Alright guys new to the forum so sorry if this has ever been discussed before! I have a 2005 tax with 209k miles on it, good solid running car but a few months back had a code come up for running below operating temp (temp gauge started to fluctuate while going down mtns) so I replaced the thermostat and everything went back to normal. Until about 3 months ago.... I noticed the fans weren't coming on ( figured it's cold so radiator is cooling the coolant enough by itself) well anyways took it on a drive and it started to get a little hot so I pulled over and let it cool down and I couldn't go more than like 3 miles without stopping to let it cool. So it's been parked since and it is driving me effing crazy! Yesterday had the car up to temp after I purged the system of all possible air and felt the bottom radiator hose and it was ice cold like it had never ran..... Drove it up the road and it started getting hot. Am I looking at a clogged radiator, failing water pump, or a blown head gasket???? Also checked the new thermo in boiling water and it worked flawlessly! Please help!!!! Thanks!!

 

Suggest performing the chemical head gasket test to see if combustion gases are entering coolant.

Make sure there is no radiator blockage (debris).

You never confirmed cooling fans are coming on? If not, then turn on AC and both should engage. If not suspect fan relay, fuse, or failed motor.

Check cooling system temp w/ an IR gauge to see if system temp sensor is faulty.

good luck

 

Did you buy the thermostat from a Honda/Acura dealer? Or is it at least a genuine Honda/Acura part?

If not...there's the issue.

Never use an aftermarket thermostat.