Fired up my 400sbc - Question about temp gauge - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**Yukon Jack** · 03-19-2007, 02:41 PM

Fired up my 70 K5's rebuilt 400 sbc for the first time this weekend!

Here is an audio clip of the motor MP3 file

Here's a pic of the motor

Ran great but the temp gauge showed it was running a bit on the hot side. I'm pretty sure the gauge is not accurate - I bought the K5 and it hasn't been running since I bought it.

I have a spare bezel and was wondering if I could run a wire from the sending unit to this spare, uninstalled bezel to see what it shows for the temperature? I looked at back of the bezel and there are four posts - could I attach the wire to the correct post and get a reading - if so, anyone know which post should be used?

I did pick up a generic O'Reilly's temp gauge and hooked it to the sending unit but it didn't work - I'm guessing the generic temp gauge's sending unit must be different than the GM sending unit I have installed.

breeh · 03-19-2007, 02:54 PM

Remember that on a freshly rebuilt motor, it will run a bit warm at first while the final "machining" is taking place.

BigSky71 · 03-19-2007, 02:58 PM

Quote:

Originally Posted by Yukon Jack

Fired up my 70 K5's rebuilt 400 sbc for the first time this weekend!

I have a spare bezel and was wondering if I could run a wire from the sending unit to this spare, uninstalled bezel to see what it shows for the temperature? I looked at back of the bezel and there are four posts - could I attach the wire to the correct post and get a reading - if so, anyone know which post should be used?

I did pick up a generic O'Reilly's temp gauge and hooked it to the sending unit but it didn't work - I'm guessing the generic temp gauge's sending unit must be different than the GM sending unit I have installed.

I think you could make one of those gauges outside the bezel work, its possible you might have to ground the unit to make it work correctly.

**Palf70Step** · 03-19-2007, 03:58 PM

Best bet is get a mechanical temp gauge and hook it up and run it to see it is really hot or not. Why take the chance on a new motor.

03-19-2007, 02:41 PM	#1
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,689	Fired up my 400sbc - Question about temp gauge Fired up my 70 K5's rebuilt 400 sbc for the first time this weekend! Here is an audio clip of the motor MP3 file Here's a pic of the motor Ran great but the temp gauge showed it was running a bit on the hot side. I'm pretty sure the gauge is not accurate - I bought the K5 and it hasn't been running since I bought it. I have a spare bezel and was wondering if I could run a wire from the sending unit to this spare, uninstalled bezel to see what it shows for the temperature? I looked at back of the bezel and there are four posts - could I attach the wire to the correct post and get a reading - if so, anyone know which post should be used? I did pick up a generic O'Reilly's temp gauge and hooked it to the sending unit but it didn't work - I'm guessing the generic temp gauge's sending unit must be different than the GM sending unit I have installed. __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14 Last edited by Yukon Jack; 06-24-2010 at 11:56 AM.

03-19-2007, 02:54 PM	#2
breeh Recovering 67-72 Addict Join Date: Oct 2000 Location: North Bend, WA Posts: 1,788	Re: Fired up my 400sbc - Question about temp gauge Remember that on a freshly rebuilt motor, it will run a bit warm at first while the final "machining" is taking place. __________________ 68 Short Fleet 4x4; 427; BTO Level 3 700R4; NP205; Dana 60 front and rear; 4" lift with 35's; Disc brakes; AGR variable ratio steering; factory bucket seats; factory tach and tilt. "Friends call me cruzer cuz I like fast cars and fast women"

03-19-2007, 03:58 PM	#4
Palf70Step State of Confusion! Join Date: Jul 2002 Location: Gulfport, MS USA Posts: 47,471	Re: Fired up my 400sbc - Question about temp gauge Best bet is get a mechanical temp gauge and hook it up and run it to see it is really hot or not. Why take the chance on a new motor. __________________ Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God!



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