How to flush coolant for stock 1990 Cherokee (closed radiator system)?
CF Veteran
Joined: Jun 2011
Posts: 2,858
Likes: 1
From: Nor-Cal
Year: 1990
Model: Cherokee
Engine: The venerable 4.0
Originally Posted by skunker
Hey guys, gonna splice that hose in a bit. Any special tool needed? Basically just cut it and put that Tee in there?
Thread Starter
Junior Member
Joined: Oct 2009
Posts: 43
Likes: 0
From: San Antonio, TX
Year: 1990
Model: Cherokee
Almost there! Need a bit more help...
So, I got the "Tee" installed on that hose and according to the Prestone Flusgh kit instructions, since I don't have a radiator cap, I need to disconnect the upper radiator hose at the radiator, put the "splash tube" into the radiator neck and open radiator drain.
Confused about the radiator drain.
I think I see it...it looks like a petcock and its at the bottom passanger side of the radiator. DO I need to remove that? It's a pain to stick my arm/hand in there and try to loosen it.
1.) So, just wanted to double check.....do I remove the upper radiator hose AND the radiator drain petcock?
2.) I don't need to touch the lower radiator hose, right?
THanks! Almost there (as you can tell, I"m not mechanically inclined
The prestone flush kit instructions I'm using are here: http://www.prestone.com/products/print/461?popup=1
So, I got the "Tee" installed on that hose and according to the Prestone Flusgh kit instructions, since I don't have a radiator cap, I need to disconnect the upper radiator hose at the radiator, put the "splash tube" into the radiator neck and open radiator drain.
Confused about the radiator drain.
I think I see it...it looks like a petcock and its at the bottom passanger side of the radiator. DO I need to remove that? It's a pain to stick my arm/hand in there and try to loosen it.
1.) So, just wanted to double check.....do I remove the upper radiator hose AND the radiator drain petcock?
2.) I don't need to touch the lower radiator hose, right?
THanks! Almost there (as you can tell, I"m not mechanically inclined

The prestone flush kit instructions I'm using are here: http://www.prestone.com/products/print/461?popup=1
Thread Starter
Junior Member
Joined: Oct 2009
Posts: 43
Likes: 0
From: San Antonio, TX
Year: 1990
Model: Cherokee
Ok! Put the radiator hose back on. Now, I had to take the grill off in order to get to the radiator drain petcock. But, the petcock is a pain to get loose. Just to make sure I'm twisting it the right way....lets say you are standing in front of the passanger side front wheel....which way do you turn the petcock to get it loose? I'm afraid of breaking it....already sprayed a bit of wd40 on it...
Last edited by skunker; Sep 11, 2011 at 02:26 PM.
CF Veteran
Joined: Jun 2011
Posts: 2,858
Likes: 1
From: Nor-Cal
Year: 1990
Model: Cherokee
Engine: The venerable 4.0
Ccw it screws out. They can be a pain. I ended up draining the block and flushing there and through the top hose into the radiator with the bottom off and separately through the heater core once
Thread Starter
Junior Member
Joined: Oct 2009
Posts: 43
Likes: 0
From: San Antonio, TX
Year: 1990
Model: Cherokee
Might have to go and disconnect the lower radiator hose instead if this doesn't get loose anytime soon. I am afraid of breaking the petcock AND having a new source of coolant leaks in the future.
Thread Starter
Junior Member
Joined: Oct 2009
Posts: 43
Likes: 0
From: San Antonio, TX
Year: 1990
Model: Cherokee
I was able to easily get the drain plug off by simply hitting it with a wooden mallet and a screwdriver. Easily twisted off after that. So, I then started to flush and i had water spurting out of the hose connecting to the reservoir bottle...and the seal from the Tee to the garden hose was not tight (had to apply plumber's tape) before making a mess...but i let it run for 2 minutes and the water was clear by that time. I could have let it run longer, but I was afraid of getting cited for a ticket since we're under a severe drought here in Texas...and if they catch your water running off into the gutter, you will get a ticket. Damn water *****.
Anyways, nothing major in the bucket except for a little bit or rust deposits I assume...but hard to see. A slight white film to the water but I guess that's from the cleaner solution. All in all, my first flush and I want to thank you guys for leading me to the way.
All i have to do now is burp the air out. Im' going to disconnect the coolant temp sender unit....I am going to do that with the engine off and then pouring antifreeze into the reservoir, correct?
Anyways, nothing major in the bucket except for a little bit or rust deposits I assume...but hard to see. A slight white film to the water but I guess that's from the cleaner solution. All in all, my first flush and I want to thank you guys for leading me to the way.
All i have to do now is burp the air out. Im' going to disconnect the coolant temp sender unit....I am going to do that with the engine off and then pouring antifreeze into the reservoir, correct?
Thread Starter
Junior Member
Joined: Oct 2009
Posts: 43
Likes: 0
From: San Antonio, TX
Year: 1990
Model: Cherokee
Alright, "burped" the system and put everything back together. It does seem to be running hot again this time around....the coolant gauge seems to be creeping up more and more (already past 210...more like in the tick mark after 210...almost to red). There must be a weak link somewhere or I didn't burp it correctly. Could the flush kit "tee" be the culprit? I left it on there. Dang it...will drive it some more tomorrow and find out if it's a fluke or not.
Last edited by skunker; Sep 11, 2011 at 07:55 PM.
CF Veteran
Joined: Jun 2011
Posts: 2,858
Likes: 1
From: Nor-Cal
Year: 1990
Model: Cherokee
Engine: The venerable 4.0
Originally Posted by skunker
Alright, "burped" the system and put everything back together. It does seem to be running hot again this time around....the coolant gauge seems to be creeping up more and more (already past 210...more like in the tick mark after 210...almost to red). There must be a weak link somewhere or I didn't burp it correctly. Could the flush kit "tee" be the culprit? I left it on there. Dang it...will drive it some more tomorrow and find out if it's a fluke or not.
Thread
Thread Starter
Forum
Replies
Last Post
Brill
Stock Grand Cherokee Tech. All ZJ/WJ/WK Non-modified/stock questions go here!
27
Feb 6, 2020 12:41 AM
Tompop
Stock Grand Cherokee Tech. All ZJ/WJ/WK Non-modified/stock questions go here!
16
Aug 25, 2015 03:35 PM
Trail-Trekker
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
0
Aug 20, 2015 06:26 PM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)



