383 running hot

[origcharger]

Forgot in my original post.. if you dont already have one... get an IR temp gun. HF has them pretty cheap. measure temp at thermostat housing, then measure temp at bottom hose see how much temp difference you have. IR temp guns are invaluable in diagnosing things.
Also as a kid I worked at a machine shop / parts store. I honestly can say I sold hundreds of lower rad hoses with springs inside. It did not matter if it was a Gates, or Goodyear hose, I vividly remember the hoses having springs when I restocked them.

Yeah they all used to come with the anti collapsing springs but you rarely seem them in the hoses sold today. Watching the lower hose while revving the engine should rule that possibility in or out.
I believe I would start by popping the water pump off and having a look to see what you have as it will never be easier than it is now before you start adding shrouds, fan....

 

[Ccas]

If you are getting up to 220 sitting or at slow speeds, then as mentioned, get an OEM style fan shroud and the largest mechanical fan you can fit and your temps should come down at least 10-15 degrees.

If your temps don't come back down at speeds of 30-40 mph, then you have a volume problem likely from that 3 row not operating at full capacity for any number of reasons or your motor is creating some additional heat also for any number of reasons.

If the latter is the case, then you just need to upgrade the radiator to a higher capacity unit or start chasing the gremlin(s) that are causing the extra heat. Since you aren't really officially overheating you don't have that far to go.

as said above, up to 210 is acceptable for the motor but I am never comfortable with the heat coming through the firewall at 210 nor how close I would be to the danger zone. That's a bit close for me. 190 is a perfect operating temperature and should be totally achievable.

 

[Nate S]

A clutch fan on the Engine Masters channel robbed 14 horse power from the engine - and the loses only went up from there to around 28 horse power.
Sorry Nate S your thinking has one big flaw - it is not about the power of the electric motor it is about the CFM of air the fan can move.
If your theory was even close to right every cooling system in every passenger car produced in the last 30 years would be in big trouble.

My theory is close to right, but not close enough. Pretty fair to call me out on it! There are other facets, fan speed at idle being a big one, coupling to radiator (shrouding) being another, fan diameter, blade design etc being a third. It's worthy to note though that the 5/14/28HP IS all from moving air, just how it's moved matters. Engine driven fans do move more air -at speed- . The newer cars that use the electric fans have much more efficient engines and pull through much more efficient radiators. Ever notice how long it takes for the heat to work in a new car vs old? An older design inefficient engine, using an original inefficient radiator, possibly with a bigger, less efficient cam is gonna be hard put to stay cool with an electric fan. Change the radiator and it can help but it looks like the OP has a stock radiator.

 

[Ranger16]

My Road Runner (383, 7 blade direct drive fan) is a survivor and still has the OEM radiator. It ran 200° and up to 210° on a hot day (even on the highway). In a long line waiting to get into the Hot Rod Power Tour it got up to 230°. That was it for me. When I got home I found a 190° thermostat in it (which is what the FSM called for). I replaced it with a 180° stat and ordered a shroud. Now it runs at 180° - 185° and rarely ever tops 190°.

 

[Moparhead61]

Nice wagon! If you didn't get it to run cooler after your next test drive, I would check the impeller on the water pump. I have seen them rust off . Which causes insufficient water flow.

 

[motorhead]

I have a friend with a 73 charger 400 motor. Fresh rebuild from previous owner. Ran hot, really hot, boiled the radiator over. Replaced the stat, still hot. Radiator flowed good. Tried electric fan, still hot. I put in a good brass stat and it never got over 190 on a hot day. Even took the electric fan back off and put it all stock.

 

[Moparhead61]

The lower hose spring is a very good thing to check. I've been there on 383 overheating. Mine was rusted to pieces. The hose WIll suck shut

 

[Don Frelier]

Ever notice how long it takes for the heat to work in a new car vs old?

