erratic temperature guage - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jim ellis · 07-27-2014, 06:25 PM

my temperature guage will read normal at slow speeds but goes to cold on high speeds.even reads the same running the a/c

**TBONE1964** · 07-27-2014, 06:44 PM

What you describe sounds like a normal condition for these trucks. When you are moving at 50-60 mph, you get much more air flow through the radiator which helps cool the coolant. If you are just sitting at an idle, it is normal for the temp to be higher because there is no air flow.

You won't really notice a big difference in temp with the A/C on or off. The A/C compressor only robs about 20 horse power form the engine. That will effect your fuel mileage but not your temp.

Hope this helps.

Oldtruckfanatic · 07-27-2014, 07:13 PM

Just to add to what TBONE said. If your truck doesnt have a fan shroud it exaggerates the difference.

_Ogre · 07-28-2014, 11:22 AM

do you have a thermostat in it?
driving 60 mph on a sub-zero day your truck should still be in the normal range
check your thermostat; it may be missing or stuck open

07-27-2014, 06:25 PM	#1
jim ellis Registered User Join Date: Oct 2012 Location: maple valley wa Posts: 46	erratic temperature guage my temperature guage will read normal at slow speeds but goes to cold on high speeds.even reads the same running the a/c

07-27-2014, 06:44 PM	#2
TBONE1964 Cluster King Join Date: Nov 2012 Location: Junction City, OR Posts: 5,263	Re: erratic temperature guage What you describe sounds like a normal condition for these trucks. When you are moving at 50-60 mph, you get much more air flow through the radiator which helps cool the coolant. If you are just sitting at an idle, it is normal for the temp to be higher because there is no air flow. You won't really notice a big difference in temp with the A/C on or off. The A/C compressor only robs about 20 horse power form the engine. That will effect your fuel mileage but not your temp. Hope this helps. __________________ Contact me on all of your gauge cluster needs. I specialize in restoration, repair and parts sales for 67-72 Chevy and GMC trucks. email me at tbonegarris@yahoo.com I am also a dealer for Counterpart for gauge cluster parts only. Also see my facebook page, CG&C

07-27-2014, 07:13 PM	#3
Oldtruckfanatic Truck junkie Join Date: May 2006 Location: Reno NV Posts: 697	Re: erratic temperature guage Just to add to what TBONE said. If your truck doesnt have a fan shroud it exaggerates the difference.

07-28-2014, 11:22 AM	#4
_Ogre Registered User Join Date: Jan 2012 Location: Motown Posts: 7,677	Re: erratic temperature guage do you have a thermostat in it? driving 60 mph on a sub-zero day your truck should still be in the normal range check your thermostat; it may be missing or stuck open __________________ cool, an ogre smiley Ogre's 58 Truk build how to put your truck year and build thread into your signature shop air compressor timer



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