1995 GMC Truck Engine runs 160 degrees

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1995 GMC TRUCK
V8
2WD
AUTOMATIC
189,000 MILES

I changed my radiator in my GMC Truck, 350 engines and afterwards the temperature will not get above 160 degrees. It is affecting my engine performance and gas mileage. I have changed my t-stat and temperature sensing unit and it still runs at 160 degrees. I made sure the t-stat was a 195 degree as well. When I replaced the radiator it appeared to be exactly the same. Everything fit perfect, the thickness, width etc. Was the same. Is it possible I got the wrong radiator?

Oh, I have also noticed problems with my transmission not wanting to shift since the cooling problem started and the engine idles up when this happens. After I stop the engine and wait a while, it runs normal. I may do this once every couple of weeks.

Any help would be greatly appreciated.
Thanks,

Todd

5 Replies

JDL

MECHANIC
16,098 POSTS

The replacement radiator, was it new, Oem replacement? I'd have to double check the engine temp, your gage may not work correctly. Is there circulation through the radiator? Do the heater hoses, get hot? Any applicable trouble codes?

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Friday, March 19th, 2010 AT 1:32 PM

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No, it was not OEM. I checked the temperature of the engine where the thermostat house is with an infrared thermometer and it read around 170 degrees. I noticed the radiator cap does not seem to be getting hot at all, even after I have driven for 1/2 hour. The radiator hose registered around 140 degrees going leaving the radiator. I am going to see if any trouble codes show up this weekend.

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Friday, March 19th, 2010 AT 2:31 PM

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Sorry, it was a new radiator, but not from the dealer.

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Friday, March 19th, 2010 AT 2:41 PM

JDL

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Is the radiator cap new? What is the pressure reading on the cap?

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Friday, March 19th, 2010 AT 3:02 PM

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No, the radiator cap is not new. In fact, it is probably 8 to 10 years old. I do know that there is pressure on the hoses and coolant pulls into the radiator from the overflow tank.