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Possibly overheated?

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Old 06-21-2007, 04:29 PM
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Default Possibly overheated?

I drove my car around today for the 1st time in awhile in the 90 degree humid heat. My temp guage was at 210 and by the way if you run hotter do these things really go past 210? Back to my story I have 2 tranny coolers in front of the condensor but I really dont think it would cause it. Back when I had coolant issues (due to heads) i was alwasy checking my coolant level to see if it dropped after i shut it down and i removed those faulty heads month ago. Well today I got curious after driving just to check on it and it seems as there was ALOT more pressure in there and it was boiling some after i loosend the cap and put it back on. The overflow tank was at the top and spitting out when i cracked the radiator cap..but it wasnt pissing out while driving. This have never done this before when it was hot before. Do you think I almost overheated or it was just good and hot? Why wasnt there so much pressure in there before with the other heads?
Old 06-22-2007, 01:41 AM
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First, did your old heads have a coolant leak for sure? that would bleed the nessassary pressure for the coolant system. typical coolant sytems need around 15psi to keep the boiling of the coolant/water up. Before you pulled the cap off to find it boiling what was the gauge relativaly reading? Remember the boiling point of the coolant/ water is higher when under pressure. when you took off the cap the pressure was reduced to atmospheric pressure (down from the normal 15psig) and the boiling point was instantly lowered, hence the reason it suddendly started to boil.
FWIW, if you put a glass of water in a vacuum it will boil at room temps! the boiling point differences between 14.7 psi(sea level average) and 0psi (vacuum) is 212* and room temp averages respectivly. i dont remember the #'s exactly. sorry for nuking it but it sounds like all is fine in that department.
Old 06-22-2007, 01:45 AM
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Originally Posted by AutomagicLS1
I drove my car around today for the 1st time in awhile in the 90 degree humid heat. My temp guage was at 210 and by the way if you run hotter do these things really go past 210? Back to my story I have 2 tranny coolers in front of the condensor but I really dont think it would cause it. Back when I had coolant issues (due to heads) i was alwasy checking my coolant level to see if it dropped after i shut it down and i removed those faulty heads month ago. Well today I got curious after driving just to check on it and it seems as there was ALOT more pressure in there and it was boiling some after i loosend the cap and put it back on. The overflow tank was at the top and spitting out when i cracked the radiator cap..but it wasnt pissing out while driving. This have never done this before when it was hot before. Do you think I almost overheated or it was just good and hot? Why wasnt there so much pressure in there before with the other heads?
Oh, yeah, mine runs close to 210 but just a shy under. if i get mauch past that the fans kick on. not too uncommon for hot weather. I just replaced my thermostat after it stuck closed and red lined the temps before i could safely get off the road-around 260*.
Old 06-22-2007, 04:47 AM
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Originally Posted by lunatik
First, did your old heads have a coolant leak for sure? that would bleed the nessassary pressure for the coolant system. typical coolant sytems need around 15psi to keep the boiling of the coolant/water up. Before you pulled the cap off to find it boiling what was the gauge relativaly reading? Remember the boiling point of the coolant/ water is higher when under pressure. when you took off the cap the pressure was reduced to atmospheric pressure (down from the normal 15psig) and the boiling point was instantly lowered, hence the reason it suddendly started to boil.
FWIW, if you put a glass of water in a vacuum it will boil at room temps! the boiling point differences between 14.7 psi(sea level average) and 0psi (vacuum) is 212* and room temp averages respectivly. i dont remember the #'s exactly. sorry for nuking it but it sounds like all is fine in that department.
The previous heads did have a pinhole leak in 1 of the intake ports. It wasnt boiling when I shut the car off and the temp guage was at 210. I have NEVER seen it go past 210...will it go passed it if its going to overheat? The boiling didnt start till i cracked the cap open and there was a WHOLE lot of pressure in there...I was just concerned b/c it has never done that before pressure and boiling....I drove it again yesterday and to work last night and everything seemed kosher...the only coolant that pissed out was some that came out of the overflow reservoir when i popped the cap a little
Old 06-22-2007, 05:01 AM
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I sure your in the clear now. As above, the pressure built up in the system is needed and keeps the coolant from boiling at too low a temp when the cap is opened the pressure is released and there is nothing to keep it from boiling then. for a peace of mind you could listen to the radiator just before you would pop the cap off. use a screw driver to the ear method (you may only need to place ear near the cap to hear boiling). or use a stethiscope (i cant spell worth a crap) something like what doctors use to listen closely. you shouldnt hear any boiling at that moment. < only when the cap is opened.be carefull in this as a good friend of mine got steam blasted (overheated on he popped the rad cap off).
yeah, sometimes the temps can creep past 210 but it should be very brief depending on the outside temps and fan settings.
but again, sounds like all is normal for you. i hope this brings some peace of mind.
Old 06-22-2007, 05:08 AM
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just a little extra back ground. the pressure that keeps the coolant from boiling is important because when the coolant boils it forms steam and steam can not absorb heat like liquid can and will cause a localized hot spots that can wreck havok by over heating parts of the engine but the over all temps showing on the gauge will say all is normal. you amy already know all this but in case someone researches this subject they might find this helpfull. thanks for the patience.
+the proper pressure for the system can be 15psi or a few more resulting in that huge pressure release you mentioned.
Old 06-22-2007, 11:11 AM
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Originally Posted by lunatik
just a little extra back ground. the pressure that keeps the coolant from boiling is important because when the coolant boils it forms steam and steam can not absorb heat like liquid can and will cause a localized hot spots that can wreck havok by over heating parts of the engine but the over all temps showing on the gauge will say all is normal. you amy already know all this but in case someone researches this subject they might find this helpfull. thanks for the patience.
+the proper pressure for the system can be 15psi or a few more resulting in that huge pressure release you mentioned.
Thanks alot for all the information. It makes sense now
Old 06-22-2007, 12:21 PM
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Not a problem bro.




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