Hello All,

I have about 180ish miles on my car since the rebuild and, for the most part, all is well. However, the car runs hotter than I would like it to. From what I have learned from talking to people locally, the car should run about 190-195. On here people seem to think that it can run hotter than that. Where should it be? Its a 355 with mostly stock heads, and a mild cam. It is topping out around 210 or so with the new setup. I drove it earlier today while it was 92 degrees or so and sunny. My new setup is two 14 inch electric fans mounted opposite of one another blowing in the same direction. (One is on the front side of the radiator, all the way to the left pushing towards the motor, and the other is on the rear side of the radiator all the way to the right, pulling towards the motor) The fans are controlled by a coolant temperature sensor that kicks both fans on at 160 degrees. The motor seems to climb to temperature more slowly once the fans kick on but it is still getting to the 210 mark. Before going to the electric, I also tried a shroud for the OEM fan, and both 195 and 165 degree thermostats. Now I have a hollowed out thermostat in there, just to restrict the flow. The radiator is almost completely covered by the fans, I don't know what else I can do to get more cooling in this thing. Any ideas would be great! Thanks in advance, and sorry that this is a book!
Doug

i run my motor at 200-210 all day and that doesnt hurt it one bit,but from what u described it seems as though yours should run allitle cooler but not much,there is a couple things i would suggest,first of all what style radiator are u running?how many core? obveously an aluminum unit well help a ton because alluminum will disipate heat faster,also u can check and make sure that the radiator cap or the filler tank wich ever u have, is the highest point in the cooling system,where ever u add the coolant too should be,if its not your never going to get all the air out of the cooling system causing a hot condition.allso make sure your fans are pulling not pushing,if u want too u can buy the restrictor plate kit moroso makes and play with the diatmeter of the hole in the t-stat housing this will affect heat as well.i run a 205 degree stat in my 11:1 383 stroker,ive ran into hot conditions on the race car and found the 5/8 restrictor plate cooled best so u have to play with that in my experiance every motor likes a little differant ristrictor or t-stat. also check to see if your loosing coolant wich will cause a hot condition,this can be caused by a radiator cap that has the pressure spring wore out,or it isn't a high enuff pressure rated cap, these are just a few things ive ran into in my hot rodding endevers so just look everthing over good and i hope it works out!!-
Dan:thumbsup:

Two initial comments. Electric fans and an overbored engine.

Electric fans suck; or blow, depending upon there orientation. But no matter how you install them, that 1/6th horse electric motor (if you buy the biggest and baddest) will never move as much air as a fan powered by a small block Chevy. There isn't enough power to turn the stock metal bladed fan if you put ten or twenty of those electric fan motors together. Because of this electric fans are doomed to cause any motor that has them to run firecracker hot, just like all of the cars the majors make do.

Second: Every time you bore into the cylinder walls you make them thinner, which allows the heat to pass through the cylinder walls faster than the non-overbored cylinder walls of a stock engine. So an engine that has been bored is normally going to be hotter running, than it was before you bored it. An example comes to mind. You are in steel plant protected from the heat of a blast furnace by a steel wall. Now which do you think is going to be cooler, the wall ten feet thick or the wall an eighth of an inch thick. Steel doesn’t conduct heat as well as copper or aluminum but it does conduct it.

Big Dave

As for the specs of the radiator, I do not know how many core the radiator is. If I remember correctly, it was about twice the thickness of the original unit that was being replaced a while back. It is not an aluminum unit, however I would think that it is plenty enough to cool the motor. The two fans are plenty big enough to cover nearly the entire radiator surface and are the specs recommended by the manufacturer to cool this type of motor. That is why I would assumed that they would cool the motor just fine. As for the fan being run by the motor, I tried that route before I took the electric fans and it was getting me absolutely no where. The electric setup that I have on there now is already doing much better than the OEM fan and shroud setup. With the shroud and fan, it got much hotter. It was steadily climbing to about 220 when I shut it off. I had considered an aluminum setup but wanted to continue playing around with this radiator to see if I could get it to work. The radiator and the overflow tank are the highest point of the cooling system. They sit at about the same height and are definitely at the highest point. I think that my radiator and fan setup is very sufficient. My next move was to go back to one of the complete thermostats and just run water and see where that gets me. Also maybe add some water wetter to it and see how that goes. If I was to do this which thermostat should I put in? The 165 kept it cooler longer, but I think the 195 would be closer to the temp it should be running. Thanks for the replies!
Doug

If your car cools down at sustained speeds above thirty five miles per hour, then you have an issue with the fans.

