wierd thermostat thing
Thread Starter
Le Mans Master
Joined: Jun 2008
Posts: 5,284
Likes: 235
From: Rockledge FL
wierd thermostat thing
what is causing this, i put in a new thermostat after flushing my cooling system. i tested the tstat in boiling water and a candy thermometer and it opend up just at the temp it is supposed to.
i get finished with the flush and install the thermostat.
after 10 mins the car is overheating. the upper radiator hose is rock hard.
i let it cool down and unbolt the tstat housing and put it all back together without the thermostat this time and the coolant temp barely got over 210.
i retested the thermostat in boiling water and it opened up again.
strange. i am going to replace it with one of those fail safe models i guess but id like to know what might have been causing it not to open when installed.
i get finished with the flush and install the thermostat.
after 10 mins the car is overheating. the upper radiator hose is rock hard.
i let it cool down and unbolt the tstat housing and put it all back together without the thermostat this time and the coolant temp barely got over 210.
i retested the thermostat in boiling water and it opened up again.
strange. i am going to replace it with one of those fail safe models i guess but id like to know what might have been causing it not to open when installed.
Drifting
Joined: Aug 2008
Posts: 1,381
Likes: 11
If the t-stat was installed correctly (the point will "point" towards the radiator and the spring will point down) the only other problem you could have caused is an air bubble or air lock, which is rare with a vette because the top of the radiator sits below the t-stat. A sure fire way to prevent the air lock is to drill a small hole (1/8" or so ) in the flange of the t-stat. If you are adversed to drilling the bleed hole, install the t-stat, fill the radiator to 4" below the top, start and run the engine at 1,000 rpm. Now look in the radiator with a flashlight, as the temp rises to the t-stat opening temp you should start to see coolant flow from the upper tubes in the radiator. Also, most t-stats won't start to open until they are at or past the rated temp, and they won't be fully open until 10 or 15 degrees beyond the rated temp - you probably noticed this when you tested it with the candy thermometer.
Thread Starter
Le Mans Master
Joined: Jun 2008
Posts: 5,284
Likes: 235
From: Rockledge FL
this t stat already had a bleed hole in it,
it was installed with the spring going down into the intake. the tip section is up.
i dont see how i can fill the radiator to be able to see the water line, the fill cap is on the expansion tank by the right fender. no fill hole in the radiator.
tstat was rated at 195 the gauge pegged the needle. even if it didnt fully open until 10 or so past it shouldnt peg the needle at idle in 10 minutes with the factory rated tstat.
it was installed with the spring going down into the intake. the tip section is up.
i dont see how i can fill the radiator to be able to see the water line, the fill cap is on the expansion tank by the right fender. no fill hole in the radiator.
tstat was rated at 195 the gauge pegged the needle. even if it didnt fully open until 10 or so past it shouldnt peg the needle at idle in 10 minutes with the factory rated tstat.
Thread Starter
Le Mans Master
Joined: Jun 2008
Posts: 5,284
Likes: 235
From: Rockledge FL
when its over 100 outside it idles in traffic around 225 but goes back to 210 when moving.
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Thread Starter
Le Mans Master
Joined: Jun 2008
Posts: 5,284
Likes: 235
From: Rockledge FL
Melting Slicks
Joined: Oct 2002
Posts: 2,317
Likes: 111
From: St Louis MO
Sounds like it is time to replace your temp sensor - at idle, your coolant temp should be quite close to the thermostat value.
As far as the upper hose becoming hard, this is normal as the water pressure increases as the coolant warms up. The upper pressure is limited by the radiator cap which opens to let the expanding coolant into the coolant recovery tank.
As far as the upper hose becoming hard, this is normal as the water pressure increases as the coolant warms up. The upper pressure is limited by the radiator cap which opens to let the expanding coolant into the coolant recovery tank.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Hmmm Well that should insure the water pump is full but I actually start my fill through the plug in the top of the pump (because I'm a bit ****).With the hole in the thermostat you should have flow.Not saying 210 is great but not knowing what your outside temp is and how accurate your gauge is 210 minus the therm. doesnt bring up "huge" red flags. After running minus the thermostat did you redrain the system to reinstall the thermostat or just remove the housing and reinstall ?
Thread Starter
Le Mans Master
Joined: Jun 2008
Posts: 5,284
Likes: 235
From: Rockledge FL
Melting Slicks
Joined: Dec 2000
Posts: 3,407
Likes: 2
From: Carmichael CA
Also, as pointed out...the temperature gauge should be reading about 160º at idle without a thermostat if the coolant system was doing it's job. So, it sounds like either your temperature gauge and/or sensor are not compatible or are malfunctioning, and/or something else in the system is not doing it's job such as water pump may not be spinning fast enough i.e. someone put in a larger pump pulley, plugged lines in the radiator core, or perhaps the problem is insufficient air flow through the radiator i.e. fan not turning fast enough, fan too small, missing shroud, etc.
But, if the problem is air flow then the temp should drop while driving above 40mph...as long as you still have the air dam. If this is not the case, then the most probable reason is plugged lines in the radiator core which requires removing the radiator and giving it a nice hot acid bath.
Drifting
Joined: Aug 2008
Posts: 1,381
Likes: 11
Here's the thing - IF the t-stat was the ONLY thing changed, then that is the problem. And if the temp gauge reading was fine before, that just confirms it. Put the old stat back in and check it. I can tell you I have experienced similar things with the Mr. Gasket high flow stat (the goofy looking one with the long spring on it). Switching back to the original functioning part will solve your puzzle.