the rad cap frequently to check the color/level. When the color starts changing from bright green, flush and re-fill with fresh.
Banned
Joined: Feb 2014
Posts: 2,379
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From: Florida
Year: 2000
Model: Cherokee(XJ)
Engine: Golen 4.6L
I could be wrong, but I don't think that's rust.
When water boils out of coolant, the extra concentration left behind will precipitate out of the solution and become a reddish mud. That mud is sticky and abrasive and can wreck a water pump in a fairly short amount of time. It will fill up the water jackets and can be impossible to completely clear without some disassembly.
As I said, it's caused when the coolant boils, but you don't have to completely overheat your system for that to happen. If you have a cracked head or leaking head gasket that is allowing hot exhaust gas into the cooling system, the gas hitting the coolant can boil it right there at that location and start this process. You might see a jump in temperature if that happens, without actually overheating. You can have this sort of head leak without having coolant in your oil.
If I were you, I would test the system for the presence of exhaust gases in the coolant. Many shops will have a combustion leak tester, or you can buy your own for $50 to $60. If it tests positive, you know you either have a head crack or a leaking head gasket. Then you can move on to figuring out the exact issue.
Also, if you're smelling coolant, the cooling system itself may be leaking somewhere. Have you climbed under the front of the Jeep to see if your water pump is leaking from the weep hole? If it is, that brown crap will be running down your lower radiator hose from the engine. You need to look at it from underneath to see it.
When water boils out of coolant, the extra concentration left behind will precipitate out of the solution and become a reddish mud. That mud is sticky and abrasive and can wreck a water pump in a fairly short amount of time. It will fill up the water jackets and can be impossible to completely clear without some disassembly.
As I said, it's caused when the coolant boils, but you don't have to completely overheat your system for that to happen. If you have a cracked head or leaking head gasket that is allowing hot exhaust gas into the cooling system, the gas hitting the coolant can boil it right there at that location and start this process. You might see a jump in temperature if that happens, without actually overheating. You can have this sort of head leak without having coolant in your oil.
If I were you, I would test the system for the presence of exhaust gases in the coolant. Many shops will have a combustion leak tester, or you can buy your own for $50 to $60. If it tests positive, you know you either have a head crack or a leaking head gasket. Then you can move on to figuring out the exact issue.
Also, if you're smelling coolant, the cooling system itself may be leaking somewhere. Have you climbed under the front of the Jeep to see if your water pump is leaking from the weep hole? If it is, that brown crap will be running down your lower radiator hose from the engine. You need to look at it from underneath to see it.
Last edited by extrashaky; Jan 15, 2015 at 01:24 AM.
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From: Saginaw Mi area
Year: 1994
Model: Cherokee
Engine: 4.0
Banned
Joined: Feb 2014
Posts: 2,379
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From: Florida
Year: 2000
Model: Cherokee(XJ)
Engine: Golen 4.6L
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
Senior Member
Joined: Nov 2013
Posts: 773
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From: Lapeer, Murder Mitten
Year: 2000
Model: Cherokee
Engine: 4.0 I6
Pressure test cooling system. Test for ex gasses. Before flushing.
Flush system multiple times until clear. Consider 2 part cooling system cleaner. Be sure to back flush heater core.
Flush system multiple times until clear. Consider 2 part cooling system cleaner. Be sure to back flush heater core.




