Over Heating... Help Please....
Thread Starter
Instructor
Joined: Sep 2006
Posts: 211
Likes: 0
From: Searcy Arkansas
Over Heating... Help Please....
I am having issues with my 78.(with 350) .. I just recently fired her up after a complete rebuild... I am running Flex-a-Lite 210 twin electric fans which seem to pull alot of air but the car still heats up to around the 250 mark when sitting still & does not go down when I start moving. It continues to rise...
Anyone use this fan before & any different results? Or could it be something else? The radiator, water pump, hoses & thermostate (160) are all new.
Thanks!!!!
Anyone use this fan before & any different results? Or could it be something else? The radiator, water pump, hoses & thermostate (160) are all new.
Thanks!!!!
Racer
Joined: Apr 2005
Posts: 494
Likes: 2
From: rockwall tx
i would put the small spoiler under the front to divert air up into the radiator and make sure the foam between the hood and the top of the radiator is still there, that keeps air from flowing over the top of the radiator.
Safety Car
Joined: Nov 2004
Posts: 4,359
Likes: 57
From: Mundelein Illinois
Are you sure you don't have air in the cooling system. Once the car cools down remove the radiator cap and check fluid.
Did you replace the temp sending unit. Is it matched to the guage?
Did you replace the temp sending unit. Is it matched to the guage?
Racer
Joined: Jan 2007
Posts: 385
Likes: 3
From: RTP NC
I am having issues with my 78.(with 350) .. I just recently fired her up after a complete rebuild... I am running Flex-a-Lite 210 twin electric fans which seem to pull alot of air but the car still heats up to around the 250 mark when sitting still & does not go down when I start moving. It continues to rise...
Anyone use this fan before & any different results? Or could it be something else? The radiator, water pump, hoses & thermostate (160) are all new.
Thanks!!!!
Anyone use this fan before & any different results? Or could it be something else? The radiator, water pump, hoses & thermostate (160) are all new.
Thanks!!!!
I just bought some pipe insulation from Home Depot (3/4 Foam) and used it to seal around my Radiator, top, left and right side. There was a 2 inch gap at the top of the Radiator where the stock air intake was and probably an 1 inch gap on each side of the Radiator. That has lowered my operating temp about 15-20 degrees.
Good Luck,
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
PUll the thermostat out completely, and try it....
after that we get technical....I assume your radiator has been at least flow checked, and is clean of trash that may block airflow....if you have a/c make sure there is not some damn bag or something in there between the a/c coils and rad.....
after that we get technical....I assume your radiator has been at least flow checked, and is clean of trash that may block airflow....if you have a/c make sure there is not some damn bag or something in there between the a/c coils and rad.....
Le Mans Master
Joined: Apr 2004
Posts: 7,106
Likes: 38
From: Newark DE
first of all, that 160ş t-stat doesn't do anything about how high your operating temp will be, only the minimum operating temp. If you still have cats and other emission control equipment on your car put a 195ş back in, if the emission equip has been removed put in a 180ş t-stat.
are you sure that the t-stat you have in there now is even working correctly? Most of the t-stats fail in the closed position blocking coolant from flowing. better units like the Robert Shaw brand (also sold under the Mr. Gasket brand name) are better and if they fail still allow coolant to flow.
is the radiator still the factory rad? if so have you had it flow checked? If it's aftermarket replacement is it an aluminum radiator?
does your lower radiator hose have the internal spring?
do you have all the radiator and shroud seals in place?
do you have the correct airdam under the nose of the car?
is your waterpump still the original unit? if not, was it a rebuilt unit or a new replacement and if so what kind? the factory waterpumps worked fine. Rebuilt units use a different impeller and they are not as efficient in moving the coolant thru the unit.
are you sure that the t-stat you have in there now is even working correctly? Most of the t-stats fail in the closed position blocking coolant from flowing. better units like the Robert Shaw brand (also sold under the Mr. Gasket brand name) are better and if they fail still allow coolant to flow.
is the radiator still the factory rad? if so have you had it flow checked? If it's aftermarket replacement is it an aluminum radiator?
does your lower radiator hose have the internal spring?
do you have all the radiator and shroud seals in place?
do you have the correct airdam under the nose of the car?
is your waterpump still the original unit? if not, was it a rebuilt unit or a new replacement and if so what kind? the factory waterpumps worked fine. Rebuilt units use a different impeller and they are not as efficient in moving the coolant thru the unit.
Last edited by BarryK; Aug 15, 2007 at 07:40 PM.
Burning Brakes
Joined: Sep 2004
Posts: 1,117
Likes: 0
From: San Jose CA
Wondering if the gauge is right. If it reached 250 and kept climbing, I believe coolant should be boiling and you might see steam comming out of around radiator cap area.
Mine does like crazy when it overheats.
Mine does like crazy when it overheats.
