Temp problems

[Justin S]

Where does the needle sit when you first start up, below 100?

 

[98nightmare]

Yeah, bottom of the 100 mark

 

[Dylan1991_1500]

Mine does the same thing. It will spike at 240 then drop to just over 210 and stay there the rest of the time. I suspect the gauge is off so I bought an infrared temp gun and plan on replacing the oem gauge at some point. Haven't tested it with the gun yet because it's all apart on jeckstands right now.

 

[98nightmare]

Idunno..lol
I'm at a complete loss on this one. I haven't had a 350 in ten years, my 98 is a 4.3.. this 95 K1500 is for my daughters 16th birthday. Been so focused on getting it running and looking good, I never drove it. Started out with bad injector and fuel pump.. then it'd crank/ rev and run fine.. never ran it very long after that till I had to hide it from her at someone else's house. Now dealing with this annoying temp problem
Gotta give it to her not this weekend but the next..

 

[98nightmare]

I'll try swapping out the thermostat and see what it does tomorrow night

 

[sntrym]

Before you swap out the tstat, I would check on the radiator cap. The collapse of the hose tells me that when the coolant cools, the pressure is not being released. In this case, the coolant in the overflow tank should be flowing back into the system via the vacuum created as the system cools. It doesn't sound like it's doing that.

When you flush the system, are you getting full flow from the top of the radiator down to the bottom? How about from upper radiator hose to the radiator cap? If you have some blockage, you might see this if the piece blocking is restricting flow one way, and then completely blocking it when the vacuum is created, similar to a check valve.

 

[Ironhead]

Just what sntrym says. For your daughter you want a truck that is not going to strand her somewhere. The rad cap is cheap and so is the T'stat. I'd change both, just for insurance. If the temp gauge still reads high, borrow an infrared thermometer, and shoot the area by the thermostat housing. If it is still hot, well, it is possible that the rad is partially blocked, or the water pump impeller is not doing the job, again, not terribly expensive to fix either of theses.

If still not right, a combustion gas test, as suggested earlier in this thread is the next step.

Good luck, and keep us posted.

 

[98nightmare]

Flushed radiator again, put in a new lower temp thermostat and a new radiator cap.
........now it only goes to just below normal

All that and it was probably just the radiator cap..lol
At least now I have less to worry about since everything is now new. And being just below normal is probably a good thing since she'll be picking up her younger sisters from school in it. It'll be sitting and idling a lot..lol
Man, you guys are the greatest! I really do appreciate everyone's help and quick responses!
Feel like a ton of stress has been lifted y'all!
Again, Thank you guys!!!!

 

[Justin S]

No problem, love to help, see we're not assholes all the time!