I've found the newer cars heat up much more quickly. Smaller block and the thermostat is closed when it's cold so the radiator should have nothing to do with it. An electric fan it's off at that point unlike the old clutch or direct drive fan which is still working.
I had a Sebring with a 2.4l that would give heat in about 90 seconds even in very cold mornings. Simply amazing.

 

[Tim Ziegler]

Usually mother nature knew what she was doing. So often it goes back to work that was done. I like to run cool (180ish) in case I travel to AZ

 

[Tim Ziegler]

If I'm runnin to hot, 1st new therm then if that don't fix it the rad goes to a good shop that boils it out (re core?) and tells me the rad is good, shot, or on its last leg and might last a while

 

[ksurfer2]

My Road Runner (383, 7 blade direct drive fan) is a survivor and still has the OEM radiator. It ran 200° and up to 210° on a hot day (even on the highway). In a long line waiting to get into the Hot Rod Power Tour it got up to 230°. That was it for me. When I got home I found a 190° thermostat in it (which is what the FSM called for). I replaced it with a 180° stat and ordered a shroud. Now it runs at 180° - 185° and rarely ever tops 190°.

Maybe someone can help me understand this....I was/am under the impression that a thermostat will not have an effect on the temperature a engine runs at, just when the thermostat begins to allow coolant to flow through it.

If you have a 190 degree thermostat, when conditions cause your car to run at 200, it is wide open and flowing at its max. If those same conditions exist, a 180 degree thermostat won't change anything since the cooling capacity of the radiator/fans has not changed.

 

[Don Frelier]

Unless the thermostat itself is a flow restriction.

 

[RR1968]

I acquired my 66 Coronet station wagon last fall and am still getting a feel for it. It is running hot and my local radiator shop and I am working on troubleshooting it. The guy at the radiator shop says for an engine like this running at 220 is not a big deal but from everything I have read that seems pretty hot. Seems like closer to 190 is ideal. The car has an electric fan (installed by the previous owner) and we realized it wasn't working so we fixed that but that didn't seem to be help much. We have also changed the thermostat (the previous one was in upside down) and flushed the radiator. I have yet to take it on a long drive but in the short trips I have taken, even on the open road, it seems to be running way warmer than it should. Has headers now but I have exhaust manifolds that I am looking to put back on once I get the chance. Thanks in advance for your suggestions.View attachment 966190

I installed a Hi-Flow water pump on my car and it runs 180-190 in the heat of Florida summer. If sitting at a stop light it will creep up to 200.

 

[Mopar Bob RR]

I acquired my 66 Coronet station wagon last fall and am still getting a feel for it. It is running hot and my local radiator shop and I am working on troubleshooting it. The guy at the radiator shop says for an engine like this running at 220 is not a big deal but from everything I have read that seems pretty hot. Seems like closer to 190 is ideal. The car has an electric fan (installed by the previous owner) and we realized it wasn't working so we fixed that but that didn't seem to be help much. We have also changed the thermostat (the previous one was in upside down) and flushed the radiator. I have yet to take it on a long drive but in the short trips I have taken, even on the open road, it seems to be running way warmer than it should. Has headers now but I have exhaust manifolds that I am looking to put back on once I get the chance. Thanks in advance for your suggestions.View attachment 966190

I acquired my 66 Coronet station wagon last fall and am still getting a feel for it. It is running hot and my local radiator shop and I am working on troubleshooting it. The guy at the radiator shop says for an engine like this running at 220 is not a big deal but from everything I have read that seems pretty hot. Seems like closer to 190 is ideal. The car has an electric fan (installed by the previous owner) and we realized it wasn't working so we fixed that but that didn't seem to be help much. We have also changed the thermostat (the previous one was in upside down) and flushed the radiator. I have yet to take it on a long drive but in the short trips I have taken, even on the open road, it seems to be running way warmer than it should. Has headers now but I have exhaust manifolds that I am looking to put back on once I get the chance. Thanks in advance for your suggestions.View attachment 966190

