First let me wish you a Happy New Year!

I have an 87 cherokee with the 4.0 liter engine. I have read on cherokee forum where the 4.0 liter runs normally hot. And how the heater blasts you in the passenger compartment with heat.

I am thinking my thermostat must be sticking open because my water temp gauge needle is usually reading on the first line past the 100 degree mark, my gauge has a 100 degree mark then 3 lines and then a 220 degree mark in the middle of the gauge. I believe the engine is suppose to have a 185 degree thermostat, and should read higher on the gauge, I guess.

Is anyone familiar with the water temp gauges like mine on a 87 cherokee without the tach package? I am wondering what the lines should represent approx. temps? Where should the needle be pointing when running at normal operating temp?

Any ideas or suggestions on the cooling temp?

 

First the stock gauge is just a reference, it is barely a set above a Idiot light. Ne=ormal temp is about 200-210. T-stat should be 185-190. running too cold is almost as bad as running too hot. T stat is like $7 cheap insurance, even if yours is working

 

I was thinking of changing the thermostat. I heard some of the thermostats do not operate correctly, someone recommended the Stant Superstat Thermostat #45359
in 195 degree. Also to change the thermostat housing to a later model or after market one for higher flow.

Anyone know if this is good info?

 

My '91 XJ Limited was running way too cool, at the first hashmark on my temp gauge. I heard that when it runs too cool, the ECU keeps the engine in 'warm up' mode, which makes it run rich until it's up to temp (thus lowering fuel economy if it is constantly running cool). With a thermostat cycling too cool, it'll STAY in warm up mode. I replaced my thermostat with a 195 degree Stant SuperStat and it cycles at the appropriate temperature and I'm getting better MPG and the heater is actually warm. :P

This pic is of it when it was cycling too cool (for reference):

 

Today I pulled out the old thermostat and discovered it was a Stant SuperStat 160 degree thermostat.
I installed a new Stant SuperStat 195 degree thermostat and now the temp gauges is reading where I believe it should when the engine is warmed up.
Also the heater seems to be putting out more heat now.
Will see how this works out.

 

my heat is plenty warm but my gauge shows the same temp as you showed so would it still be dumping more fuel?

 

I think your fuel gauge is broken. Nobody with an XJ is ever that close to Full lol.

 

Stant SuperStat is a great thermostat.

I also like thermostats purchased directly from Jeep.

Do NOT buy cheap-charlie, no-name (ebay can carry these) stats as they are absolute junk!!

You get what you pay for with thermostats. Consider how many times that a stat will have to cycle and do its thing during its lifetime. Spend a couple of extra bucks and get a good one............