good idea... especially while rocking the apartment life without a garage and a way to just do continuous flush until as clear as you can get it.

 

I don't even wait that long. Every other year in an even year it gets swapped out.
And there is at best only 6K on the anti-freeze.
The $10 it costs me to do that every other year is well worth it IMO.
Plus since I drop the lower hose I only get 2 out of the 3 gallons out when I do.
Another reason why I do it more often.

 

That's true...and it's the easiest way to do it...b/c whoever designed the petcock location and function on our XJ's definitely should NOT have shown up to work on the day of the design process.
I've done countless coolant changes on vehicles in my life and the XJ is a royal PITA....from underneath or even taking the headlight ring out.

 

Not sure of this helps or just appears to help. Park it facing down hill, drop the lower hose from the block and that seems to drain the back of the block better. You can even turn around and let the radiator drain, just don't run the engine too long without coolant.

 

I thought about tapping the ignition to push out more anti-freeze and even tranny fluid, cause I also swap that out every other year in an even year (about 4 quarts there), but figure why bother cause I do it so frequently.
Maybe this year for the anti-freeze I will put the ramps under the rear and see what happens.
My landlord uses my old anti-freeze, it is always still really green and looks really clean when I give it to him, and have a garage that takes my old oil for that waste oil furnace.

 

On the manifold side of the block, there are 2 plugs in the water jacket. They are between cylinders 2 and 3, and between cylinders 4 and 5. I think they are something stupid like 7/16" square socket plugs. I'd put brass pipe plugs back in if you pull them. They will let you flush all the debris out of the block itself. If there is a lot of rust behind them you can probe the holes with a screwdriver to clean them out. The rear one is tough to get to because of the exhaust.

Filling it is easy if you take out the temp sensor and fill until coolant flow out, then re-install it and finish filling. That removes all the air trapped in the block and head.

 

That would certainly assist a little bit on that end... but then afterwards and topping up the coolant... flip the jeep around so that it's facing up-hill slightly... that way when you have the cap off it's easier to get all the air out of the system.

 

Another tip is don't touch that stupid petcock. They seem to be made to sell more radiators.

Just drain it from the lower hose. If you have the driver's side front as the low point on a slope, everything should come out.

 

Radiator lesson I learned. 99 Cherokee I6
A few years ago I had a leaking radiator. After looking at the options I go the idea that it would be a good idea to go with a 3 row aluminum radiator with 3 high flow electric fans.
It was a lot of work getting all of this in the Jeep.

First drive I was over heating. I checked and double checked everything. Finally got it to cool down but when trail riding I would over heat.

I took it to a mechanic friend and he asked why I had replaced the OE radiator. I told him of my research and that this should be better. His comment made a lot of sense to me.
”Jeep spent millions of dollars engineering the Jeep and all the parts to work together”.

Long story short, I ended up purchasing an OE radiator and put that and the original fans back in. Going to the desert and rock crawling in Moab and I have not overheated since.

 

yeah... I remember back in the day that they used to be right on the bottom, easy to get to as well.

 

Got a new radiator, new hoses, new thermostat housing installed. Left out the new thermostat for the moment as I'm using the following video as a basis for trying to flush out the system:


Basically, leave the thermostat out temporarily to increase circulation, then run water through a number of times, then install thermostat, fresh coolant, and continue on your merry way...…

Trouble is, I've probably run fresh water through a half dozen times already, and it never comes out anything but a lovely shade of rusty brown. Runs great, just always comes out brown even after putting clean water in.

Just keep going?

 

That cooling system looks pretty standard - or at least, much like mine did. I didn't have all that buildup in the Tstat but as said above, that's probably a stop leak product.
I flushed mine through with a hosepipe, refilled with water and flush agent stuff. Drove for a week, did the same thing the next weekend, flushed and put in proper coolant.
It's better now and the coolant stays almost green, but you never fully get rid of all that orange stain from the pipes.

 

Did you try using a hose to flush the radiator, engine, and heater core? That does wonders.

 

Success!!!! Well, I hope...… To answer your question, yes.....

Ran down to my local big box hardware store and got the right pieces to adapt a garden hose to my old lower radiator line. This is what they ended up looking like:



Ran that into the bottom of the engine, and just rotated the top radiator hose to extend out past the hood:





As you can see, the water was still coming out pretty brown. I didn't manage to get an image when I first started, but the image below is about 5 minute after I first started, and the second one was about 10 min after that:





Keep in mind, the top image is about 5 min after I started running water through it, and after I had already flushed the whole system about 8 times, with a Prestone coolant system flush in it twice. I did run it a few times when hooked up to the hose. You could definitely feel the outlet temp warm up when it was running. The temp gauge hardly moved though.

After that I did the same thing to the radiator (the new one just installed), garden hose into the bottom, back flowing it out the top, until that ran clear. Then did the same thing to the heater core:



Even after having flushed the whole system, the heater core still came out pretty dark. I'm pretty sure I was back flushing it (someone correct me if I'm not), and even after it ran clear for a bit it would still turn brown for a second or two. My guess being crud in another channel in the core would just let go and exit the system. After I did that I ran it through the other wayt for good measure.

Then I put it all back together. Still yet to do: install the new thermostat and gasket, and finally top it off with fresh coolant. Unfortunately I start a work trip tomorrow so that's a project for later next week.

So did I accomplish anything worthwhile? No idea.... all things being equal I'd rather have no rust and crud than the alternative, so maybe. IMHO, totally worth a trip to the hardware store just to get it done right.

 

Did you just dump all your old coolant onto the parking lot?