Need help with the coolant.

I have no idea what I am doing. I changed my water pump and thermostat last night and thought all I had left to do was add my coolant. I filled up the coolant bottle and it won't take anymore. I ran the truck to 230º and nothing. What am I doing wrong?

You didn't do anything wrong (if you did everthing right ) :smart: You probably have a bunch of air in the system now.

I would park the Jeep so the front is somewhat higher than the back, and then begin the 'burping' process. Let the engine warm up as you already did, shut if off and the fluid level should go down, then add more coolant, etc....

This is the reason i switched to the 'open' system. Not nearly the PIA just to add coolant :brows: !

I bled the air through the temp sensor and got her running. :D

I'm assuming you have the Renix style ("closed") cooling system, with the pressure bottle on the firewall (passenger side)?

The system has to be "burped" to purge trapped air. Start with the engine cold, because that bottle is NOT an "overflow" catch tank, it is part of the pressurized cooling system and if you crack the cap when the system is hot, you'll be in a world of hurt.

Remove the cap, set it aside, and fill the tank to the top of the post inside (half full). Start the engine and let it warm up with the cap off. This means don't stand too close. As soon as it heats up to the point of bubbling, shut off the engine, then stand by. After about one to three minutes, as the system cools down it will begin to suck fluid out of the bottle into the system. As the level goes down, pour in more coolant, keeping the level to the half-fill line. Stop pouring when the system stops taking in coolant.

Repeat.

It'll probably take you about four cycles to purge most of the air. Be very careful when pouring in the new coolant, because the stuff in the bottle will be hot enough to scald you if it splashes. Wearing heavy rubber gloves (the kind used in labs for working with acids, not latex or nitrile exam gloves) can help a lot if you can access to them.

I've been wondering how to do this myself. Thanks for the post Eagle!

I haven't had any problems since I changed the water pump, but she ran hot @ around 230º on the way to work today. I must still have some air in the system. She's been running around 200º since I put in the new pump and thermostat.

When i burped mine i backed up on some ramps so the back end was high and started it. and loosened the temp sensor. ( on the back of the engine by the valve cover). then just let it run . i could actually see the air bubble out of it. worked fine. didnt take very long and never had to do it again.

Brandon McNulty

i tried for 2mnths to get my old system to work and finally just swapped in all new 93XJ stuff...works great and never get above 210...even in traffic

JohnQ, another simple way is to remove heater hose from t/stat housing & fill @ bottle w/ coolant, similar to previous suggestion w/ sensor removal. it would help to have frt. of mj "uphill" if possible. once you have a steady flow (w/ engine off) out of t/stat, slip hose back on, fill coolant res. to about 2/3rds full. start & allow to warm up, you can leave cap off as this method allows it to gravity bleed. then just monitor coolant temp. @ guage & as warms up, slowly remove t/stat hose to allow air out. when guage starts to move, shut off & repeat, then cap. rarely have to worry about trapped air doing it this way. easier to do then write.

mjcanoe

the easiest way is to drill a 1/8" hole at 12 and 6 o clock on the t-stat flange. So the block can fill up with water and self burp..

but you gotta know that trick before you put it together ;)

I'm assuming you have the Renix style ("closed") cooling system, with the pressure bottle on the firewall (passenger side)?

 

The system has to be "burped" to purge trapped air. Start with the engine cold, because that bottle is NOT an "overflow" catch tank, it is part of the pressurized cooling system and if you crack the cap when the system is hot, you'll be in a world of hurt.

 

Remove the cap, set it aside, and fill the tank to the top of the post inside (half full). Start the engine and let it warm up with the cap off. This means don't stand too close. As soon as it heats up to the point of bubbling, shut off the engine, then stand by. After about one to three minutes, as the system cools down it will begin to such fluid out of the bottle into the system. As the level goes down, pour in more coolant, keeping the level to the half-fill line. Stop pouring when the system stops taking in coolant.

 

Repeat.

 

It'll probably take you about four cycles to purge most of the air. Be very careful when pouring in the new coolant, because the stuff in the bottle will be hot enough to scald you if it splashes. Wearing heavy rubber gloves (the kind used in labs for working with acids, not latex or nitrile exam gloves) can help a lot if you can access to them.

