Temperature gauge sensor/'70 pickup - The 1947 - Present Chevrolet & GMC Truck Message Board Network

grega57 · 04-02-2006, 10:18 PM

I'm replacing the old standard dash with a refurbished gauge cluster. The old unit just had an idiot light for temperature. The new one has a gauge so I had to change the sensor to one that talks to the gauge instead of the light. My problem is that both O'Reilly and Advanced Auto both sell a replacement sender that is too big for the port on my 1970 Chevy Pickup. It has a 307 which I guess is suppose to use the same size as the 350. Does anyone know why these parts stores are selling a unit for this engine that isn't the right size? Where can I get the right one? Thanks, Greg.

*rage'nrat638* · 04-02-2006, 10:43 PM

i am sure i have a used one..pm me if you want one mark

also have the stock oil line needed for the gauge to the engine listed on the parts board

byrd · 04-02-2006, 11:08 PM

I have a brand new a/c delco one here and it is GM part # 12334869 I would try the dealership to get the right part and they are really cheap. IIRC I paid about $10 for mine. Randy

grega57 · 04-02-2006, 11:21 PM

Thanks Mark and Randy. I'll check with the Chevy dealer tomorrow. It's just strange that the parts stores are selling a unit that doesn't fit.

**pjmoreland** · 04-03-2006, 12:03 AM

Are your heads original to the truck? If they are from a later year, then that might be why the temperature sensor doesn't fit. I had to mount my sensor in my thermostat housing because my heads are not the originals.

byrd · 04-03-2006, 07:26 AM

Good point PJ, greg you may need to pull one of the valve covers to get the casting # off of it. Randy

Hook'em · 04-03-2006, 03:11 PM

I just bought one from a board member and he said I would need a brass reducer to make it fit. Now I have to find a brass reducer.

**pjmoreland** · 04-03-2006, 03:19 PM

The correct sensor for a gauge should look like this, and should use a 13/16" socket to install.

grega57 · 04-03-2006, 08:44 PM

Thanks to all of you that have responded. I've pulled the old idiot light sensor and measured the hole at 5/8" diameter. The sensor that is suppose to be the replacement part fills a threaded hole that measures 3/4". The sensor I pulled has a number on it, "HS125CM 2639". I checked with GM and they say it's not their part. I've found a sensor that will fit but it is a Ford part so I'm guessing it won't work.

Greg

byrd · 04-03-2006, 09:29 PM

Greg,
PJ has got the easiest fix for you, just plud the temp sensor hole up and replace your water inlet with one that will accomodate the sensor there. I know there are found on late model Chevy but I'm not sure what years to use. Hopefully PJ will chime back in and LYK what all he did to remedy the problem. Randy

**pjmoreland** · 04-03-2006, 10:59 PM

Quote:

Originally Posted by byrd

Greg,
PJ has got the easiest fix for you, just plud the temp sensor hole up and replace your water inlet with one that will accomodate the sensor there. I know there are found on late model Chevy but I'm not sure what years to use. Hopefully PJ will chime back in and LYK what all he did to remedy the problem. Randy

Well it may not be the most elegant solution, but I used the thermostat housing from an '83 Caprice Classic. There was a hole in the housing for some sort of temperature-controlled vacuum valve. The hole was the perfect size for my temperature sensor.

Tx Firefighter · 04-04-2006, 06:59 AM

The stock sensor is 1/2 N.P.T. threads. It sounds like you have later model heads if the hole is too small.

04-02-2006, 10:18 PM	#1
grega57 Registered User Join Date: Apr 2006 Location: Kansas Posts: 11	Temperature gauge sensor/'70 pickup I'm replacing the old standard dash with a refurbished gauge cluster. The old unit just had an idiot light for temperature. The new one has a gauge so I had to change the sensor to one that talks to the gauge instead of the light. My problem is that both O'Reilly and Advanced Auto both sell a replacement sender that is too big for the port on my 1970 Chevy Pickup. It has a 307 which I guess is suppose to use the same size as the 350. Does anyone know why these parts stores are selling a unit for this engine that isn't the right size? Where can I get the right one? Thanks, Greg.

04-02-2006, 10:43 PM	#2
rage'nrat638 Account Suspended Join Date: Mar 2003 Location: THE FALL GUY CHICAGO IL Posts: 5,883	Re: Temperature gauge sensor/'70 pickup i am sure i have a used one..pm me if you want one mark also have the stock oil line needed for the gauge to the engine listed on the parts board Last edited by rage'nrat638; 04-02-2006 at 10:44 PM.

04-02-2006, 11:21 PM	#4
grega57 Registered User Join Date: Apr 2006 Location: Kansas Posts: 11	Re: Temperature gauge sensor/'70 pickup Thanks Mark and Randy. I'll check with the Chevy dealer tomorrow. It's just strange that the parts stores are selling a unit that doesn't fit.

04-03-2006, 12:03 AM	#5
pjmoreland Senior Member Join Date: Jan 2005 Location: CA Posts: 5,426	Re: Temperature gauge sensor/'70 pickup Are your heads original to the truck? If they are from a later year, then that might be why the temperature sensor doesn't fit. I had to mount my sensor in my thermostat housing because my heads are not the originals.

04-03-2006, 03:11 PM	#7
Hook'em Senior Member Join Date: Jul 2004 Location: Round Rock, Texas Posts: 858	Re: Temperature gauge sensor/'70 pickup I just bought one from a board member and he said I would need a brass reducer to make it fit. Now I have to find a brass reducer. __________________ Hook'em

04-03-2006, 03:19 PM	#8
pjmoreland Senior Member Join Date: Jan 2005 Location: CA Posts: 5,426	Re: Temperature gauge sensor/'70 pickup The correct sensor for a gauge should look like this, and should use a 13/16" socket to install. Attached Images

04-03-2006, 08:44 PM	#9
grega57 Registered User Join Date: Apr 2006 Location: Kansas Posts: 11	Re: Temperature gauge sensor/'70 pickup Thanks to all of you that have responded. I've pulled the old idiot light sensor and measured the hole at 5/8" diameter. The sensor that is suppose to be the replacement part fills a threaded hole that measures 3/4". The sensor I pulled has a number on it, "HS125CM 2639". I checked with GM and they say it's not their part. I've found a sensor that will fit but it is a Ford part so I'm guessing it won't work. Greg

04-04-2006, 06:59 AM	#12
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Re: Temperature gauge sensor/'70 pickup The stock sensor is 1/2 N.P.T. threads. It sounds like you have later model heads if the hole is too small. __________________ I'm on the Instagram- @Gearhead_Kevin



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