If the car doesn't cool at high speed you do not have enough radiator to shed the heat, or you have a water circulation problem (thermostat, pump under driven by wrong size pulley). A BBC radiator will cool any engine you can put between the fender wells. It will be 23" wide (inside the tanks) by 19" tall and have four 1/2" wide copper tubes. Not big enough? An Impala radiator can go in there if you do not mind cutting out part of the radiator core support to increase the area (27" inches wide inside the tanks), but it shouldn't be needed.

Aluminum radiators use two tubes 1" to 1-1/4" wide to increase surface area without disrupting the air flow. Because aluminum is stronger than copper it allows you to run higher radiator cap pressures that allow a higher boiling point (the engine doesn’t worry about how hot it gets until it gets around 420° F were the motor oil breaks down) so modern cars all run at 230° F and will give you a computer error if it falls below 210° F to burn off pollution gasses. Modern cars all use aluminum radiators and electric fans, not because electric fans are better than mechanical fans but because the motor is sitting in the car sideways and to clear the hood lines.

A properly set up mechanical fan and shroud with the correct size radiator will keep any car cool. My 582 uses such a system and in 95°F external air temps with 75% plus humidity it never gets above 190° F in traffic. I have a Griffin aluminum radiator, a stock seven blade fan with a Flex-a-lite thermally activated fan clutch, a 160° F Mr. Gasket thermostat (Stant) and run Prestone anti-freeze at 60%. My pulleys are by March but they are all of the stock diameter and they turn an Edelbrock high volume aluminum water pump.


Big Dave

My 355 was running hot too. I use a single 16" electric fan and my motor is fairly built. With the 3 core brass radiator it was running 200-220 or so. I tried using a high flow thermostat of various temps from 160-195 all with zero change. It would run fine in coolers temps like after sunset or before it got too hot. Changing to a water restrictor helped alot, it now stays below 210 which is just fine.

Having said all that, I just installed a Summit aluminum radiator today. It was a perfect fit and took about 30 minutes to install. I didn't get a chance to run it with the new radiator but I'll check it tomorrow...Although it's only supposed to get to 82 degrees tomorrow. I'm hoping to have to put a thermostat in mine after changing to the aluminum radiator. I'll let you know.

Brandon

The aluminum radiator made a huge difference!!! 20-30degrees cooler.

I'm glad that fiasco is over. You might give that a try.

Brandon

I have been thinking about going to an aluminum unit. The car stays under 210 even when the temp is 90ish outside. I just really don't like it running that hot though. It does take it some time to get to that temp too. Depending on if I am in traffic or not, the car will stay cooler longer if I get right on the highway, but will heat up faster if I am sitting in traffic. When sitting in traffic, it takes about 10 to 15 minutes for the engine to reach the 210 mark. Once it gets to 210 it stops. It hasn't run hotter than 210 since I installed the electric setup. I also moved my sensor for my gauge because it seemed to be really close to the header in the previous spot. That however, did nothing. The aluminum radiator and maybe a high flow water pump will be the next things to go in Im sure. Till then I guess I will just cruise her at night:thumbsup:

This might be stupid, but maybe the heat outside could affect it to??

I have my engine bored & it runs (at night) 180-190, and during the day on the highway goin' 80 about 200. He hates sitting though, and can get up to 215 if I sit too long.

I don't think you really have that much to worry about temp. wise.

I just have the standard fan, though, no electric ones- thinking about possibly doing the upgrade at some point, though. :)