Eagle,

I tried this and after I turn the truck off and it starts to cool down the coolant starts flooding back into the pressure bottle not sucking it in. It's not sucking any fluid. What is going on? What am I doing wrong? My truck has been fine but after my DW issue recently the truck started to overheat. Do I have something else wrong?

It can't flow any more into the bottle after you shut it off.

The bottle should be filled to the halfway mark with the system cold. The coolant expands when hot and pretty much fills the bottle due to compression of the air in the bottle. What may be happening is that once you shut it off, the coolant isn't circulating so it gets hotter in a couple of places and raises the overall pressure in the system, which would compress the air even more.

Once you've left it parked for awhile, does the coolant level in the bottle go back to the half-full mark? If so, there's no air trapped in the block.

Does it overheat when you're moving, or only at traffic lights? If it runs okay but heats up when you're stopped and idling, you need a new fan clutch.

I have found the temp sensor burp to be the most effective and fastest waky to do it personally. I parked mine nose down, removed the sensor for a few seconds until coolant started to squirt out, put the sensor back in and was done with it. Not disputing any other method...just saying it's easier because you don't have to run the engine to do it. ;)

I also had the issue with the bottle filling up and not sucking coolant in. My problem turned out to be the nipple for the hose on the end of the bottle (pointing to driver side) was completely clogged with something and there was no flow at all. That's when I decided to do the open system conversion.

what is the open system.

what is the open system.

What all is needed to do the conversion to an open system?

I chose to change the radiator to the later model ('91 & up), but that creates some issues with the temp switch for the electric fan that are kind of a pain to work out.

Eagle has a method that is much easier by using a metal tank with a radiator cap instead of changing the radiator.

John, are you sure your overheating. Arre you going by the gauge. I thought mine was overheating too because I was reading the gauge, which was off by thirty degrees. I bought a laser thermometer and found out everything was fine after changing a whole bunch of parts that I didn't have to. :wall:

John, are you sure your overheating. Arre you going by the gauge. I thought mine was overheating too because I was reading the gauge, which was off by thirty degrees. I bought a laser thermometer and found out everything was fine after changing a whole bunch of parts that I didn't have to. :wall:

Up until last week it has been reading around 210º. Now if I don't turn on the heater it gets in the Red Zone on the guage.

Ya, but that doesn't mean anything. Is coolant blowing out of the pressurized bottle? If it's not, measure the temp of the coolant in the bottle, the temp on the side of the block closer to the passenger side, your radiator hoses, and right where the sensor plugs in right on top of the head. It might be that your gauge is just crap. It's happened to a couple people on this board. Just eliminate the possibility that your gauge is wrong before you start freaking out like I did. If you don't have a laser thermometer use a cooking thermometer to test the temp in the plastic bottle.

Ya, but that doesn't mean anything. Is coolant blowing out of the pressurized bottle? If it's not, measure the temp of the coolant in the bottle, the temp on the side of the block closer to the passenger side, your radiator hoses, and right where the sensor plugs in right on top of the head. It might be that your gauge is just crap. It's happened to a couple people on this board. Just eliminate the possibility that your gauge is wrong before you start freaking out like I did. If you don't have a laser thermometer use a cooking thermometer to test the temp in the plastic bottle.

I'll check it when I get home.

I used a 3 row radiator in my conversion. My temp never goes over 200 and typically stays around 190 - 195 even on a the hot days that we are having right now at 90 - 95 degrees with the AC running it only got up to 200.

I think my fan clutch might be out.

Is it suppose to move by hand with hardly any effort?

I think my fan clutch might be out.

 

Is it suppose to move by hand with hardly any effort?

Mine does. So if it's not supposed to mines @#$%ed too. Did you verify the temp yet?

I think my fan clutch might be out.

 

Is it suppose to move by hand with hardly any effort?

 

Mine does. So if it's not supposed to mines @#$% too. Did you verify the temp yet?

I didn't need to verify the temp. The coolant was boiling out of the bottle by the time I got home. I picked up a new fan clutch and so far everything seems to be working. I ran normal temps on the way to work. I am going to wait until the ride home in 80º weather before I say it is fixed.