Coolant temperature sensor failure

Driving over the mtns today and 200yds from the top hood started smoking. Gauge on cab never moved.

Opened hood and coolant reserve tank cap was blown. Bubbling coolant spraying everywhere.

Let it cool down and was able to coast in N to town and got to a Autozone. Code thrown was faulty temp sensor. Gauge in cab never moved.

Tried starting car and it wouldn’t for a few times the finally got it to go. Tried to get it to the mechanics a few miles away, but every light we hit it would die. Finally wouldn’t restart and had to get a tow.

Small hose on the left (if looking in from front of truck) connected to radiator literally melted.

Truck sounded like a diesel and had a grindy clickey sound when pressing on the gas during this last point.

How f’ed am I?

P.S.
2007 4x4 v6 250k
Had enough oil and coolant but I don’t think the coolant was getting pushed through?

 

Sorry man.

That’s bad man.
I hate to hear it.

If it got that hot, I bet the head gasket(s) are gone.

You caught a case of bad luck.
A bad temp sensor and an over heating engine.

Did you ever have a check engine light before this? I’m just wondering if the sensor has been bad for awhile?

 

No cooling in an engine with lots of machined aluminum castings. Not a good combination. Should have shut her down at the first sign of overheating. Sorry, but she's probably mortally wounded.

 

Nope, no CEL ever. Zero issues before this. I wouldn’t have even know if it wasn’t for the coolant smoking off the engine.

 

I know this won't make you feel any better, but 250,000 miles with no problems is pretty damn impressive. She served you well.

 

Family friends vehicle. I only had her for about 3 years. But yeah, it was a good truck. Seems silly a $10 part will destroy a truck.

would it be worth it to get head gaskets replaced or is the engine shot? Does that mean coolant mixed with the oil?

This is above my pay grade on every level

 

If it got so hot the engine was knocking and things melted the engine is probably beyond saving unfortunately.

 

What is the going rate for a engine and labor for install these days?

Found a rebuilt one close by for $4k

 

Would never say I told you so, cause it sucks, but next go round look into getting an ultra gauge or scan gauge to monitor key operating parameters.

 

If the coolant temp sensor was faulty would the scangauge have been able to read the temp accurately?

 

No

 

if my dash gauge is basically locked in the midpoint always, is there value for me to observe temperatures via OBDII?

 

You can watch engine coolant temp.

I believe what happened to the OP here is that they lost so much coolant so quickly that it dropped below the temp sensor so it no longer could effectively read engine temperature (and thus the gauge didn't indicate an overheat) because it is mounted in the coolant crossover manifold on the 4.0L not in the engine block or cylinder head.

 

I get that the coolant temp may not have moved on the scan guage, but perhaps the transmission fluid temp would have started to rise? If the radiator is hot, would the trans fluid not start to heat up as well since it goes thru/close to radiator?

Post like this makes me want to invest in an oil pressure/temp guage via sandwich plate. Might have seen it coming with elevated oil temp as well?

 

Not if there's no longer any coolant circulating through the radiator.

Yea probably as hot as this one got you would see extremely high oil temp, weather you would catch it in time before there was damage is debatable.
If your one that is aware of things, keeps and eye on gauges, and notices smells and sounds there's a good chance you would catch a problem.
Most of the time this kind of stuff happens when people ignore the warning signs and/or think they can make it that last couple miles instead of pulling over and checking things/getting a tow.

 

By the time the engine loses OP or the tranny temps skyrocket from the engine's high temps the motor damage is done.