99 heat gauge not reading above 150ish

I Tesed the coolant temp sensor a week ago after seeing poor heat in the cab. Tested once cold, then after a drive, it Tested ok. Unless I hit the highway it won't get to 175.???

Heater hoses are hot so thermostat isn't stuck.

Anyone have a link for how hot the air from the vent should be?

4x4JeePmaNthINg said:

Heater hoses are hot so thermostat isn't stuck.

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Test the thermostat correctly and you will likely find the root cause for the symptoms described. You should have discovered this when you originally researched the problem.

4x4JeePmaNthINg said:

Heater hoses are hot so thermostat isn't stuck.

Click to expand...

The heater hoses are always hot because there is no control valve and it bypasses the t-stat.

Tim_MN said:

Test the thermostat correctly and you will likely find the root cause for the symptoms described. You should have discovered this when you originally researched the problem.

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Fair enough sir, however can you tell me what I should expect out of the vents for temperature with a working thermostat?
Use like to see if the blend doors are leaking, everything seemed good condition last time I pulled the dash.

I'll dig out the tstat see what's up.

I don't have an IR temp gun, but I keep meaning to buy one. With a properly functioning thermostat and a clean heater core you should have plenty of heat.

4x4JeePmaNthINg said:

Heater hoses are hot so thermostat isn't stuck.

Click to expand...

RCP Phx said:

The heater hoses are always hot because there is no control valve and it bypasses the t-stat.

Click to expand...

The hose going from the head to the heater core should be SIGNIFICANTLY hotter than the return hose, with the heater blower running. If not, your heater core is not transferring enough heat. You can validate this with your bare hand.

As an aside, one bitter cold winter, I had an otherwise functioning vehicle suddenly not heat up. My (then) FIL told me the thermostat was likely stuck open and to put cardboard in front of the radiator, exposing only the top 3 or 4 inches to airflow. I experimented with that air gap and found I could regulate the engine temperature well enough to get through the week, and out to his shop when I had the supplies and time to open the cooling system.

Tim_MN said:

I don't have an IR temp gun, but I keep meaning to buy one. With a properly functioning thermostat and a clean heater core you should have plenty of heat.

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New tstat and she is reading correctly as per your advice. I didnt bother testing the old one as a New one is cheap, and my original thought of The temp sensor reading poorly wasn't the issue. As hypoid mentioned, the top hose in my case was not hotter, but they were equal on temp. I assumed the spring grew weak and it opened too low of temp as the radiator was warm to, not hot as it should have been.
The heat is much better than it was. I Wasn't sure if there even is an expected factory temp from the vents. Heater core was replaced two years ago. on floor heat I get air from the side defrost vents, but not the windshield vent until defrost is selected, i don't think that's normal hahaha. None the less the settings work.
The never ending fix it battle continues.

Anyhow thank you for the help

The FSM says that the dashboard vents should be about 50 degrees cooler than thermostat housing and that has been my experience as well.

IR gun on the thermostat housing should be in the 195-200 range after full warm-up