Gabrielle McCart

Hello i have a 98 chevy k1500 4x4 5.7L V8 pickup and it broke down nearly a year ago. We haven't been able to get it to run since. I've replaced the waterpump, flushed the radiator, replaced the idler pulley, and the thermostat but it still starts getting hot as soon as you start it. The coolant level hasnt decreased any so I don't think it's leaking. Can somebody please help me. I need led in the right direction.

kevinkpk

First, how hot does it get, and are you sure it is getting hot?

Gabrielle McCart

My boyfriend thought it was just the thermostat in backwards so he flipped it around and it made it read right of course. It took a few mins to reach the middle of the gage but then it slowly started getting hotter. He said theres air in the line and he was trying to get it out but i had to shut the truck off cause it was almost to the red. I don't know if the heads cracked or what. He said the hoses are fine and we flushed the radiator yesterday and ran clear water through it fine so its not clogged up, right?

SBchevyfan

I would try checking your temperature in some other way than you dash gauge. It could be a bad sensor or simply an air pocket at the sensor.

Gabrielle McCart

How do I do that

kevinkpk

Get a thermometer.

SBchevyfan

Start by making sure the coolant is full. Loosen the temp sensor enough to allow air and water to escape, When no more bubbles come out the air should have been removed. Tighten the sensor prior to the engine cooling to keep air from re-entering the system. Let the engine cool. Then remove the temp sensor and attach a mechanical temp gauge in it's place. On my S-10 I had to keep the temp sensor attached to the wiring harness to get the engine to start, just set it someplace it won't be in the way or be damaged. If your temp is good when you run the engine up to operating temp, It may have been air in the system or a bad sensor. Re-install the sensor and start the engine again. If you still have the climbing temps, replace the sensor. If your temp continues to rise with the mechanical gauge installed. You have other issues.

Another option would be to use an infrared thermometer. Remove the thermostat and re-install the thermostat housing and upper radiator hose. Make sure the coolant level is good. Start the engine and wait for the upper radiator hose to get warm. Start taking temp readings using the infrared thermometer at the thermostat housing, should be fairly close to what the engine temp at the sensor should be. The reason I would remove the thermostat is that it sits housing were I want to take the temp readings and I don't want the thermostat to influence the readings. Compare the infrared readings with what you are seeing on the in-dash gauge.

Panda760

I would check the coolant level and also visually inspect if the radiator and/or radiator hose is cracked/leaking.