Possible T-stat problem. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

WarBeard · 10-09-2011, 10:40 PM

The truck: 1974 with a 350 2bbl all stock.

OK So I just replaced the failed fan clutch and water pump, The problem now is when its running I don't feel the upper water hose getting hot. The lower hose is slightly warmer and the heater hoses are hot like the sun! The heater in the cab works awesome LOL.

SO my question is....Bad T-stat or clogged Radiator?

My water temp gauge doesn't move and I just bought the truck so I don't know if it works or not.

WarBeard · 10-09-2011, 10:43 PM

I just boiled the stat and it opened and closed like normal. I don't have a temp gauge so who knows if it is opening at the right temp.

It's a 195 degree stat..took it up to a rolling boil and it opened and when removed from the water it closed like it should.

85Bowtie · 10-09-2011, 11:20 PM

What's the longest you've driven the truck? I drove my Charger ~20 miles this afternoon and when I stopped the upper hose still wasn't "hot" and pressurized like it normally is in the summer after 20 miles of driving. Did you pop the radiator cap with the truck warmed up and see water flowing?

WarBeard · 10-09-2011, 11:27 PM

Yeah it's got one of those radiator caps with the little lever on it to relieve pressure. I lifted the lever and some water was shot into the overflow bottle.

I wonder if I just did not let it heat up enough (It was only 60 degrees out today) The heater hoses coming from the intake manifold were very hot to the touch but everything else was not hot at all?

I may of screwed up by not letting it get hot and pulling the stat. I haven't driven it at all except for driving it home because it needed a water pump and the fan clutch was about to fall off.

Tomorrow I will re-install the stat and gasket and just let it run for a while.

Rogue_Alphonse · 10-10-2011, 12:45 AM

Bad rad cap maybe?

texastruckjunky · 10-10-2011, 01:52 AM

Try it with out the stat see what happens, if it still the same i would say it was the radiator.

WarBeard · 10-10-2011, 04:46 PM

So since it was out, I went and bought a new stat and gasket and installed it (Just waiting for the RTV to dry)

I covered the end of the top radiator hose with a rag and Blew air into it with my mouth and held my hand on the fill hole and air was coming out. The inside of the rad looks very clean actually now that I can see it in the daylight so I dont think its plugged up.

So we will see how this works!

WarBeard · 10-10-2011, 07:37 PM

IT'S ALIVE!!!!!!!!!!!...MUST HAVE BEEN A BAD T-STAT!!!!!

Runs ok..Seems like a lot of noise from under the valve covers (Ticking)

Oh And I think I have a locker in the back I have two black patches of rubber behind me!

10-09-2011, 10:40 PM	#1
WarBeard Registered User Join Date: Jul 2008 Location: Show low,az Posts: 808	Possible T-stat problem. The truck: 1974 with a 350 2bbl all stock. OK So I just replaced the failed fan clutch and water pump, The problem now is when its running I don't feel the upper water hose getting hot. The lower hose is slightly warmer and the heater hoses are hot like the sun! The heater in the cab works awesome LOL. SO my question is....Bad T-stat or clogged Radiator? My water temp gauge doesn't move and I just bought the truck so I don't know if it works or not. __________________ 1978 C10 Silverado Big 10 350/350.. play toy 1990 V1500 Suburban 350/700r4..Daily driver 1987 K10 Silverado 383/400.. Wife's rig WRECKED! 1989 V2500 Suburban 350/400.. SOLD! 1974 C10 Custom10 LWB 350/350.. SOLD! 1974 C10 Custom10 SWB 350/400.. SOLD! 1999 Silverado Z71 LS1.. Wife's rig WRECKED! On the hunt for a new project....... I'm a Chevy guy.....I'm just not a "NEW" Chevy guy.

10-09-2011, 10:43 PM	#2
WarBeard Registered User Join Date: Jul 2008 Location: Show low,az Posts: 808	Re: Possible T-stat problem. I just boiled the stat and it opened and closed like normal. I don't have a temp gauge so who knows if it is opening at the right temp. It's a 195 degree stat..took it up to a rolling boil and it opened and when removed from the water it closed like it should. __________________ 1978 C10 Silverado Big 10 350/350.. play toy 1990 V1500 Suburban 350/700r4..Daily driver 1987 K10 Silverado 383/400.. Wife's rig WRECKED! 1989 V2500 Suburban 350/400.. SOLD! 1974 C10 Custom10 LWB 350/350.. SOLD! 1974 C10 Custom10 SWB 350/400.. SOLD! 1999 Silverado Z71 LS1.. Wife's rig WRECKED! On the hunt for a new project....... I'm a Chevy guy.....I'm just not a "NEW" Chevy guy.

