overheating. i hate gm!
07-26-2005, 11:17 PM
#1
overheating. i hate gm! damn you gm! every damn car other then mine has a fan that stays on after i shut off the car to prevent the engine from getting too hot. wouldnt it make sense to put it on a big engine like a LS1? i just took my car for a ride, turned it off and i went to turn it back on about 3 or 4 minutes later, the damn motor wouldnt start and the temp gauge was almost at the red. i tried it again a minute later and it started, barely. is there anyway i can prevent this again? it really troubles me to let my car get so hot after i turn it off. i know if it gets too hot after i turn it off that something can crack. thanks in advance
jacob
jacob
07-26-2005, 11:36 PM
#2
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once your car is shut off...the temp should go down...because the hot *** explosions going on inside the engine have stopped. also..once the car is off...even if the rad fan is still on or not...the coolant isn't flowing through it anymore because the water pump isn't running. so you have a different problem...was the car overheating before you shut it off? alos...so cars have hot start problems.
07-27-2005, 08:59 AM
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If your fans were programmed to maintain a sensible
coolant temp, you would not see the engine rise up
to the cutoff temp when sitting after shutdown.
If I recall there is the ability to after-run the fans
though it is not enabled from factory. Personally I
don't see much value in it and find it annoying.
Not sure whether thermosiphon cooling is going to
do much for you, fans on or no.
But a proper block temp to begin with, will help.
coolant temp, you would not see the engine rise up
to the cutoff temp when sitting after shutdown.
If I recall there is the ability to after-run the fans
though it is not enabled from factory. Personally I
don't see much value in it and find it annoying.
Not sure whether thermosiphon cooling is going to
do much for you, fans on or no.
But a proper block temp to begin with, will help.
07-27-2005, 09:06 AM
#5
the car can keep a the temp around 210 while i'm driving, it creeps up while i get on it sometimes. but after i shut it off it'll go all the way up... and if i restart it shortly after, the temperature is usually almost at the red zone. once the thermostat kicks in and such the temperature goes down pretty quickly, it just scares me to see it that high to begin with
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07-27-2005, 09:27 AM
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Something must be wrong. Shortly after I bought my car (used), I noticed that the coolant temp was almost hitting the RED marker. I also noticed that the fans would stay on for a few minutes after turning the car off. I quickly replaced the T-stat with a 160* and haven't had that happen since.
07-27-2005, 09:51 AM
#11
i would hook up a scan tool and check the temp through the computer to make sure your gauge is reading correctly. If the gauge is reading right, change the thermostat. A coolant flush probably wouldn't hurt either, but I would not put dexcool back in. I would use green antifreeze.
07-27-2005, 11:54 AM
#12
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Hi Folks
If the engine would not turn over it was hot regardless what the scan tool or the temperature gauge indicates - it is HOT! I can tell about 97 LT1 (my 02 SS never gets that hot), if the temperature of the engine is hot (a little past center) and I shut it down, the fans will stay on - I have never seen them come on after I shut it down but I have never looked.
The issue about the engine getting hotter after you shut it down, well first, the engine is continuously being cooled when it is running and heat is being pulled out the block. The block itself is very hot and has mass to it. Yes when it is shut down the cooling action stops and the temperature will rise while it is sitting there - it is physics
Thanks
Bill
If the engine would not turn over it was hot regardless what the scan tool or the temperature gauge indicates - it is HOT! I can tell about 97 LT1 (my 02 SS never gets that hot), if the temperature of the engine is hot (a little past center) and I shut it down, the fans will stay on - I have never seen them come on after I shut it down but I have never looked.
The issue about the engine getting hotter after you shut it down, well first, the engine is continuously being cooled when it is running and heat is being pulled out the block. The block itself is very hot and has mass to it. Yes when it is shut down the cooling action stops and the temperature will rise while it is sitting there - it is physics
Thanks
Bill
07-27-2005, 12:05 PM
#13
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The reason temps go up is, the heat removal lags
the heat generated in the chamber. You achieve
steady state temperature at the water jacket by
thermostat action (fluid, or fans via the PCM's
half-assed thermostatic control). But stop the
coolant flow and all of the heat held in the head
metal, now has nowhere to go, just heat dump into
the stagnant coolant nearby (where also lies the
ECT sensor). The thermal profile will slump and
the higher temps at the cylinder wall and the lower
coolant temp will come to the same value, in the
middle somewhere.
If your water jacket was 30 degrees cooler to
begin with, that would shave a fair bit off the
"average". And if you are forming steam pockets
from the sudden stagnation, then the temp will
"share" in a very different, worse proportion as
steam doesn't cool for ****.
the heat generated in the chamber. You achieve
steady state temperature at the water jacket by
thermostat action (fluid, or fans via the PCM's
half-assed thermostatic control). But stop the
coolant flow and all of the heat held in the head
metal, now has nowhere to go, just heat dump into
the stagnant coolant nearby (where also lies the
ECT sensor). The thermal profile will slump and
the higher temps at the cylinder wall and the lower
coolant temp will come to the same value, in the
middle somewhere.
If your water jacket was 30 degrees cooler to
begin with, that would shave a fair bit off the
"average". And if you are forming steam pockets
from the sudden stagnation, then the temp will
"share" in a very different, worse proportion as
steam doesn't cool for ****.
07-27-2005, 12:16 PM
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An engine will always go up in temp as soon as you turn it off. The coolant stops flowing to cool so where is the heat going to go, nowhere There is no coolant to carry it away. There fore an engine will always go up in temp when it is cut off and will take 5 to 10 minutes to cool back down to the operating temp.. The no start sounds like a completley diff. prob.
07-27-2005, 06:08 PM
#16
now what doesnt make sense is that it only happens to me? i took the car to the dealer when i first noticed the problem and they said that it was normal and that if it stays below the red during normal operationg conditions that it was fine. but my car didnt start yesterday! and my fan doesnt stay on after i turn off my car like all yours. i understand what Bill said and that makes a ton of sense to me, what i dont understand is, what could possibly be done to keep an engine cool after i shut off the car?
07-27-2005, 06:16 PM
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Originally Posted by qwikz28
now what doesnt make sense is that it only happens to me? i took the car to the dealer when i first noticed the problem and they said that it was normal and that if it stays below the red during normal operationg conditions that it was fine. but my car didnt start yesterday! and my fan doesnt stay on after i turn off my car like all yours. i understand what Bill said and that makes a ton of sense to me, what i dont understand is, what could possibly be done to keep an engine cool after i shut off the car?
07-27-2005, 06:34 PM
#18
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hey, check your coolant level, low coolant will cause over heating. normal operating temp shouldnt be at 210 or above, think your termostat is sticking closed. Easy to check if it opens at the right temp. feel the upper radiator hose-going into thermostat when thermostat opens it gets hot. when the operating temp reaches 190 feel th hose, should be hot. if it opens after 190 degrees bad thermostat.
07-28-2005, 09:33 AM
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Sounds to me like an air bubble or a bad t-stat (not opening) causing steam in the passenger side head. After you turn it off the coolant stops flowing and if there is not alot of coolant in the heads it will steam up and raise the temperature in the heads.
Try pulling the T-stat and see what happens. Also jack up the front of the car as high as it will go and run the car at a fast idle with the radiator cap off. That should force out any air bubbles.
Try pulling the T-stat and see what happens. Also jack up the front of the car as high as it will go and run the car at a fast idle with the radiator cap off. That should force out any air bubbles.