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No Thermostat?

It will hurt your engine and your cat. Don't do it.

The thermostat is NOT there for the heater. The thermostat is there to warm up your engine asap so it runs better, runs cleaner, lasts longer, runs quieter etc.

You'll be posting questions on here in a few months asking for reasons why your 4.0 is burning oil, why the check engine light is on, why you're going thru O2 sensors, why your engine is making a tapping noise, why you get 5mpg. You get the picture.

FYI the factory set the computer to turn on the electric fan at about 220 degrees F. 4.0 liters like to run warm better.
 
blue95xj said:
Oh I was unaware they had different sizes. Might have to check that out!
Click to expand...


I was also mistaken-- it's the Pro-Line "never overheat" brand that's clearanced-- same poop/ different smell, but NOT the water wetter brand. It's still about $10.00 for a 16oz bottle.
 
OK, to throw in my .02 I have an 89 that has the following: brand new rad (CSF), 195 deg thermostat, new hoses, overflow bottle (stock style), temp sending unit, Hesco pump and am indicating 210 to 230, fluctuating back and forth, mostly under load, and a brand new fan control switch that hasn't ran the fan yet. 4.0 w/ auto trans. WTH am I doing wrong?
 
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I have sort of a similar question. I changed in a 180* thermostat in mine, and so far it's running pretty much exactly the same it was, at about 210-212 degrees. Problem or not?
 
It seems like you have absolutely no extra cooling capacity. The thermostat must be open all the time. If it gets super hot, or you get in a sand or mud situation needing extra power, you may overheat.
 
codyyy, not sure what your problem is. As far as I know, the majority of xjs run around 210-212. After a couple of years I discovered that the PO of my 93 had a 165* thermostat. Ran about 210* or so. I switched to a 195* -- runs exactly the same -- perhaps a degree or so warmer. No difference in gas mileage or anything else. I guess could make some difference if wheeled or in a very cold climate.
 
Air pockets people! Air pockets! They are a SOB to find and get rid of, but once you drain and refill your cooling system, they like to get trapped and cause overheating issues. What I have found is to fill it up with coolant and give it a few higher RPM runs to get the coolant flowing and get it nice and warm (this usually moves around the air pockets), then when it cools down a bit, GENTLY start to loosen the radiator cap and let some of the air out of the radiator, then pour more coolant in to displace the air. I have found doing this 2 or 3 times seems to get most of the air pockets out. DO NOT take the cap straight off without first letting the pressure out SLOWLY or it will explode hot coolant all over your face.

The best thing to do so this won't happen is to get an air lift. They put the cooling system in a vacuum, then you switch the valve and it sucks up coolant and fills the whole system by itself... kinda like when you evacuate an AC system.
 
sounds trippy.........haven't seen one of those.....OK, went to NAPA and bought thermal sensor tester, a little laser gun that reads temp from a distance. results of a reading on the eng at idle are:188 on thermostat housing, 195 agt temp sender, and 170 at the fan switch on the rad housing. may explain the "no fan" scenario...still considering 180 deg thermostat and an open system conversion.
 
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neanderpaul67 said:
sounds trippy.........haven't seen one of those.....OK, went to NAPA and bought thermal sensor tester, a little laser gun that reads temp from a distance. results of a reading on the eng at idle are:188 on thermostat housing, 195 agt temp sender, and 170 at the fan switch on the rad housing. may explain the "no fan" scenario...still considering 180 deg thermostat and an open system conversion.
Click to expand...

those temps are fine, why would you concider a 180 thermo when those temps are good?
 
To be honest my '98 didn't like the desert when it was in 4wd. The gauge would jump after a little while of wheeling. However putting it back in 2wd fixed the problem. I just think a Taurus fan will do the trick.
 
easy, probably easier way to purge the cooling system by fill up the system with coolant then LEAVE the radiator cap OFF then have the engine run at ~2000 RPM for such as 20 min with the cap off and yes let the truck to warm up and add when the level drops then i usually rev the engine even faster to decrease the fluid level just enough to go under where the cap will be then snap the cap in there, no problem ever again after
 
codyyy said:
To be honest my '98 didn't like the desert when it was in 4wd. The gauge would jump after a little while of wheeling. However putting it back in 2wd fixed the problem. I just think a Taurus fan will do the trick.
Click to expand...
If you don't already have a Taurus fan PM me. I have one for sale.
 
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