thermostat stuck open question

[Tannerm]

My 99 explorer 5.0 is throwing a CEL (states stuck thermo or bad sensor) and the engine temp gauge doesn't budge off cold. The heater in the car is Luke warm. So I guaranty its a stuck thermo. My only question is, this shouldn't be detrimental to the truck correct? I won't be able to fix it till after xmas. Just making sure I'm not jacking up something with my wife driving it.

[jw33]

Fuel mileage will probably go down a bit and it isn't good for the oil.

[jakesford]

The ECU will be stuck in open loop since the engine isn't getting up to temp...

[YALE]

Just put a new thermostat in. They're easy.

[BP]

Eventually you'll get tons of carbon buildup and the associated drivability problems that come with it, plus what JW33 said.

[Jewrrick]

It's like $15-$20 and only takes an hour or two to change if you have never done one.

[JimD]

Could also be an airpocket in the cooling system. IMO fix it b4 its driven again.

[The King]

Could also be an airpocket in the cooling system. IMO fix it b4 its driven again.

Air pockets cause overheating rather than causing the engine to not reach operating temp.

[Tannerm]

Sorry. Been a busy work week... Since I wrote this, the truck hasn't been driven. Yale, I haven't had a day off to change her. But Ive dozens so I'll do her soon after xmas.