Thermostat - The 1947 - Present Chevrolet & GMC Truck Message Board Network

alf1096 · 10-15-2005, 12:10 PM

I bought the truck about 1 month ago. When it started getting cooler here I noticed that the engine would not heat up so I ordered a new therm housing and stat. I put both of them on and the truck now heats up to about 200 and the the temp gauge goes from 200 to 240 in about 3 sec and then the truck cools down from 240 to 190 in about 5 sec. I thought that may be I got a bad therm so I changed it again with another new one. It still does it but not a often with the new one. Has anyone else had this problem if so what is the fix. And will the spike to 240 for a few seconds hurt the engine any help will be great.

thanks

kelsfine69 · 10-15-2005, 12:28 PM

You might have another bad stat. anything is possible. Try a differnt brand. Also check your gage and wiring. M2C

dyingdeadman · 10-16-2005, 04:39 AM

i would check to make sure your gage is working. i thought i had a problem with overheating last week but after checking everything else i replaced the gauge. turns out the gauge had a short in it.

alf1096 · 10-16-2005, 09:30 AM

The gauge seemd to work fine before I installed the stat....There is no wiring problem it's a mechanincal gauge anyother thoughts

69 longhorn · 10-16-2005, 10:21 AM

You might have a little air trapped in the system. If you havent tryed this already, start the truck up (cold), with the rad cap off & run it till the stat opens. you will see the coolant level drop, then add to top it off & cap back on. this should get rid of any air in the system. best of luck.....69L

Longhorn Man · 10-16-2005, 10:36 AM

I was going to mention air also.
That or a bumm t-stat

LONGHAIR · 10-16-2005, 10:51 AM

The "cure" for the air bubble problem is to drill a small hole (1/8" or so) in the thermostat itself before installing it. This will allow enough flow to let any air out, while being minimal enough to have no effect on the coolant circulation.

**Stocker** · 10-16-2005, 10:58 AM

I'm also guessing air in the system - it should work itself out. And no, 240* for a few seconds won't hurt anything. It's just a momentary reading at the sensor location, not an indication of the temp throughout the engine.

alf1096 · 10-16-2005, 07:51 PM

Thanks for all or the advise I will drive it for a while and see if anything changes

thanks

alf1096 · 10-16-2005, 07:52 PM

Thanks for all or the advise I will drive it for a while and see if anything changes

thanks

10-15-2005, 12:10 PM	#1
alf1096 Registered User Join Date: Aug 2005 Location: Texas Posts: 124	Thermostat I bought the truck about 1 month ago. When it started getting cooler here I noticed that the engine would not heat up so I ordered a new therm housing and stat. I put both of them on and the truck now heats up to about 200 and the the temp gauge goes from 200 to 240 in about 3 sec and then the truck cools down from 240 to 190 in about 5 sec. I thought that may be I got a bad therm so I changed it again with another new one. It still does it but not a often with the new one. Has anyone else had this problem if so what is the fix. And will the spike to 240 for a few seconds hurt the engine any help will be great. thanks __________________ 1970 Short Stepside----Process of Restoring 1983 1/2 Silverado

10-15-2005, 12:28 PM	#2
kelsfine69 18 Till I Die Join Date: Mar 2005 Location: Alberta, Canada Posts: 1,522	You might have another bad stat. anything is possible. Try a differnt brand. Also check your gage and wiring. M2C __________________ 2011 GMC Acadia 1969 GMC BBC LS7 2007 GMC Crew Duramax 1987 Camaro Iroc 350 Tuned Port Injection 42000Km 1987 Chevrolet Silverado 350 TBI 1987 Chevrolet Silverado 350 TBI(yes 2) Take me drunk, I'm too home...

10-16-2005, 04:39 AM	#3
dyingdeadman Registered User Join Date: Aug 2004 Location: san marcos,tx Posts: 266	Re: Thermostat i would check to make sure your gage is working. i thought i had a problem with overheating last week but after checking everything else i replaced the gauge. turns out the gauge had a short in it. __________________ 72 GMC sierra 3/4 ton 402 bb 68 GMC 3/4 ton 2010 camaro rs: daily driver

10-16-2005, 09:30 AM	#4
alf1096 Registered User Join Date: Aug 2005 Location: Texas Posts: 124	Re: Thermostat The gauge seemd to work fine before I installed the stat....There is no wiring problem it's a mechanincal gauge anyother thoughts __________________ 1970 Short Stepside----Process of Restoring 1983 1/2 Silverado

10-16-2005, 10:21 AM	#5
69 longhorn Registered User Join Date: Aug 2001 Location: rock island,il,usa Posts: 5,382	Re: Thermostat You might have a little air trapped in the system. If you havent tryed this already, start the truck up (cold), with the rad cap off & run it till the stat opens. you will see the coolant level drop, then add to top it off & cap back on. this should get rid of any air in the system. best of luck.....69L __________________ http://community.webshots.com/user/hotrodhorn

10-16-2005, 10:36 AM	#6
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: Thermostat I was going to mention air also. That or a bumm t-stat

10-16-2005, 10:51 AM	#7
LONGHAIR just can't cover up my redneck Join Date: May 2004 Location: Columbus OH Posts: 11,414	Re: Thermostat The "cure" for the air bubble problem is to drill a small hole (1/8" or so) in the thermostat itself before installing it. This will allow enough flow to let any air out, while being minimal enough to have no effect on the coolant circulation.

10-16-2005, 10:58 AM	#8
Stocker 20' Daredevil (Ret) Join Date: May 2003 Location: Jefferson State Posts: 13,598	Re: Thermostat I'm also guessing air in the system - it should work itself out. And no, 240* for a few seconds won't hurt anything. It's just a momentary reading at the sensor location, not an indication of the temp throughout the engine. __________________ - Mike - 1972 K20 LWB 350/350/205 RIP El Jay

10-16-2005, 07:51 PM	#9
alf1096 Registered User Join Date: Aug 2005 Location: Texas Posts: 124	Re: Thermostat Thanks for all or the advise I will drive it for a while and see if anything changes thanks __________________ 1970 Short Stepside----Process of Restoring 1983 1/2 Silverado

10-16-2005, 07:52 PM	#10
alf1096 Registered User Join Date: Aug 2005 Location: Texas Posts: 124	Re: Thermostat Thanks for all or the advise I will drive it for a while and see if anything changes thanks __________________ 1970 Short Stepside----Process of Restoring 1983 1/2 Silverado



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