[AaronHulst]

I have an 01 Hyundai elantra. The temperature gage reads cold unless im at speed on the highway, then it sits just below the half way point. Fluid levels are good. There is pressure in both upper & lower hoses, nut the lower remains cold. Replacing the thermostat & the problem persists. What could be causing this? Any help would be much appreciated.

 

[flemmons]

Is the heater working? If the heater is working normally you may have nothing more than a bad temperature sending unit. If the engine is truly running cold, the heater will obviously be cold also.

 

[AaronHulst]

The heater is working normaly. Wouldent it throw an error code if the tempature sending unot was bad?

 

[avisitor]

Not all things are monitored by ECM
Only the very important ones
And sometimes even then it may not throw a code