Position of stock temp guage - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Red68 · 11-14-2004, 01:23 PM

I recently rewired my entire truck with the painless kit. It works great however, I have a question, prior to rewiring my truck the stock temp guage did not work (maybe because of the wiring or printed circuit panel) so I had an after market guage.

Now after my the engine warms up the temp guage sits at the 1st line and sometimes creaps up to the "orange" area. Is this normal? I checked the temp of several places on the engine block with a laser temp sensor and it ranged between 180 and 200. I did not have a overheating problem prior to rewiring the truck.

Thanks for any advice.

Longhorn Man · 11-14-2004, 03:51 PM

A few possabilities here, the first sounding like you have a 160 - 180 degree t-stat. The guage works off a graduated scale, and will not read quite right with the cooler t-stat. (designed for a 195 stat) I know these numbers don't seem like much, but on a graduated scale, it could be quite a bit.
Is there thread tape on your sending unit? Sometimes the tape can hinder the grounding effect, and cause a low reading. Since it is a pipe thread fitting, no sealant is needed.
You may well just have a bum guage.

**Stocker** · 11-14-2004, 07:18 PM

My factory gauge reads well below halfway, more like about 1/3 from the left when at full operating temp.

71-longbed · 11-14-2004, 10:04 PM

mine sits a 1/4 inch above the small line at operating temp

dinnut · 11-14-2004, 10:50 PM

and before i swapped out my intake, carb and t-stat my gauge would never read about 1/2 on the gauge now it reads like its burning up all the time... i guess its my gauge or its the t-stat throwing it off...

Longhorn Man · 11-15-2004, 12:09 AM

burning all the time? you mean it is pegged out as soon as you turn on the ignition?
If so, trace the green wire from the sending unit in the head to the harness bulhead. Odds are, it is grounded out somewhere...like melted to an exhaust manifold/header.

Red68 · 11-15-2004, 06:04 PM

Longhorn Man, thanks for the reply, I do not recall what temp my thermostat is I thought is was 190, could be wrong. I started out with teflon tape on the threads, after a conversation with a mech friend I fixed that. Still the same. I hate to buy a new temp guage not knowing if the one I have is bad. Is there any way to check the guage?

Longhorn Man · 11-15-2004, 07:10 PM

If you could measure the resistance at certian temperatures, knowing what OHM reading should translate into what reading on teh guage, then you could find out how acurate your guage really is.
Personally, I'd hunt down a used temp guage before doing all that jive. (in reality, since I don't trust 35 yr old guages, I'd replace them all with aftermarket...like I have on both my trucks)

11-14-2004, 01:23 PM	#1
Red68 Registered User Join Date: Jan 2002 Location: Rhome, TX Posts: 209	Position of stock temp guage I recently rewired my entire truck with the painless kit. It works great however, I have a question, prior to rewiring my truck the stock temp guage did not work (maybe because of the wiring or printed circuit panel) so I had an after market guage. Now after my the engine warms up the temp guage sits at the 1st line and sometimes creaps up to the "orange" area. Is this normal? I checked the temp of several places on the engine block with a laser temp sensor and it ranged between 180 and 200. I did not have a overheating problem prior to rewiring the truck. Thanks for any advice. __________________ 1968 C10 LWB 327 bored 40 over, RHS heads, KB pistons, Eagle rods, Edlebrock carb & intake 1968 C10 flatbed 307 w/ 4 spd manual (dads old ride) 1936 1/2 tn pickup, 400sb 350 turbo (partially restored) 1949 1/2 tn, needs complete restore (future project) 1969 Chevy impala 4 dr no post (wifes future car) 2010 GMC Serria 4x4 crew, leveling kit

11-14-2004, 03:51 PM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	A few possabilities here, the first sounding like you have a 160 - 180 degree t-stat. The guage works off a graduated scale, and will not read quite right with the cooler t-stat. (designed for a 195 stat) I know these numbers don't seem like much, but on a graduated scale, it could be quite a bit. Is there thread tape on your sending unit? Sometimes the tape can hinder the grounding effect, and cause a low reading. Since it is a pipe thread fitting, no sealant is needed. You may well just have a bum guage. Last edited by Longhorn Man; 11-15-2004 at 07:10 PM.

11-14-2004, 07:18 PM	#3
Stocker 20' Daredevil (Ret) Join Date: May 2003 Location: Jefferson State Posts: 13,722	My factory gauge reads well below halfway, more like about 1/3 from the left when at full operating temp. __________________ - Mike - 1972 K20 LWB 350/350/205 RIP El Jay

11-14-2004, 10:04 PM	#4
71-longbed Its Magically Delicious Join Date: Jan 2003 Location: oregon Posts: 2,398	mine sits a 1/4 inch above the small line at operating temp __________________ 71 C10 LWB 350sbc -TH350 12 bolt 3.42 Posi Of all my favorite things to do, The utmost is to have a brew. My love grows for my foamy friend, with each thirst-quenching elbow bend. Beer so frosty, smooth, and cold it's paradise pure liquid gold. Yes beer means many things to me that's all for now cus I gotta pee.

11-14-2004, 10:50 PM	#5
dinnut Registered User Join Date: Apr 2003 Location: missouri city, tx Posts: 4,486	and before i swapped out my intake, carb and t-stat my gauge would never read about 1/2 on the gauge now it reads like its burning up all the time... i guess its my gauge or its the t-stat throwing it off... __________________ 70 longbed 496/th400/Ford 9"

11-15-2004, 12:09 AM	#6
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	burning all the time? you mean it is pegged out as soon as you turn on the ignition? If so, trace the green wire from the sending unit in the head to the harness bulhead. Odds are, it is grounded out somewhere...like melted to an exhaust manifold/header.

11-15-2004, 06:04 PM	#7
Red68 Registered User Join Date: Jan 2002 Location: Rhome, TX Posts: 209	Longhorn Man, thanks for the reply, I do not recall what temp my thermostat is I thought is was 190, could be wrong. I started out with teflon tape on the threads, after a conversation with a mech friend I fixed that. Still the same. I hate to buy a new temp guage not knowing if the one I have is bad. Is there any way to check the guage? __________________ 1968 C10 LWB 327 bored 40 over, RHS heads, KB pistons, Eagle rods, Edlebrock carb & intake 1968 C10 flatbed 307 w/ 4 spd manual (dads old ride) 1936 1/2 tn pickup, 400sb 350 turbo (partially restored) 1949 1/2 tn, needs complete restore (future project) 1969 Chevy impala 4 dr no post (wifes future car) 2010 GMC Serria 4x4 crew, leveling kit

11-15-2004, 07:10 PM	#8
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	If you could measure the resistance at certian temperatures, knowing what OHM reading should translate into what reading on teh guage, then you could find out how acurate your guage really is. Personally, I'd hunt down a used temp guage before doing all that jive. (in reality, since I don't trust 35 yr old guages, I'd replace them all with aftermarket...like I have on both my trucks)



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