sbc overheating. 650hp rated aluminum radiator

having overheat problems...i think.

when drivng the truck runs a nice 150-175degress.

but if i get stuck at a light it has reached as high as 220degrees!

radiator is all aluminum bolt in style for the 1951 chevy truck. its rrated for 650hp engine even though my 350 sbc is stock.

im not running a tstat. radiator is water only. hoses are all new. non collasped.

running an electric fan covering the entire radiator span as a pusher. i have no room to mount as puller.

what can i do guys?

could it be my timing? the truck starts right up with slight touch of the key iginition.

could it be the liquids? should i go with a 50/50 mixture? or is there anther liquid out there i could use to help cool it?

my spark plugs are the original ones when i first bought the engine....should i replace now?

could it be the place i mounted the temp sending unit? the unit that came with my new guages was huge and would only fit onto my water pump.

 

I've run plenty of cars with straight water and no t-stat, never any problems,

Could be the timming, could be running lean, could be a small head gasket leak, could be bored over a little to far.

I have plenty of room in my 48 chevy truck with a 350 for a fan.

What radiator do you have?

 

Put a 185 T stat. At idle the water is moving to fast to transfer the BTU's (heat ) to the Alum Rad. At speed the supply flow of cool ambient air is plentiful.
Needs restriction to slow down the water, in order to transfer the heat out of the water.
And course a well made shroud is the ticket.
My 502 run's a 185 stat, only very hot day's it get's to 200 degree's

 

I'm thinking it is an airflow issue at low speeds. If the temp drops as soon as the truck is moving at any speed at all and then goes up when you slow down to a crawl or stop at an idle the pusher fan just flat isn't pushing enough air.

If you have the sending unit in the water pump rather than the block, head or manifold you are measuring the temp of the coolant returning from the radiator and not what it is in the block or leaving the block.

And yes I would run a 50./50 mix of quality antifreeze. It may not get the temp down any but it helps prevent crud buildup in the cooling system. This day in age it is more than counterproductive to run straight water. It is easier to clean up if the radiator cap pukes it out though.

If you don't put a thermostat in it try putting the hulled out washer part of a thermostat in it. I've done that on my own rigs a number of times and it gives just enough restriction to slow the flow down so it can transfer the heat both ways. You not only have to transfer the heat from the block and heads to the engine but from the radiator to the atmosphere.

 

its a no name radiator off ebay....here are the specs

<TABLE border=0 cellSpacing=1 cellPadding=1 width="100%" bgColor=#3789ae><TBODY><TR><TD style="FONT-WEIGHT: bold" bgColor=#ffffff height=23>Year: 1951-1954
</TD><TD bgColor=#ffffff rowSpan=4>
</TD></TR><TR style="FONT-WEIGHT: bold"><TD bgColor=#ffffff height=23>Core Size: 21-1/2"×17-1/8"×2-1/2" 3 row</TD></TR><TR style="FONT-WEIGHT: bold"><TD bgColor=#ffffff height=23>Inlet/outlet: 38/45mm</TD></TR><TR style="FONT-WEIGHT: bold"><TD bgColor=#ffffff height=23>overall size: 22-3/8"×21-7/8"×3"</TD></TR></TBODY></TABLE>
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Yes,airflow...heating up in traffic means more fan needed..or better fan..or shroud .
Think about the 650 HP rating on the radiator..How much power is your engine developing when stopped in traffic?

 

How many amps is that electric fan?
Most off brand fans are liars when quoting CFM.
Electric fans work better as a puller- on engine side of radiator.
Make sure fan is spinning in correct direction- you can verify w/ a piece of paper. Put a thermostat in it.

 

its a curved blade fan. i believe its rated for 2200 cfm. im not sure on the amps. i might have to bust out the meter.185 stat then? or less?

yes its spinning the right direction.

 

i looked up online parts place. they have 160 degree stat. im not sure what i should get. what yall think? im not running a heater. summer only truck.

 

Is the problem new (mechanical failure)? I used to have this issue with my pickup, 160 degree t-stat install, puller fan, and new water pump fixed it.

 

Core Size: 21-1/2"×17-1/8"

I have a 650 hp engine, and my radiator core is a lot bigger than that....and it gets up to 220 or so in traffic, with a big well shrouded clutch fan. The important thing is that it never boils over.

btw 220 isn't anything to worry about, but running at 150 is kind of cold. I'd put a 180 thermostat in it, along with some antifreeze, and a pressure cap that is recommended for the radiator (probably 13-16 psi), and see how it does.

Seems that the last thing some folks think about when doing an engine swap, is leaving room for a fan. It's one of the first things I think of.

 

A thermostat would be the very first place I would start. I can't imagine why you would run without one. The fan mounted in a pusher capacity would go away as quickly as possible as well in favor of a mechanical with a shroud. A thermostaic clutch fan is the only way to fly. Two problems with the electric as you have it now are that a fan is only partially as efficient mounted in a pusher manner, and it also partially blocks incoming airflow. Bad deal both ways around it. Down here in the heat, you won't find an electric fan other than OEM stuff that will last more than a summer or so, period, so most of us here in the desert just say no...
My car out fitted the way I suggest above with a 430 horse aluminum headed 360 will sit in traffic on a 118 degree day with the A/C on and never go above 195 or so.

