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91CamaroDude 10-25-2011 06:58 PM

Cooling Issues. Even With No Thermostat
 
3 Attachment(s)
I have swapped out a sbc 350 into a 91 camaro, and for whatever reason I cannot keep it cool. If im zipping around town only going about 5 miles it will stay at 180 with no thermostat the entire way. If I go any further it will climb and climb until an uneasy 230. Needless to say I check it with a heat gun and pull over when necessary. I bought a radiator for a camaro z28 with a 5.7 assuming that was where my issue lied (because originally it had a 3.1 radiator)

Im actually baffled because they are identical to the T in size. Same dimentions all the way around with a 1 row. I am using an electric fan wired to a switch so I keep it running as soon as I turn a corner. It has the original shroud, which as I read more and more does wonders to keeping it cool.

Heres another one, being it a new radiator I popped the cap one day and realized this flaky brown crap floating around ( see the pictures ) so I had assumed the coolant jackets inside the block probably had some built up deposits since it is from the late 70's. I put in some Coolant Cleaner and have yet to flush it out only because I have ran it probably a total of 30 minutes run time with the cleaner in.

My question is would I be correct on assuming those are deposits breaking down floating in there? And I have heard from everywhere 2 different sides to a thermostat. 1 that it is only used to get the motor up to running temp. 2 that it allows the coolant in the radiator to actually cool down before it enters the motor. < and if #2 is the case, why wouldnt a thermostat stay open all of the time if it reaches 190, essentially if it is open all of the time...thats just like running it without a thermostat..?

327NUT 10-25-2011 07:10 PM

#2 is correct....except the T-stat's small opening limits, restricts the flow or slows the coolant down so the air passing through the core can cool it down. Without the T-stat the coolant rushes through the core too fast and doesn't get the benefit of the finned area = HOT coolant all the time.

gmc1990rodder 10-25-2011 07:56 PM

surely need the t-stat try 195 degree second did u reverse flush the cooling system? its simple to do even if the engine isnt running...assuming u have a heater disconnect one hose,attach a water hose and a lil duck tape to hold in place lol turn on the water w/radiator cap off water should folw out off the top...if not try the water hose on the opposite heater hose... also did u dran the block by the to plugs on the bottom?? after u pull the plugs out and have no water flowing ouy of them..insert a small screwdriver thru the rust until it flows.... after u turn the water on allow to run thru system until it runs clear

killerformula 10-25-2011 08:36 PM

It sounds like you maybe had a thermostat in this car and then took it out to see if you could improve cooling? First thing's first, you do have to run a thermostat. Second, I would check the pressure in your system to be sure you've got proper pressure. Low pressure will cause you to overheat as well.

K

sbchevfreak 10-25-2011 08:44 PM

Make sure the chin spoiler and all air dams are in place. This era Camaro has a very small grille opening, and uses these pieces to direct airflow from under the bumper through the radiator core. If they are missing, it will overheat. You also need to have the t-stat in, for the reasons Cobalt mentioned.

91CamaroDude 10-25-2011 08:48 PM

O.o hmmm I really did not think about the decreased size in the thermostat would allow more water to cool vs leaving it open.

And no I do not have a heater hooked up just yet I'm still trying to figure out the main things first. Which I do understand if I had a heater hooked up that it would allow it to cool more even through the core. I have put my hose in, let it run a few minutes, pull a drain plug, fill her up, ect. I'm a little unsure where the rust would be at?

And never have I had a thermostat in here I just assumed that during august and September I would need as much waterflow as possible but it seems that it is wrong.

mike Crawford 10-26-2011 12:37 PM

I believe some cars also use the heater core as part of the cooling system .
If you get a hole in your heater core .. amd bypass the heater core,, The motor may overheat

malc 10-26-2011 03:34 PM

Quote:

Originally Posted by sbchevfreak
Make sure the chin spoiler and all air dams are in place. This era Camaro has a very small grille opening, and uses these pieces to direct airflow from under the bumper through the radiator core. If they are missing, it will overheat. You also need to have the t-stat in, for the reasons Cobalt mentioned.

IŽd go with this as well, that airdam is critical for highway cooling.

maddmechanic 10-26-2011 06:16 PM

air flow
 
the chin spoiler is a very important part of the cooling system om a modern auto it forces more air through the radiator. when the system is set up right the fan actually does nothing above 35mph or so. yes the t stat is also required to slow the water flow through the radiator so it cools. also make sure your heater hoses are at least hooked together most V engines need that flow to properly remove the air from the heads, if the heads have no water in them no cooling of the enging. i had a project once where i put a 455 olds in an 80s toronado and i actually had to add a larger chin spoiler to keep it from overheating at 25mph.

RPM 10-26-2011 06:46 PM

Check your timing very close, low timing will do exactly what you are describing. You need to run a thermostat in the motor.

John68040 10-26-2011 08:07 PM

Quote:

Originally Posted by gmc1990rodder
surely need the t-stat try 195 degree second did u reverse flush the cooling system? its simple to do even if the engine isnt running...assuming u have a heater disconnect one hose,attach a water hose and a lil duck tape to hold in place lol turn on the water w/radiator cap off water should folw out off the top...if not try the water hose on the opposite heater hose... also did u dran the block by the to plugs on the bottom?? after u pull the plugs out and have no water flowing ouy of them..insert a small screwdriver thru the rust until it flows.... after u turn the water on allow to run thru system until it runs clear

They make plastic t-valves for this, I've got one in my car. You cut a section in the line where it goes to the heater core and clamp it in. It's got a threaded cap, and with an adapter you can screw on a garden hose. It makes flushing the coolant nice and easy.

RippinRon 10-27-2011 05:32 AM

Quote:

Originally Posted by sbchevfreak
Make sure the chin spoiler and all air dams are in place. This era Camaro has a very small grille opening, and uses these pieces to direct airflow from under the bumper through the radiator core. If they are missing, it will overheat. You also need to have the t-stat in, for the reasons Cobalt mentioned.

I third this, been there done that! The chin spoiler is the most important part in keeping these cars cool while moving.

91CamaroDude 10-27-2011 07:53 AM

Well I think the thermostat did me wonders. Would have posted earlier but my battery decided to drain out on me and wouldnt let me start. I just never would have thought that a t-stat would be the solution I was looking for. Again thanks for all your guy's help and ideas here.

Cody

ap72 10-27-2011 08:53 AM

The thermostat does NOT let the coolant cool down easier, whomever thinks that needs to pull their head out of their ***. On a street car a thermostat is necessary though to maintain enough heat in the engine, running too cool is just as bad as running too hot. As mentioned, system pressure reduces localized boiling, which is important, and airflow across the radiator is needed to remove the heat from the cooling system.

MARTINSR 10-27-2011 09:02 AM

I don't believe anyone mentioned the fan shroud. If you are "driving around town" you are likely not moving fast enough for air to cool the coolant in the radiator and you MUST have a fan shroud so the fan pulls the air THROUGH the radiator not from around it.

Brian


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