cooling fan question

I have a 1990 Renix XJ. I have removed the AC system and had to bypass the heatercore. My rig been running at 210 (added gauge cluster at same time.. only had idiot light before) after i did all of this and i can see the tstat opening up and keeping it around the 210 mark so i am guessing that is what it is set for being that i only had the idiot light before . Well when i am driving this thing and for most part idling it stays at 210. Randomly the other night I noticed my gauge getting close to red.. but then quickly went back to 210 when I got to driving.. so if figured its a gauge thing. Today it did this again and let it idle for awhile after i got home... it climbed again toward the red. So I also noticed a lot of coolant in the coolant bottle and so i opened the cap off it to see if it would let out pressure if there was an air bubble. It erupted out and then went back down. I have been reading some stuff about air bubbles on this and going to try some of that stuff, however I feel part of this is due to the cooling fan not coming on. I am not even sure what temp it should come on at? I do know that when it climbed into the red today that it should have been on and was not...

I am thinking that this thing is overheating at idle since the cooling fan is not coming on. At work another XJ guy and I tested the fan it works. I am guessing that maybe somehow i cut off the fan when i took out the ac system and unplugged the compressor? If that is a possibliity how could i bypass this thing so it will come on and off or just keep it so the fan is on all the time? I left the compressor in as a pully for now and maybe a future onboard air conversion.

i put mine on a switch inside so i can control. i did the same as you with the AC and it would never kick on. if you wanted it to turn on when the car is on yo could wire a relay into an ACC power source so the fan would turn off when the key is off

It (should) comes on around 220-ish, and/or when the AC system is activated. You would probably need to look at wiring diagrams and trace wires and make sure things are connected properly. You can also run a bypass/override switch with a relay. Maybe get one of those temp switch kit with the override switch, if you can't get it going with the stock wiring.
The switch is nice too, so you can turn off the fan if you go underwater.

1. A**uming it wasn't 115 degrees in the shade your cooling system, less the efan, should be handling things fine.

2. Air bubbles in the closed cooling system will play havoc, so it is CRITICAL that the system be "burped". Do a search, lots of threads on the hows and whys of burping.

3. If the radiator is reasonably clear, the coolant a proper 50/50 mix, the system is holding pressure, then the mechanical fan's clutch should provide all the cooling you need. When the temperature of the air that flows through the radiator and hits the bi-metal spring on the front of the fan clutch it will engage. At that time the coolant temperature is approximately 30 degrees higher, or about 200 degrees, so there is no way you should be hitting the red zone.

Things to do:

Check the condition of the fan clutch.

Burp the system.

New pressure cap--Stant number 10244, Volvo 2.3 L cap; its an upgrade that fits tighter on the pressure bottle, has a lower profile so it doesn't hit the hood, and holds a slightly higher system pressure which raises the coolant boiling point, sort of a win/win/win upgrade.

SAFETY NOTE: removing the cap from a closed system pressure bottle, when hot, is the same as opening the radiator cap on an open system when hot--a good way to get seriously hurt.

I added the cooling fan and all the wiring to my '90 this past weekend. It was a non A/C truck so I had to start at the fusible link and work my way forward. If you want the simple way to keep the fan on all the time jump the thermal switch connector on the radiator.
The way the A/C controls the fan is that it sends power to the diode when you turn the A/C on. When you removed the A/C you probably disconnected that wire. You can add a toggle switch to that wire (should be orange/blk tracer) that would send ignition on power to it. Then you'd be able to manually control the fan as well.