Closed Cooling System Maintenance

I own a 90 xj and with winter here I'm thinking more about my cooling system. About 3 years ago I replaced my radiator with an all metal 3 row radiator from CFS and when I did that i replaced my hoses and later on in the year, replaced the overflow bottle with one from Crown. I'm not looking to replace a water pump unless it needs to be, but I was thinking about changing the t-stat and draining/flushing my cooling system. The coolant has started to turn a bad brown color, what is the best way to flush my system completely and get it clean? Would it be a good idea to change to a newer t-stat housing with the bung so i can add another sensor in later, or is it possible to work in some sort of valve there to purge the engine of air? I still cannot get the air out of my system now from when I did the rad change 3 years ago.
Thanks for the help!
Joe

Install a metal t- or rad cap t in either the rad hose or the hose that goes back to the HC, if you care to do that. Burping the system is really easy when you have the cap off the tank. The drain XXXX is on the pass side of the rad, best way is to remove your headlight bezel so you can get to it, I also recommend putting a small hose on it to drain into a container. A stock temp t-stat replacement is fine. If you want a newer t-stat housing , go for it. To flush rad, remove hose @ t-stat housing and run water thru it with the drain XXXX open.

This is what I did with mine.



It's a housing out of a '92...from the salvage yard...$2.00. The bung is already there and I stuck a pet@ock in there to bleed off the air.

But then I converted to an open system.

If you want to flush almost ALL the coolant out, take the lower rad hose off and take out the drain plug on the drivers side block (under the manifold). Then remove the t-stat and shove a hose in there. Flush away. If you want you can put it back together (lower hose and drain plug) fill it up with water and do it again.

I might have some rad flush crap from when I worked at ford in slo, if you want, joe.

First, put a commercial flush in there and follow the directions.

Replace the thermostat with a 195 degree Stant Premium. I did the same to mine as ParadiseXJ--quickest "burp" in town. Drill two small holes in the flange opposite of each other. Drill them far enough in from the outer rim of the flange so that they will not be covered by the housing or gasket. The holes simplify getting the air out of the system. If you do not use an updated housing with a petcock in it, you will have to park the XJ with a nose-down attitude. Then remove the temperature gauge/idiot light sender from the rear of the head and pour coolant into the pressure bottle until you get no more air from the port where you pulled the sender, then replace the sender.

joe_peters said:

petcock

Click to expand...

How'd this get by?? Everytime I write petcock it gets censored??

:doh:

Well I guess it went through this time...or did it?

ParadiseXJ said:

How'd this get by?? Everytime I write petcock it gets censored??

:doh:

Well I guess it went through this time...or did it?

Click to expand...

When censored, were you typing pet XXXX? As in your favorite rooster?

I was using petcock as a noun. Maybe, based on some of your other posts, they censors thought you meant it a verb!

You are a humerous man joe. I guess it could be a verb AND a noun. A phrase even!!

I'll stop right there...