73-87chevytrucks.com

73-87 Chevy _ GMC Trucks => Interior & Equipment => Topic started by: 79K20 on March 30, 2009, 11:21:47 am

Title: Temperature Guage Q's
Post by: 79K20 on March 30, 2009, 11:21:47 am
Hey all.

Just trying to diagnose why my temp gauge quit working. Its a '79 K20 w/ 350 eng. I believe it is a vacuum-type temp sensor, right?

Anybody know how these things work? Is there an easy way to test the sensor and the gauge separately to see which is malfunctioning?

Thanks.
Title: Re: Temperature Guage Q's
Post by: VileZambonie on March 30, 2009, 01:36:24 pm
No, it's a thermistor. Take the wire off of the sending unit screwed into the drivers side head and ground it with the key on. See if the gauge moves.
Title: Re: Temperature Guage Q's
Post by: 79K20 on March 30, 2009, 03:15:35 pm
I thought the sending unit was on the thermostat housing...?

That blue thing with the four vacuum lines coming out of it...?
Title: Re: Temperature Guage Q's
Post by: JRConnieK10 on March 30, 2009, 03:27:09 pm
Should be on the left side head behind the first spark plug
Title: Re: Temperature Guage Q's
Post by: VileZambonie on March 30, 2009, 05:19:19 pm
That's just a thermostatic vacuum switching valve.
Title: Re: Temperature Guage Q's
Post by: 79K20 on March 31, 2009, 08:23:25 am
A What-Ditty-What? Here it comes... What on Earth does a Thermostatic Vacuum Switching Valve do?

Haven't had a chance to ground that sensor wire out. Will do it later today and see if the gauge works....
Title: Re: Temperature Guage Q's
Post by: Captkaos on March 31, 2009, 02:03:52 pm
When temp goes up it allows vaccum to pass through.