Bad thermostat?

[mendozer]

This past week I noticed my air isn't as hot when I warm up the car in icy mornings. It used to get real hot in about 2-3 minutes and now it'll be 10+ minutes before it's warm. I also don't turn it down like I used to, indicating it's not reaching the same temperature.

Fan turns on, coolant levels fine, but I did notice the upper radiator hose is warm and the lower is cold after driving for say 20 minutes. My temp gauge isn't fluctuating on the dash (although it's also 35-40 degrees outside).

what's the deal?

 

[BrianK14]

Temp gauge isn't fluctuating? Does that mean it's in the middle where it should be, or that it doesn't move off 'cold'?


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[jgue467]

If it's old it may be sticking part way. I found mine OEM one was sticking about 5-10% before full open. You wouldn't notice under Most conditions except the Extreme ones like 105+ idling for and hour or stop/go with a trailer.

In your case, the Extremes would be the opposite but the effects are felt. Its a cheap, easy part to replace. Luck and enjoy. :cowboy:

 

[mendozer]

Starts cold then moves to middle. Idk why the lower hose isn't warm.thats weird to me

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[reelamin]

Bad Thermostat! Mine didn't have one in it when I bought it 30k ago. Exact same problem. Slapped in a NAPA Thermo....has worked perfectly ever since. Sans blown radiator recently.....pulled it....checked system....put it back...working just like new for the last 200 miles. I saw -10 last night and we go over 100 in the summer so mine sees all kinds of weather.

Perfect time to flush the entire system and start fresh!

BUUUUUT check this first. Mine was working fine as I said. Last year my buddy on a hunting trip kicked loose the control cable on the passenger side. The control cable came off the temp control. Just had to put it back "bent attachment' that feed into a hole in the arm. WAM BAM....heat was back. I was able to see this when the heater control valve would not move while diagnosing problem. A laser thermometer really helped tell me where I had hot water and what temp and where I didn't!

 

[csp]

Feel the heater hoses instead of the radiator hoses. Coolant will flow through the heater hoses whether the thermostat is allowing coolant to flow to the radiator or not.

 

[mendozer]

OMG i was totally thinking the heater hoses were the radiator hoses haha. brain fart. I'll check that tomorrow. Got a long drive to the mountains for skiing so I should have plenty of time.