Burning Brakes
Joined: Aug 2006
Posts: 1,155
Likes: 0
From: San Diego California
All good advice above. The shrouding is very important to direct all the air thru the radiator. Also, whats the CFM rating on that electric fan? I understand that we need a minimum of about 2200-2500. A recent article in Car Craft indicated that most manufacturers specs are a litte misleading and too generous, because they were calculated with no obstruction in front of the fan- unlike your engine bay and radiator.
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Team Owner
Joined: Nov 2004
Posts: 20,705
Likes: 25
From: Sorrento Italy
...i have your very same fans, the best you could have, so you need to look elsewhere. also, a front spoiler won't do much difference, if your overheating is that bad, it can only slightly improve a fresh cruising at a certain speed.
maybe you have a rad blocked? air in the coolant stream? or simply your guage reads a false temp? at 250f you should get in a dante's inferno of steam...
maybe you have a rad blocked? air in the coolant stream? or simply your guage reads a false temp? at 250f you should get in a dante's inferno of steam...
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
I am with Gene, Barry, Panic and Rij. Its got nothing to do with the chin spoiler. If your getting that hot for real, there is air in the system or the thermostat is stuck, Its a waterflow issue, not air flow.
As suggested, remove the themostat and insure you have waterflow and make sure the hoses are not collapsing. Get a new 180* thermostat, drill a 1/8" hole in it and put it back in. The hole will make sure the trapped air can get out so you have a big hot bubble in there
As suggested, remove the themostat and insure you have waterflow and make sure the hoses are not collapsing. Get a new 180* thermostat, drill a 1/8" hole in it and put it back in. The hole will make sure the trapped air can get out so you have a big hot bubble in there
Burning Brakes
Joined: Nov 2006
Posts: 893
Likes: 7
From: Orange Park Florida
Silly question, but, are your fans pulling air, or pushing air, through the radiator? Check to make sure both are pulling air through the rad towards the engine. I've seen an instance where one fan was pushng while the other was pulling - not much good at cooling.
Pro
Joined: Oct 2006
Posts: 564
Likes: 0
From: London
Exactly what i was thinking.
Burning Brakes
Joined: Jul 2001
Posts: 853
Likes: 0
From: Foxfield, Co
He said he overheats idleing, that should have nothing to do with chin spoilers or radiator seals ( if while moving then yes) so his problems are more in the bad thermostat, fans not working correctly, water pump not flowing good enough or too retarted timing catagory. My first guess would be to be sure timing is set correctly and that vacuum advance is working and running off of manifold vacuum.
Greg
Greg
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
Hes got an air pocket in the system.....or his temp gauge is off....250* would be blowing coolant everywhere..
I would also double/triple check the timing...too much advance or retard will make em get hot mysteriously for no reason.
BTW running a 160* stat will give you a lower operating temp IF your cooling system has the capacity to keep it there. On all the LS1/6 cars, we run 160* stats and operating temps are at 160-175*.(assuming you have the fans tuned to come on at 170*)
I would also double/triple check the timing...too much advance or retard will make em get hot mysteriously for no reason.
BTW running a 160* stat will give you a lower operating temp IF your cooling system has the capacity to keep it there. On all the LS1/6 cars, we run 160* stats and operating temps are at 160-175*.(assuming you have the fans tuned to come on at 170*)
Race Director
Joined: Nov 1999
Posts: 10,643
Likes: 8
From: Foxfield CO 1970 Convertible
They come out of the box ready to be wired for either direction. Make sure they are spinning the right way.
Melting Slicks
Joined: May 2007
Posts: 3,246
Likes: 4
From: Bay Area CA
I once had an air pocket in a '78 trans am. Happened after I took out the block coolant plugs, and drained the block, just like a rebuild would be,, dry block. Gauge was tacking. What I did was, Got a gal of 50/50 mix, with the engine COLD, take off the rad cap and just let it sit on the filler neck. start the car and let it run. Peak under the cap, cooland will sit untill the thermostat opens up, the coolant level will drop out of sight and you'll see the coolant shooting through the Rad vanes. At this point use the Gal of 50/50 to fill 'er up, and put the cap back on. Other possibilities, as have been stated,, thermostat stuck closed or water pump not working.
Pro
Joined: Sep 2004
Posts: 595
Likes: 0
From: Boston MA
I once had an air pocket in a '78 trans am. Happened after I took out the block coolant plugs, and drained the block, just like a rebuild would be,, dry block. Gauge was tacking. What I did was, Got a gal of 50/50 mix, with the engine COLD, take off the rad cap and just let it sit on the filler neck. start the car and let it run. Peak under the cap, cooland will sit untill the thermostat opens up, the coolant level will drop out of sight and you'll see the coolant shooting through the Rad vanes. At this point use the Gal of 50/50 to fill 'er up, and put the cap back on. Other possibilities, as have been stated,, thermostat stuck closed or water pump not working.
