Burping the raditor...

i just installed one about a week ago and im have a tough time burping it... it will stay at 180(i have a 180 t stat) and then slowly climb to 210 and yesterday went almost to the notch after 210, and it boils over after i shut it down, any proper way to burp the system??

Year/engine, open/closed system?

If a 4.0 closed system some recommend parking nose down and removing the temerature gauge/light sender located driver's side rear corner of the head. Some recommend pulling the upper radiator hose and pouring coolant in there. Also, if a closed system, does that wrong thermostat you have in there have a hole positioned at 12 o'clock in relation to the engine--it helps.

You have made a decision to use a 180 vs. 195 degree thermostat, which is going to screw up all the sensors, make the engine run way to rich, and if a DD you will fail smog test. If you were overheating there a alot of other things to do before using the wrong thermostat.

Was it good before you changed the radiator, or did it have the same problems? As joe said, 180 tstat is not a good idea. Excessively rich mixture wears engines out in many ways.

well its a 2000 xj, i changed it cuz it had nine years on the clock and figured a new one was in order! and yes it did do that before i changed it, but it wont not go past 210.... and i smogged my jeep bout 6 months ago and passed with flying colors.... and i have been runnin the 180 for bout 1 1/2 years so far no problems so far besides this after the radiator change....and the way im burging the system is taking the cap off the rad., and running it and filling it up until its full....

Ok, you have the open system and it really is self-burping, unlike the closed system.

To try and speed up the process you can park your vehicle on a steep incline, angled so that the radiator cap is at the highest point. If the engine is hot you will have to wait awhile before removing the cap. Once the cap is off start the engine and add coolant as needed until it is full. Remember that if there is an air bubble in there it could push coolant out so be careful, Ok?

If the system just keeps boiling out coolant that means the engine, a really magnificent pump, is adding air to the cooling system, and that isn't good.

ok thanks joe!!! ill do that and u do recommend that i go back to a 195?! i know there is a huge debate over this!

blackdoutxj said:

ok thanks joe!!! ill do that and u do recommend that i go back to a 195?! i know there is a huge debate over this!

Click to expand...

Yes, I recommend the 195. If you are running too warm with a 195 your system has problems that are going to bite you later on.

XJ cooling systems are marginal, at best. I have been to your part of the country, so you are starting at a disadvantage. Keeping the system clean, proper coolant and cap, is absolutely step one, and the cheapest.

The most effective improvement would be to upgrade the fan clutch. The fan clutch is one of the most neglected parts of the cooling system. Most old timers (thats me!) will tell you to replace the water pump and fan clutch together. You can use the ZJ HD fan clutch NAPA 272310 for $44 for a low-buck upgrade. It will be noisy--not as noisy as a fixed blade or flex blade fan, but you will hear it. It is more noisy because it moves more air--the HD spins at 80 to 90 percent of the shaft speed versus 60 to 70 percent for the standard. When disengaged both will turn at 20-30 percent. Both engage when the temperatur of the air flow through the radiator hits 170 degrees, and that is about 30 degrees less than the coolant temperature.

You can buy a "high flow" thermostat, Mr. Gasket makes them, and you can buy or make your own "high flow" thermostat housing. You can buy a "high flow" water pump. You can buy a two or three core radiator. You can add an efan with a command switch on the dash for extra cooling when needed, or upgrade an existing efan with a command switch.

Good Luck.

There's not really any debate over the thermostat. Engines are more efficient at higher temps - the engineers spec'd a 195, and set the fuel injection map to recognize 180 as still in the warm up range, and run rich as a "choke" setting until it gets to optimum. Then the system goes to closed loop, starts paying attention to the O2 sensor, and works as designed.

The 180 temp guys are just forcing the system to run rich and dirty all the time - even when commuting to work when they can't really use the insignificant increase in power.

As joe said park on incline and fill first.

Be sure the small hose connecting over to the expansion tank is good. and the coolant is at the "Full" mark on the expansion tank.

From here on DO NOT OPEN RADIATOR CAP! IF opened start over!
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Warm up engine 5 minutes or so- Shut down and cool down 2-3 hours -ADD coolant as needed to keep between "Full-Add" marks on expansion tank.

Repeat until level holds between full-add marks cold and hot. (normally varies 1/2-1 inch)
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Keep close watch on level for a few days.

Please note that the radiator cap is above the expansion tank physically. The system works by the hot expanding coolant pushing air out thru the expansion tank and pulling coolant back in as it cools back down. If the radiator cap is opened it lets air IN!.

This is in a good system-if bad head gasket, loose hoses, etc.....

Good Luck

My 2000 XJ worked fine just slowly filling up the radiator when it was cold. As you fill it, some air bubbles out and you can put a little more in. When no more air bubble out, even after 15 seconds, you stop adding. Now you have coolant up to the bottom of the radiator cap. Put the cap on. Top off your overflow bottle to the cold mark. Start it and let it get hot. Stop it and let it cool down. As long as you don't run out of coolant in your tank, you are good to go. Don't keep taking off the cap to check. Be carefull not to break the plastic neck on the radiator where the cap sits.