My '55 tbird with a 351 Cleveland runs about 200* on a 90* day just driving " normal" around town. Out on the road it is 180*. Engine has Edelbrock 180* intake, 750 Holley, mild cam , headers, so nothing to wild. I installed a 2 row aluminum radiator, 16" electric puller fan on shroud that came with the radiator. No engine driven fan, stock water pump. If I let the engine sit and idle on a 90* day, it will get up to 230* . Never throws out any water.do I need to worry,??
Just don’t let it idle! If it never blows it stack, you are ok! Cooler temps are really just for peace of mind. But you are running close to the limit and no cushion. Bones
230 is safe, 240 is on the edge of trouble.... I have a car that behaves pretty much like that, and I don't worry about it too much. I do try to not get stuck in traffic much when it's hot out.
I also see 230 and climbing sometimes, and will stop for a break if possible. My cooling system is about maxed out every which way. Been thinking about adding an air to oil cooler. Not sure it will help much but A) already have one and B) already have a remote filter plumbed. Anyone have experience?
"Too Hot" = coolant changes from liquid to gas; or the pressure exceeds the rating of the cap and blows out the expansion tank. Or when the engine blows a cylinder head gasket; or the pistons start to make contact with the cylinders. That's too hot. The exact point of 1 or more of those things happening is not the same for every engine. I'm uncomfortable with the gauge showing 230, nervous as a ***** in church. But some modern cars tend to run that temp regularly, still I don't like it.
It's a possibility your water pump is turning too slow at idle and the byp*** is byp***ing too much. If it has a byp*** hose add a plug to it with a 1/8" hole because the engine is circulating too much water not going thru the rad. To test your water pump speed at idle. Start cold, take off rad cap drain off 1" of coolant, start engine and watch inside the rad, when you know the thermostat is open, do you see water movement? If not raise idle slightly like to the first level of when choke is on. If you now see water movement get a smaller pulley.
It’s not over heating but it’s not great either. how big is the rad? Length width? What brand fan? Most of the cheap ones don’t do **** except restrict airflow. can you put a mechanical fan and shroud? what pulley is on the water pump? Oem or underdrive? what temp t/stat? ive used “water wetter” product in a few of my cars that ran warmer then I liked and with glycol 50/50 water mix and a bottle of water wetter dropped temps by 10* it’s basically soap without the bubbles and breaks the surface tension of the water , so it “hugs” the block better to help dissipate heat. It’s cheap so try it.
No thermostat. The br*** thermostat byp*** is plugged so all the coolant is going through the radiator.
Well. Ya kinda need one. Or at least a restrictive of some kind. The water is not staying in the block or rad long enough to either pull the heat out of the engine Or dissipate out into the atmosphere. Gosh!
Either an engine drive fan / shroud (stock?) or an electric fan with thermostatic switch will finish your system off. Otherwise, you are doing well IMHO.
First thing I would try is putting a thermostat in it. They're only a couple of dollars so a very cheap experiment. I'd start with something in the higher temp range, 185 or 195, then get it up to operating temps and let it idle for a while, see if that helps. As Vandenplas said, the coolant might not be in the radiator long enough to release it's heat, it is possible to cycle coolant too fast and lose some cooling efficiency. A thermostat is not just for faster warmups, it's also to regulate the amount of time coolant is in the radiator before it cycles back through the engine.
I refuse to be ****ed in on this "old wives tale". Why do some people not understand why High Performance/High Flow water pumps were invented and manufactured? Duh? To move water too rapidly? To cause engines to overheat?
For years I toyed with air cooled motorcycles running cylinder head temp gauges. 300-350 degrees was pretty normal, some ran near 400. Makes 230 seem mild. What about about air cooled VWs etc?
vws are 300-400 I could see temps of 500 on them on really hot days or guys who put all the “ cool chrome” heat shields on em ! make a liquid cooled system look down right cold !!!
I'd say the "upgrade" to the 2 row aluminum radiator with the attached electric fan was a move in the wrong direction. It may be time to re-evaluate that change. 230 is hot enough to put me on edge and make me watch the temp gauge, but its probably not hot enough to hurt the motor. An oil temp gauge will give you a better picture of what the motor is dealing with. Gene
Why the hell do guys always pee their pants when they stick a later engine in their car and it wants to run at it's normal ******** temperature for the vehicle it left the factory in? Doesn't make a damned bit of sense but the minute guys put a later engine designed to run at 200 in an old car they **** because the engine still wants to run 200. That engine probably left the factory with a 195 thermostat in it. Looking up a 71 Mustang on Rock auto the standard thermostat for a 351 Cleveland was 195. 200 going down the road is just operating temp.
if it's 180 degrees going down the road and warms up at slow speed / idle you are not getting enough air flow. i personally would not be comfortable with 230 degrees...and there is no reason for it. i can't see what you have so i can not make a recommendation what i can say is i have 4 hot rods with SBCs and all will idle all day at 180 degrees on hot days
Place a paper towel above the fan when the car is running. If it gets ****ed into the fan, placement is good. If it gets ****ed into the radiator, you shroud is all wrong. Thus, heating problems.
Remember the Cooling rule of thumb. Runs hot at low speed and idle - not enough fan. Runs hot at highway speed - not enough radiator.
A thermostat is a must IMO, but I would also look at the fan/shroud. If the shroud doesn't cover the entire radiator, then the fan will not cool the entire radiator. In other words, the fan will not pull air across the entire radiator surface.
If you don’t have a thermostat I would definitely install a restrictor in it. When I was going through my heating problems I bought a water pump from mondello (the Olds gurus) they recommend a restrictor so I used the one that they recommended. I used their pump because it has a redesigned impeller to stop cavitation.
The Jalopy Journal
