Sorry if this has been asked before, but I'm in a bit of a pinch for time.

Today I was driving and saw that my coolant temp. gauge was slowly getting hotter and hotter. It eventually got to the point where the check gauges light turned on and I shut it off for a bit. After about five minutes, I turned it back on and it immediately began overheating again. I pulled into a parking lot and opened the hood. I felt the radiator cap and it was cold, like the engine was never on. The upper radiator hose was hot like normal, however.

I touched the radiator cap which probably turned it a bit and the cap shot off, spewing coolant everywhere. I assume this was because of the pressure though and isn't really an issue.

I added water to the radiator, but it didn't take very much to fill it up. As I nursed it back home, I turned on the heat just to see if it made a difference. Sure enough, there was no heat blowing out when there definitely should have been.

So, I'm not exactly sure what I should do first. I'm really hoping that it is just the thermostat that's gone bad, but I'm not much of a mechanic so I'm just guessing.

I was hoping someone here would be able to either confirm my opinion or point me in the right direction (water pump, coolant pump?).


1999 Dakota Sport
3.9
Auto
4x4

 

I'm not really sure, but if you want to replace the thermostat they are only $10-$15. I would probably do that to begin with.

 

agreed. And see if you can find a fail-safe one...they fail open rather than closed.

 

ok so last may long camping trip i went off roading and well lets say i went through a 4 foot mud pit and made it but after that just a little way down the road i had the same problem. after not being able to diagnose it nor able to drive it home, called the tow truck got her to the dealership then the next work day got a call saying mud seized up my fan, that was it to 500$ dollar car wash later and it was good as new.
i think all they did was flushed the coolant system and the labour for the cleaning thats all that was on the work order.

 

Thanks for the help guys.

I believe the first thing I'm going to do is flush the coolant system. I figure since the thermostat has to be removed to flush the coolant system I'll go ahead and change it out too.

Hopefully that works.

There shouldn't be any issues with my fan because it still turns when the motor is on and my engine bay is probably cleaner than most of the trucks I've seen posted on here. There is the possibility that something is wrong with the fan, however...

 

I figured out my issue.

I went to flush the coolant system, so I removed the thermostat. I pulled it out and it was covered in a nasty green and brown liquidy mixture. It may have once been coolant, but I couldn't be too sure. This led me to believe that the coolant may have never been flushed since the truck was made (and at 140,000 miles, GAH!). I replaced the thermostat with a 180 degree and put in new fluid.

I drove it pretty quickly after I finished the flush, but it was still overheating so I figured it had to be the water pump. So the next morning I went to drive it to the shop and had no overheating issues. I drove around for another thirty minutes or so and still had no overheating. So my guess is that there was an air bubble somewhere in the coolant system and changing the fluid got rid of it.