OverHeating, just started two days ago

[YerpDerp_1]

I have a 1997 with a 5.9 magnum engine and when i drove to work the truck was fine. I let one of my delivery drivers borrow my truck because her car was sputtering on her. It was fine when i gave the truck to her and when i got it back i noticed the engine was getting hotter than normal. It was also 93 degrees for the first time since I've owned the truck. When i turn the heat on all the way to circulate the truck the temp returns to 200 degrees but as soon as i accelerate to quickly or turn off the heat, it shoots up to around 235 to 250 degrees. Both heat and AC work great on this truck. I'm thinking water pump, thermometer, or maybe radiator flush but before i do anything i was hoping for a second opinion. I bought the truck in the dead of winter, and the worst I've had to replace so far are U-Joints. This is the first serious problem with the truck since I bought it. I've kept up on all my oil changes with Max Life 5w30 Synthetic blend. I have not done any fluid flushes at all. I'm also missing the coolant overflow cap. The owner sold it to me with gorilla tape over where the cap should be. It hasn't been a problem so far, but maybe that's affecting it?

Lastly, i forgot to add, its at 163,033 miles. Maybe its just showing it's age?

 

[Kickkem]

I have a 98 with a 5.2. I recommend you make certain the radiator is completely full. The system is designed to flow some fluid to the reservoir when it is hot and suck it back in as it cools, controlled by the radiator cap, which I would change right away, it is cheap.

The cap on the reservoir is unimportant as the fluid move in and out off the bottom. I have had to change my water pump but it was leaking out the weep hole, easy check.

A flush and a thermostat change is pretty easy, once you remove alternator and a/c unit and brackets. While you are in there be sure to change the bypass hose. My coolant sending sensor needs replaced so you made need to test or replace yours.
Good Luck!

Kick

 

[YerpDerp_1]

I just took a drive and let the truck do its thing and the heat was reading about 235 and then it went down to almost 200 on its own. 200 is where it pretty much always was after warming up until now. Could it mean the thermostat is on its way out?

 

[TMyers]

I just took a drive and let the truck do its thing and the heat was reading about 235 and then it went down to almost 200 on its own. 200 is where it pretty much always was after warming up until now. Could it mean the thermostat is on its way out?

Either the thermostat or the water pump is not pumping enough. If the water pump is the original, I would change them both.

 

[YerpDerp_1]

Sounds like a good start, I'll give that a shot. Probably gonna take me a few days between work and this heat. fingers crossed

 

[YerpDerp_1]

Okay, so after i drove the truck for a bit i let the heat rise and then it dropped to around 210 and its been hanging around there just fine. It doesn't go any higher except for maybe 15 seconds tops to about 215 and then it drops back down. I'm not sure what to think of it but the trucks been driving just fine. I haven't done anything yet

 

[dapepper9]

Pull the belt off, grab the fan and wiggle up and down. If there's movement it's definitely bad. If not, might do the tstat and see how it goes

 

[Khoover1988]

Just be safe, dont blow a head gasket. Its cheap enough, change tstat and waterpump, do a good radiator flush and back with fresh coolant. Put a 180degree tstat in. I have it in mine and in the dead heat of the summer it never goes over 195degrees. Good luck!