i cant figure it out!!

i have an 87 with whatever cooling system has the overflow bottle..anyways, i cant get the running temp to where it should be, it started out running at about 120, and now its at about 140 give or take. ive replaced the thermostat, water pump, and the stupid lil bottle that always cracks, flushed the radiator, and have burped the system to no end. but know matter what i do i cant get the temp up. i dont think its a bad sensor cuz i dont have very much heat coming out either...its about luke warm, and when the temp gauge rose about 20 degrees the temp got slightly warmer. anyone have any other ideas??

thanks in advance,
jmeti000

Pull the thermostat drop it in a pan of water..heat it up and see what temp it opens at to rule that out. It does sound like you've got a sending unit issue to me though.

What exactly caused your temps to drop? Was it like that since you bought it? Did you change anything, after which temps stayed low? Can you get the XJ to warm up by just letting it idle for a while?

To check sensors you can get/rent/borrow a temp gun to check the actual temps. To see if the t-stat got stuck open, just warm the XJ up (to whatever you get it driving) and then let it idle for a while. If it's the t-stat eventually the temps will come up when idling.

To me it sounds a lot like a bad t-stat. I've had similar problems and changed through 3 aftermarket t-stats (including hi-performance) until I got a dealer t-stat, which finally got it right.

Good luck.