Re-filling the cooling system after radiator replacement...

Well... What we've always done is fill it most of the way, then start it to get it circulating and top it off....

Never heard of anyone running it dry before filling it..

Kate

That makes more sense to me! :)

Clint

Clint,

Kate's right. Fill the radiator, start the engine, add your mix. Pump the upper radiator hose and wait for the thermostat to open. Once the thermostat opens, your coolant level will drop. Fill it back up and wait. Make sure the radiator opening is the highest point. If it's not, just turn the Jeep around while you're waiting for the thermostat to open. Drive it around, check it again. Don't forget the overflow container.

HTH

Carl

I only have the overflow bottle to fill through. Does that change your steps?

Clint

A little. This is an 88 to 91 XJ, correct? Basically you fill the radiator through the overflow bottle. Keep dumping coolant in untill the overflow is full. Fill the bottle, leave the cap off. Start the engine, when the level drops, fill it back up. Everything else is pretty much the same, but make sure the overflow is the high point.

HTH

Carl

Close enough. :) MJ, or Comanche pickup truck.

BTW, whoever designed the drive belt adjustment mechanism on these vehicles should have to personally apologize to every person who's ever had to adjust one. What a PITA!

Clint

Yes, it can be a PITA. However, I've found that once you get the hang of it, it's not so bad. The Ford system is much easier to adjust, but also keep in mind that your Jeep system is MUCH more reliable.

Carl

Engines with weird cooling system configurations aside, I have had very good luck taking off the heater hose that goes to the head, or the temperature sending unit, to use as an air bleeder. Also fill the heater with one hose off and the other connected to the engine. Pour in a quart or so.

Bizarre things can happen if your thermostat doesn't have a tiny bleeder hole in it. The head can get real hot, but since there is only air in it, there won't be enough heat to open the thermostat. Then you get a big bubble of steam and air which will sooner or later be released with a "burp".

This isn't a matter of seconds. More like minutes before anything starts to happen. A volunteer to watch the temperature gauge is nice, but not necessary.

Earle

I like the old chevy c-10. loosen two bolts on the alternator, stick a 2x4 between the alternator and engine, pull, tighten bolts.

You've got that right.

I used to use a pickaxe handle on my old Torino.

Ok, so it's filled, and I let it run for about 20 minutes. Got the gauge up to dead center, and it stayed there for 10 minutes. Had the interior all nice and toasty warm (right around freezing here right now). No leaks I can see underneath or at any of the hose ends. Fluid level stayed where I left it. Hood still opens, closes, and latches.

So what did I do wrong? What should I be looking for as a sign of trouble? I've got a reasonably long commute tomorrow morning (about 30 minutes at

Clint

You called that one right! Since it only takes 2 screws, I usually yank the aux electric fan out of my MJ when I have to adjust the belt. Saves more time than you would think. I also put a wobble extension on a 1/4 inch drive to turn the adjusting screw.

On filling, make sure the heater hose doesn't sit higher than the bottle. If it loops up higher than the bottle you can get a bubble in there that is almost impossible to burp out. I tie mine down to the bracket with a zip tie. I also usually pull the top hose off at the engine side and fill the radiator/lower hose thru that - I get impatient with that !@#$% bottle.

You needed a 2x4?

Earle

Get up a little early tomorrow morning and verify the fluid level. Otherwise, you should be good to go.

Earle

(over-heating,

Yep. There ain't nothin you can't fix on a chevy C-10 with a 2x4. :)

The 2x4 was just the right size to wedge in there. Worked well on motor mounts too.

On the closed cooling system in you truck it must be burped. As explained air is trapped around the thermostat and it does not open, hole or no hole! Air rises and that's the highest point. Been there, done that! I changed the antifreeze on a 89 I had once and it got very hot very fast. Keep a good eye on the temperature. What I did was loosen the upper radiator hose clamp BEFORE it got red hot and let the air out.

Jo Bo

I just burp mine by squeezing the upper radiator hose till air bubbles come out the fill. Then add more antifreeaze as I release the hose... wash, rinse, repeat till it just won't take any more.

I just took it out for a 30 minute drive; everything seems ok. Temp never made it more than half-way up the gauge, and I was watching it like a hawk. :)

Cl>> On the closed cooling system in you truck it must be burped. As