I had the same problem and this fixed it.
Run it with no cap on, as soon as you see it move start adding fluid.
Also, make sure there are no radiator hoses that are higher than the cap. The cap has to be the highest point in the system. if not air will be trapped at the highest point.
Thanks,
Joe
Thread Starter
Instructor
Joined: Sep 2006
Posts: 211
Likes: 0
From: Searcy Arkansas
first of all, that 160ş t-stat doesn't do anything about how high your operating temp will be, only the minimum operating temp. If you still have cats and other emission control equipment on your car put a 195ş back in, if the emission equip has been removed put in a 180ş t-stat.
are you sure that the t-stat you have in there now is even working correctly? Most of the t-stats fail in the closed position blocking coolant from flowing. better units like the Robert Shaw brand (also sold under the Mr. Gasket brand name) are better and if they fail still allow coolant to flow.
is the radiator still the factory rad? if so have you had it flow checked? If it's aftermarket replacement is it an aluminum radiator? It is an aftermarket copper... Bought new....
does your lower radiator hose have the internal spring? No Spring in the hose...
do you have all the radiator and shroud seals in place? The twin electric fans have a seal around them that fits up against the red... I do not think the stock fan will fit?????
do you have the correct airdam under the nose of the car? No Air-Dam
is your waterpump still the original unit? if not, was it a rebuilt unit or a new replacement and if so what kind? the factory waterpumps worked fine. Rebuilt units use a different impeller and they are not as efficient in moving the coolant thru the unit.
are you sure that the t-stat you have in there now is even working correctly? Most of the t-stats fail in the closed position blocking coolant from flowing. better units like the Robert Shaw brand (also sold under the Mr. Gasket brand name) are better and if they fail still allow coolant to flow.
is the radiator still the factory rad? if so have you had it flow checked? If it's aftermarket replacement is it an aluminum radiator? It is an aftermarket copper... Bought new....
does your lower radiator hose have the internal spring? No Spring in the hose...
do you have all the radiator and shroud seals in place? The twin electric fans have a seal around them that fits up against the red... I do not think the stock fan will fit?????
do you have the correct airdam under the nose of the car? No Air-Dam
is your waterpump still the original unit? if not, was it a rebuilt unit or a new replacement and if so what kind? the factory waterpumps worked fine. Rebuilt units use a different impeller and they are not as efficient in moving the coolant thru the unit.
Sorry for the delay... Sick kid... had to set this aside for a few days....
Thanks!
John
Thread Starter
Instructor
Joined: Sep 2006
Posts: 211
Likes: 0
From: Searcy Arkansas
Found part of the problem (the big part)
I did some looking at the fans and one of the blades on the passenger side of the fan had broke at the base and jammed into my radiator which overloaded the fuse so at that point there was no fans at all.... Darn thing was whistling like a train when I shut it off from the steam coming out the overflow tube....
Anyway... I got the fan replaced and there does not seem to be any damage (water/oil leaks ect...) and is running fine...
I do have another question about exactly how hot these things are suppposed to run? I am still get around the 210 degree mark while driving down the street.... Is this normal????
Thanks again to everyone for their input... This forum is the BEST!!
Anyway... I got the fan replaced and there does not seem to be any damage (water/oil leaks ect...) and is running fine...
I do have another question about exactly how hot these things are suppposed to run? I am still get around the 210 degree mark while driving down the street.... Is this normal????
Thanks again to everyone for their input... This forum is the BEST!!
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
I did some looking at the fans and one of the blades on the passenger side of the fan had broke at the base and jammed into my radiator which overloaded the fuse so at that point there was no fans at all.... Darn thing was whistling like a train when I shut it off from the steam coming out the overflow tube....
Anyway... I got the fan replaced and there does not seem to be any damage (water/oil leaks ect...) and is running fine...
I do have another question about exactly how hot these things are suppposed to run? I am still get around the 210 degree mark while driving down the street.... Is this normal????
Thanks again to everyone for their input... This forum is the BEST!!
Anyway... I got the fan replaced and there does not seem to be any damage (water/oil leaks ect...) and is running fine...
I do have another question about exactly how hot these things are suppposed to run? I am still get around the 210 degree mark while driving down the street.... Is this normal????
Thanks again to everyone for their input... This forum is the BEST!!
77 350/th350 using built inradiator cooler
3 row oem c/b rad
no spring in new hose
180° RS tstat
stock fan and clutch
long headers
dual exhaust w/dual cats
other emission stuff gone
edelbrock intake
qjet rejetted
hei recurved
NO FOAM under hood anywhere
stock chin spoiler
front wheel splash guards removed
Stays at 180° all the time, 3800rpm on the highway or stop and go traffic in 90°+ temps.
Thinking of going to 195 tstat.
Gauge is accurate and stock GM isn't too bad after all.
Last edited by noonie; Sep 4, 2007 at 10:15 AM.