Overheating Problem again.. what now?
 

I got an over heating problem with my 2003 Discovery. It did this about 2 months ago and i suspected thermostat so i changed it out and its doing the same thing again. it s over heating, both fans spinning, no coolant loss but when the lower part of the house coming out of the rad into the thermostat is cold the hoses coming out of the top of the thermostat are super hot and hard. thermostat stuck again?

After you changed the thermostat 2 months ago did it stop the overheating problem?

What thermostat did you use? Motorad or Genuine LR (grey 180)

Are you overheating while driving or just when idle?

Have you tried to bleed the air out of the system again?

yes after changeout it went away. its a white one but got it from advance autoparts its a CALORSTAT brand. it will overheat either idle or driving. it sure seems the thermnostat is blocked cause why would the outlet side be super how and inlet so cool if it was open? it be more uniform temp. what is the best way to bleed it?. i'm going to pull it apart and place the thermostat in hot water make sure it opens.

also could you tell me the proper bleed procedure. i came up with another idea to possible eliminate the thermostat. i kept the old one and if i hollow it out and get ride of the thermostat and hook it back up run it and it didn't overheat i'd know that it the thermostat (new one ) is bad.

Which Calorstat did you get? It should be marked. I had one for a few weeks and it ran much hotter than I like, up to 220°! Upon inspection I found it was rated at 98° C!

The proper bleed procedure is as follows... done with the engine stone cold and not running... unseat the overflow tank and raise it above everything else in the system, as high as the fragile hoses will allow... hang it from the hood with a bungie or something similar. with the top off the cooling tank and your premix at the ready, open the bleed screw at the T, allow coolant to flow out until you get a steady stream, topping the overflow tank if it gets low. Reinsert the bleed screw when it appears all air bubbles are out. replace overflow tank and start engine, run heater, if you have no overheating, then you are done. If it still overheats, repeat this procedure next time the engine is cold. Do not open the system with the engine running or still under pressure.

Sometimes it takes a few cycles of bleeding to get it right.

well i have no idea what the degree is. doen't say on advance autoparts. they say 188-197. i'm going to take it out and test it. could the rad be blocked?

Dave gave you the correct bleed procedure above, follow it and you should be good. As for the thermostat, I would ditch the after market and spend the $80 on the Genuine Grey 180. Just my opinion.

The most likely case is that you did not bleed properly.

Second most likely is a failed stat. Calorstat and Motorad have known quality control issues.

Get an OEM 180° stat from one of the usual vendors.

for all the help. its funny if it wasn't b leed right it would run 2 months with no issues and then just start out of the blue.thanks how is atlantic - british on there parts?

follow up on the senario: my daughter came out of work started up and about a mile down the road the temp dial was in the blue (cold) but the red dot came on (temp warning?) then it settled in the middle then started to rise. she pulled over called me. now we live 2-1/2 miles away and it was 25 degrees out last night by the time i got there it was back to normal. i started up and by the time i dove the last mile it was hot again. no bubbling no leaking. thats when i noticed the difference on the hoses temps

Yes, you could have other issues, but bleed it correctly... then see if it still overheats, and if so follow the standard procedures for identifying your cooling system issue.