10-09-2011, 11:20 PM	#3
85Bowtie Registered User Join Date: Mar 2009 Location: TN Posts: 410	Re: Possible T-stat problem. What's the longest you've driven the truck? I drove my Charger ~20 miles this afternoon and when I stopped the upper hose still wasn't "hot" and pressurized like it normally is in the summer after 20 miles of driving. Did you pop the radiator cap with the truck warmed up and see water flowing? __________________ '69 Dodge Charger R/T 440, 727, 3.55 Sure Grip '68 Plymouth Road Runner 383, 727, 3.23 Sure Grip '89 Dodge Diplomat ex cop car 408, 727, 3.55 Sure Grip '77 Dodge Monaco ex cop car 440, 727, 2.71 '79 Dodge 'Lil Red Express pickup 360, 727, 3.55 Sure Grip '12 Dodge Challenger SRT8 392, M6, 3.92 '85 Chevrolet C-10 SWB 2wd 305, TH350, 2.73

10-09-2011, 11:27 PM	#4
WarBeard Registered User Join Date: Jul 2008 Location: Show low,az Posts: 808	Re: Possible T-stat problem. Yeah it's got one of those radiator caps with the little lever on it to relieve pressure. I lifted the lever and some water was shot into the overflow bottle. I wonder if I just did not let it heat up enough (It was only 60 degrees out today) The heater hoses coming from the intake manifold were very hot to the touch but everything else was not hot at all? I may of screwed up by not letting it get hot and pulling the stat. I haven't driven it at all except for driving it home because it needed a water pump and the fan clutch was about to fall off. Tomorrow I will re-install the stat and gasket and just let it run for a while. __________________ 1978 C10 Silverado Big 10 350/350.. play toy 1990 V1500 Suburban 350/700r4..Daily driver 1987 K10 Silverado 383/400.. Wife's rig WRECKED! 1989 V2500 Suburban 350/400.. SOLD! 1974 C10 Custom10 LWB 350/350.. SOLD! 1974 C10 Custom10 SWB 350/400.. SOLD! 1999 Silverado Z71 LS1.. Wife's rig WRECKED! On the hunt for a new project....... I'm a Chevy guy.....I'm just not a "NEW" Chevy guy.

10-10-2011, 12:45 AM	#5
Rogue_Alphonse Registered User Join Date: Dec 2009 Location: Gap PA Posts: 280	Re: Possible T-stat problem. Bad rad cap maybe? __________________ 1991 Mustang GT Vert, T-5 w/ Pro 5.0, Trick Flow upper & lower, BBK cold air intake, 3:73, BAMA chip, etc. 1988 K5 Blazer, [coming soon] TBI 400, SM465/NP208, 12 bolt rear, 3:08's, looks like a 1980. 1998 Jeep Grand Cherokee 4.0 fully loaded daily driver! Where there's a will, there's a rig!

10-10-2011, 01:52 AM	#6
texastruckjunky Registered User Join Date: May 2009 Location: San Antonio,Texas Posts: 220	Re: Possible T-stat problem. Try it with out the stat see what happens, if it still the same i would say it was the radiator.

10-10-2011, 04:46 PM	#7
WarBeard Registered User Join Date: Jul 2008 Location: Show low,az Posts: 808	Re: Possible T-stat problem. So since it was out, I went and bought a new stat and gasket and installed it (Just waiting for the RTV to dry) I covered the end of the top radiator hose with a rag and Blew air into it with my mouth and held my hand on the fill hole and air was coming out. The inside of the rad looks very clean actually now that I can see it in the daylight so I dont think its plugged up. So we will see how this works! __________________ 1978 C10 Silverado Big 10 350/350.. play toy 1990 V1500 Suburban 350/700r4..Daily driver 1987 K10 Silverado 383/400.. Wife's rig WRECKED! 1989 V2500 Suburban 350/400.. SOLD! 1974 C10 Custom10 LWB 350/350.. SOLD! 1974 C10 Custom10 SWB 350/400.. SOLD! 1999 Silverado Z71 LS1.. Wife's rig WRECKED! On the hunt for a new project....... I'm a Chevy guy.....I'm just not a "NEW" Chevy guy.

10-10-2011, 07:37 PM	#8
WarBeard Registered User Join Date: Jul 2008 Location: Show low,az Posts: 808	Re: Possible T-stat problem. IT'S ALIVE!!!!!!!!!!!...MUST HAVE BEEN A BAD T-STAT!!!!! Runs ok..Seems like a lot of noise from under the valve covers (Ticking) Oh And I think I have a locker in the back I have two black patches of rubber behind me! __________________ 1978 C10 Silverado Big 10 350/350.. play toy 1990 V1500 Suburban 350/700r4..Daily driver 1987 K10 Silverado 383/400.. Wife's rig WRECKED! 1989 V2500 Suburban 350/400.. SOLD! 1974 C10 Custom10 LWB 350/350.. SOLD! 1974 C10 Custom10 SWB 350/400.. SOLD! 1999 Silverado Z71 LS1.. Wife's rig WRECKED! On the hunt for a new project....... I'm a Chevy guy.....I'm just not a "NEW" Chevy guy.



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