Thermostat/P0128 Troubleshoot

[mango]

Hey - new this to this forum, searched around to hopefully avoid a redundant question, but could not find anything specifically.

I just got a 2005 X, noticed it was taking longer than I expected to reach operating temperature. Also taking into consideration the VQ40 is a larger engine than I have ever owned - i was not sure 100% what I should expect.

Then I received a notice light code P0128 which indicated that infact the time lapsed between start and reaching optimum temperature was too long. The temperature gauage even after driving for over an hour hovers at about the 40% mark (this could also be normal, although most cars I have go to 50% of the gauge and sit there).

Is the thermostat stuck open? Is a sensor buggered? I cleared the code and will monitor it going forward.

Possible symtoms:
- air in system - check that this morning when cold, fluid in radiator right to the top.
- thermostat needs to be replaced
- another sensor?

Anybody else experieced this? Thanks for the help!

[Revu]

Typically a P0128 is the Thermostat is stuck open.

My 05 threw that code and the rubber grommet that formed a seal on the thermostat had warped and wasn't allowing it to shut, which in turn was causing it to take forever to reach operating temperature.

So if it seems as though it's taking a while to warm up chances are it's the thermostat over the sensor that's tripping the code.

Fortunately running too cold is better than running too hot, but you'll still want to get that changed out pretty soon.

Good luck!

[mango]

Thanks for the information!

[Chef]

If your engine runs to cold then you can sludge it up and then you will really be screwed. It's either the Ect sensor (not it) or thermostat (this is it).

[Itsme]

Also replace your radiator cap. I am sure it is ready!

[mango]

thanks for all the feedback. i will be looking at it right away, trying to get the dealership i bought it from to do something, doubtful but worth a shot.

thanks!

[ShiftingSkys]

Stand firm! Maybe you will get it free.