Radiator issues (maybe?) - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Spline64 · 01-06-2011, 02:05 AM

I am truly sorry if this is the wrong forum for this, Google searches aren't helping me much.

Thermostat went bad, became stuck closed, drove to work (no temp gauge so no clue and heater was not happening at all and it normally works) and when I got there steam and lost over half my coolant. crap....

Removed thermostat so I could go to auto parts store and get a new one. Replaced coolant. Ran cold to warm as expected till I got home.

Put in new thermostat, 15 deg higher rating as that was the recommended for my engine (180 old now 195). Now heater is working great, but noticed that top manifold intake hose is still cold. Could this be the fact that it just hasn't heated up enough yet? Haven't taken it for a drive yet, and noticed that where the heater core attaches and cap side of the radiator is hot while the top hose (manifold intake) is still cold.

does it just need to get hot before it opens?

thanks,
Spline64

zac · 01-06-2011, 08:11 AM

Well, wrong forum, yes, but this is easy. Your system sounds like it is working normally now. The heater core gets water from the engine block, so it warms as the engine warms. The top hose will stay cold until 195 when the thermostat opens. It seems to take forever for the thermostat to open when your truck is idling in the driveway. Drive it down the road a few miles, pull over and feel the top hose. Fix the temp gauge!

eyebuzz · 01-07-2011, 12:08 PM

You could also test that thermostat out by taking it out and putting it in pot of hot water - not quite boiling - and see if it opens up - would help of course to have thermometer that reads 195...but if nothing else it if didn't open when the water was boiling then it's not working.

Yes, get that temp gauge fixed anyway. Best, TT

Spline64 · 01-07-2011, 05:10 PM

Thanks guys, zac you were correct, the top hose got hot after driving a few miles. Heater works better then ever (probably cause the t-stat is now 15 deg higher). Engine even runs better now, guess it was never reaching optimum operating temperature.
Eyebuzz, I did put it in boiling water and it only opened up less than a 1/16". Couldn't even push it open with my thumbs beyond that. The new one would let me push it over a half inch open.
Amazing that a $4 part could ruin a $1000 engine.....getting the temp gauge this weekend. If that was working I wouldn't of almost ruined the engine

again, thanks!!
Spline64

01-06-2011, 02:05 AM	#1
Spline64 Registered User Join Date: Sep 2010 Location: Gardnerville, Nevada Posts: 68	Radiator issues (maybe?) I am truly sorry if this is the wrong forum for this, Google searches aren't helping me much. Thermostat went bad, became stuck closed, drove to work (no temp gauge so no clue and heater was not happening at all and it normally works) and when I got there steam and lost over half my coolant. crap.... Removed thermostat so I could go to auto parts store and get a new one. Replaced coolant. Ran cold to warm as expected till I got home. Put in new thermostat, 15 deg higher rating as that was the recommended for my engine (180 old now 195). Now heater is working great, but noticed that top manifold intake hose is still cold. Could this be the fact that it just hasn't heated up enough yet? Haven't taken it for a drive yet, and noticed that where the heater core attaches and cap side of the radiator is hot while the top hose (manifold intake) is still cold. does it just need to get hot before it opens? thanks, Spline64

01-06-2011, 08:11 AM	#2
zac Registered User Join Date: Jul 2008 Location: louisville, ky Posts: 502	Re: Radiator issues (maybe?) Well, wrong forum, yes, but this is easy. Your system sounds like it is working normally now. The heater core gets water from the engine block, so it warms as the engine warms. The top hose will stay cold until 195 when the thermostat opens. It seems to take forever for the thermostat to open when your truck is idling in the driveway. Drive it down the road a few miles, pull over and feel the top hose. Fix the temp gauge!

01-07-2011, 12:08 PM	#3
eyebuzz Licensed driver Join Date: Jun 2010 Location: Tarrytown, NY Posts: 161	Re: Radiator issues (maybe?) You could also test that thermostat out by taking it out and putting it in pot of hot water - not quite boiling - and see if it opens up - would help of course to have thermometer that reads 195...but if nothing else it if didn't open when the water was boiling then it's not working. Yes, get that temp gauge fixed anyway. Best, TT

01-07-2011, 05:10 PM	#4
Spline64 Registered User Join Date: Sep 2010 Location: Gardnerville, Nevada Posts: 68	Re: Radiator issues (maybe?) Thanks guys, zac you were correct, the top hose got hot after driving a few miles. Heater works better then ever (probably cause the t-stat is now 15 deg higher). Engine even runs better now, guess it was never reaching optimum operating temperature. Eyebuzz, I did put it in boiling water and it only opened up less than a 1/16". Couldn't even push it open with my thumbs beyond that. The new one would let me push it over a half inch open. Amazing that a $4 part could ruin a $1000 engine.....getting the temp gauge this weekend. If that was working I wouldn't of almost ruined the engine again, thanks!! Spline64



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