Is my temperature gauge broke? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

71400lb · 07-26-2005, 09:02 AM

I have a 71 c/20 with a rebuilt 400 small block Chevy 4 bolt main. I was told when I bought the truck, that the motor came out of a 72 Nova, but apparently 72 Nova's never came with 400 SBC's.

Anyway, the guy I bought it from said he removed the thermostat and put in what he called a "restrictor plate" instead! So it has no thermostat.

The truck has been fine for the past year, but today I noticed my temperature gauge was all the way over to the "C" on the left. I drove all the way to work(18 miles) at 79 degrees outside, and the gauge never moved!

When I shut the truck off at work, I noticed when I insert and turn the key clockwise just before the "start" position, the gauge needle moves quickly all the way to the left, like it should,,,so power IS getting to it...and when the truck is started the needle just stays at "C".

Should I be concerned? What's your theory?

Thanks
71400LB

1971 3/4 Ton 2wd
400 SBC/4 bbl Quadrajet
3.73 Open

67chevemall · 07-26-2005, 09:39 AM

sounds like the sensor.
There was just a post on this, I'll see if I can find it.

71400lb · 07-26-2005, 09:42 AM

much appreciated,

Thanks

67chevemall · 07-26-2005, 09:50 AM

http://67-72chevytrucks.com/vboard/s....php3?t=165544

I can't get mine to move at all. I hope we can solve the problem.

67chevemall · 07-26-2005, 09:51 AM

A quick test you can do to see if the gauge and wiring are working is to turn you key in the "on" position, disconnect the green wire from the temperature sender, and short it against the housing of the temperature sender. The gauge needle should go way up to the H position. If it does, then chances are that your gauge and wiring are fine.

71400lb · 07-27-2005, 11:30 AM

Okay, dumb question, but where is the temperature sensor and what does it look like? Can I pick one up at AutoZone or is it a special order thing?

Thanks,
71400LB

A.P. · 07-27-2005, 11:53 AM

On the 350 engine the temperature sensor is located on the driver side. And its between the 2 front spark plugs.

71400lb · 07-27-2005, 01:26 PM

Thank you for the quick response and picture too!
Well, mine is a 400 small block Chevy, but it's probably the same thing as a 350 anyway...I will check it asap...thanks again.

71400LB

71400lb · 07-27-2005, 02:38 PM

I FIXED IT!
Thanks all for your input, the picture was especially helpful. I found the sensor and sure enough the green wire going to it had broken completely off! So on my lunch hour, I spliced in a new piece of wire and black-taped it all snug and VOILA, the temp gauge works perfectly again!

Thanks again,
71400LB

panhandler62 · 07-27-2005, 02:49 PM

I see you have one of those custom single exhaust port 350s.. wink

Mad Dog · 07-27-2005, 04:09 PM

Quote:

Originally Posted by panhandler62

I see you have one of those custom single exhaust port 350s.. wink

It took me a minute to figure out the picture.......God, I'm dumb sometimes

byrd · 07-27-2005, 05:58 PM

Quote:

Originally Posted by panhandler62

I see you have one of those custom single exhaust port 350s.. wink

A.P. · 07-28-2005, 10:18 AM

Hahahahahaaaa...
panhandler62 the way gas prices are going, I can afford to run one piston.

07-26-2005, 09:02 AM	#1
71400lb 71400lb Join Date: Jun 2004 Location: Charlotte NC Posts: 74	Is my temperature gauge broke? I have a 71 c/20 with a rebuilt 400 small block Chevy 4 bolt main. I was told when I bought the truck, that the motor came out of a 72 Nova, but apparently 72 Nova's never came with 400 SBC's. Anyway, the guy I bought it from said he removed the thermostat and put in what he called a "restrictor plate" instead! So it has no thermostat. The truck has been fine for the past year, but today I noticed my temperature gauge was all the way over to the "C" on the left. I drove all the way to work(18 miles) at 79 degrees outside, and the gauge never moved! When I shut the truck off at work, I noticed when I insert and turn the key clockwise just before the "start" position, the gauge needle moves quickly all the way to the left, like it should,,,so power IS getting to it...and when the truck is started the needle just stays at "C". Should I be concerned? What's your theory? Thanks 71400LB 1971 3/4 Ton 2wd 400 SBC/4 bbl Quadrajet 3.73 Open

07-26-2005, 09:39 AM	#2
67chevemall Registered User Join Date: Apr 2003 Location: NB Posts: 3,367	sounds like the sensor. There was just a post on this, I'll see if I can find it. __________________ 1968 Chevy C10 307 3ott fleetside 1967 Chevy C/10 V8, 3spd, fleetside lwb.Sold 1967 Chev C/10 step, 383, M21. SOLD

07-27-2005, 11:53 AM	#7
A.P. Black 72 Chevy Join Date: May 2002 Location: Los Angeles, California Posts: 662	On the 350 engine the temperature sensor is located on the driver side. And its between the 2 front spark plugs. Attached Images

07-27-2005, 02:49 PM	#10
panhandler62 Java Mechanic Join Date: Jun 2005 Location: Martinsburg, WV Posts: 6,764	I see you have one of those custom single exhaust port 350s.. wink __________________ Keith 11 Lincoln MKT -- Momma's wagon 13 G37xS -- middle age crazy car 68 C20 Fleetside -- RIP Decorating the whole town up at a cost of $27 ....

07-26-2005, 09:42 AM	#3
71400lb 71400lb Join Date: Jun 2004 Location: Charlotte NC Posts: 74	much appreciated, Thanks

07-26-2005, 09:50 AM	#4
67chevemall Registered User Join Date: Apr 2003 Location: NB Posts: 3,367	http://67-72chevytrucks.com/vboard/s....php3?t=165544 I can't get mine to move at all. I hope we can solve the problem.

07-26-2005, 09:51 AM	#5
67chevemall Registered User Join Date: Apr 2003 Location: NB Posts: 3,367	A quick test you can do to see if the gauge and wiring are working is to turn you key in the "on" position, disconnect the green wire from the temperature sender, and short it against the housing of the temperature sender. The gauge needle should go way up to the H position. If it does, then chances are that your gauge and wiring are fine.

07-27-2005, 11:30 AM	#6
71400lb 71400lb Join Date: Jun 2004 Location: Charlotte NC Posts: 74	Okay, dumb question, but where is the temperature sensor and what does it look like? Can I pick one up at AutoZone or is it a special order thing? Thanks, 71400LB

07-27-2005, 01:26 PM	#8
71400lb 71400lb Join Date: Jun 2004 Location: Charlotte NC Posts: 74	Thank you for the quick response and picture too! Well, mine is a 400 small block Chevy, but it's probably the same thing as a 350 anyway...I will check it asap...thanks again. 71400LB

07-27-2005, 02:38 PM	#9
71400lb 71400lb Join Date: Jun 2004 Location: Charlotte NC Posts: 74	I FIXED IT! Thanks all for your input, the picture was especially helpful. I found the sensor and sure enough the green wire going to it had broken completely off! So on my lunch hour, I spliced in a new piece of wire and black-taped it all snug and VOILA, the temp gauge works perfectly again! Thanks again, 71400LB

07-28-2005, 10:18 AM	#13
A.P. Black 72 Chevy Join Date: May 2002 Location: Los Angeles, California Posts: 662	Hahahahahaaaa... panhandler62 the way gas prices are going, I can afford to run one piston.



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