 

the radiator cap that is on the radiator is the one that came with it. the radiator has not yet overflowed/boiled over. i think i heard it whistle though....not sure.

i guess you can say the problem is new. ive only put 140 miles on the truck so far....engine and frame is from a 92 silverado. body is 51 chevy. was a really good fit. just seeing that 220degrees kinda concerned me.

how hot is to hot for a sbc?

 

Newer models run pretty warm, 220 isnt dangerously high unless your motor is sensitive to detonation

 

Most of the time it's either water pump speed or ( water speed) through the radiator core. If the water flows to fast there isn't enough time to cool the water!..try a 5/8 restrictor in the thermostat housing or thermostat...any one! Try that first! 50/50 mix...or even Water Wetter. I've seen and built 800+ Hp dirt late model engines (4 blade GM Fan and no shroud) that run at 180 no problem. At best hp temps 210/230 WT and 240/260 Oil Temp. Look at your pulley ratios next....good luck!

 

Strap a Ford Taurus fan on that*****er.

 

If your runnin a 92 fuel injected engine, I cant believe you can get it to run at 150. 220 is pretty normal. If its an LT1 then I am even more shocked.

I dont think the injection ( if it is) comes out, and into a running loop until over 200. You are supposed to have a 195 thermostat in it.

A thermo/ antifreeze, and if you want water wetter should be good, if you have a good fan.

I do want to ask, who you bought the radiator off of?? I am lookin at one out of Michigan, 586 area code I think... Is that the same place?


TCI makes a chip, otherwise your fighting you computer, which will continue to try to heat the engine ... over 195

 

I had to previous cars that would run hot and this is how I cured the problem.
1. '51 Ford Gasser - 421 Pontiac, no thermostat and vacuum advance wasn't hooked up. The car would run 215. I added a 160 thermostat with bleed holes, hooked vacuum advance to manifold vacuum. Car ran at 180 after that.
2. '52 Chevy - stock 350, car ran at 180 but in traffic, would get to 210 and wouldn't come down, even if traffic moved. Mechanical fan pulled great. Radiator was flushed and a 160 thermostat was installed. Still ran warm until I got a new distributor. The mechanical advance was frozen and the car was always running retarded.

 

One word......

FAN!

Ditch that electric B.S. and install a good 17" or 18" Flex-a-lite mechanical flex fan.

 

Like mentioned use a shroud and a t-stat. 25/75 wont hurt. Helps keep ur water pump lubed properly.

 

Sounds like the water is flowing through too fast. Take a thermostat and gut it and then just put the part of the thermostat with nothing in the center and try that. It should slow the water down enough so that it stays cool.... Good luck

 

My 85 4x4 with a 350 runs 220 all the time, sometimes 230 and I have thrown everything but the kitchen sink at it and nothing has changed. I gave up and just drive it and it runs like a bat out of hell. love it..

 

you mite want to think about cooling components 2 5/8s thick electric puller fan, 2800 cfm at idle, works great put 3 in diff cars, no problems, 180 degree them, 13 lb cap. 40 ford coupe, small grille not alot of air flow, runs 190 195 with air on, 94 degree day at idle. fan sold by walker radiator. it works.

 

engine was switched over to a 2bbl gas. in the future it will be a 4bbl.

 

If car companies didn't need to install thermostats in there engines then why do they fit them? My 2c's worth is a 160 degree thermostat for a start then drive your ride and see what happens next! Beware of Chinese***** on e bay! Wayne

 

dont use water use coolant water boiles at 212 a 50 \50 blend should be good to 240 if the cooling system is good (ie hoses, radiator, and cap) try this before you spend a lot of money

 

new stat...160
anti freeze added....

now i can rule out something....

i watched the temp guage like a hawk. rose all the way to 225 then dropped to 160. then rose all the way up to 220 wth. is this right? or is my temp guage wronge?

while watching the temp g. i keep placing my hand on the radiator to see how hot it was getting. didnt get hot til the temp guage dropped the first time. so i guess the stat opened up.
i temp guage sending unit is located on the water pump itself. is this bad?

 

Are you running a hi-flow water pump? Have you used a infrared laser temp gun to see what the actual temp of your engine is? Are you satisfied that the gauge is reading properly?

You can buy a cheap mechanical temp gauge for $15.00. Boil it in some water with a candy thermometer to make sure it's accurate, and install it on your motor. Then you'll
know what's what.

 

is your guage at all accurate? Lots of recently made ones are not....
BTW 220 is actually OK in a Chevy engine newer than '90......
Take a cooking thermometer and stick it in the core of radiator and compare the readings of it and your guage-you may be suprised

 

Put the sending unit in the head.