I had a 69 Roadrunner for the past 12years. Fact. A/C car. Had the stock radiator and shroud. Ran a flex fan and a 195 t stat.
Been on the Hot Rod Power Tour twice in really hot weather. Never had an overheating problem. Even with the a/c on in 90 degree weather cruising around town. Shot it with a laser heat gun, hottest it ever got was around 205. The stock setup is the way to go in my opinion. Rebuilt the 383 a few years ago. 30 over , Lunati Voodoo cam a hair over stock specs. Took the headers off years ago and put on the stock hipo manifolds. The electric fan setup without proper shrouds plain sucks. Know a lot guys that removed there electric fans, went stock and ran the190/195 stats and shrouds. My timing is about 12 btc. One more thing, never put a 160 in it. I got schooled back in the early 70's when I was going out west in the summer. Car kept overheating and I stopped and Tucumcari New Mexico get a new stat. The old-timer said why you put in the 160 in the car and I said to keep it cool he said that's not the way it works. I put the stock 190 in that small block barracuda and had no problems after that. Good luck with your project

 

[diesel_lv]

Maybe someone can help me understand this....I was/am under the impression that a thermostat will not have an effect on the temperature a engine runs at, just when the thermostat begins to allow coolant to flow through it.

If you have a 190 degree thermostat, when conditions cause your car to run at 200, it is wide open and flowing at its max. If those same conditions exist, a 180 degree thermostat won't change anything since the cooling capacity of the radiator/fans has not changed.

Partially correct. A 190 thermostat isn't fully open at 190, closer to 200-205. If the engine is regulating at a steady 200, a 180 may allow the engine to regulate at 190-195. "May" The thermostat is what regulates the engines minimum operating temp. It allows the engine to get up to temp quickly, and allows for heater operation. People associate colder engine w more power because when they 1st start their engine or when it's particularly cold outside and eng temps show below normal, they think it's the cooler engine giving crisper throttle response. Its not, it's the cooler/denser air. Warm, 215 degree engine and cool dense air will always make more power.

 

[747mopar]

If it's running hot at cruising rpm's don't waste your time messing with the fan, your coolant system isn't up to the task. I'd start with confirming ign timing and carb tuning then move onto the radiator, thermostat, pump and hoses. As for everyone saying switch to a mechanical fan I say B.S. I see it all the time, people go out and buy an electric fan and never research the needed cfm but instead buy cheap. Damn near every modern car uses electric fans for a reason, they put out full cfm even at idle and don't rob economy by sucking hp.

I switched to electric a few years ago, I asked the knowledgeable guys here at FBBO how many CFM was needed and sized mine accordingly, no problems at all.

Having said that a properly operating cooling system should maintain close to the thermostat setting at cruising speeds with zero fan.

 

[toolmanmike]

I acquired my 66 Coronet station wagon last fall and am still getting a feel for it. It is running hot and my local radiator shop and I am working on troubleshooting it. The guy at the radiator shop says for an engine like this running at 220 is not a big deal but from everything I have read that seems pretty hot. Seems like closer to 190 is ideal. The car has an electric fan (installed by the previous owner) and we realized it wasn't working so we fixed that but that didn't seem to be help much. We have also changed the thermostat (the previous one was in upside down) and flushed the radiator. I have yet to take it on a long drive but in the short trips I have taken, even on the open road, it seems to be running way warmer than it should. Has headers now but I have exhaust manifolds that I am looking to put back on once I get the chance. Thanks in advance for your suggestions.View attachment 966190

All good suggestions - thanks...what would be a reasonable operating temp? And would you agree 220 is too hot?

220° is getting warm but not overheating. You didn't mention what degree t-stat you put in. Try a 180° and make sure your cap is good. I know fan blades are a power drain but they are quite efficient and with a shroud they can be even more so. A thermostatic clutch operating properly doesn't take much power until it locks up. Most drag racers don't use them. The electric fans are easier to control but you could use more fan. Your single fan, regardless of how much air it pulls, only covers 1/3 of the core. You need another one at least. Something like this would be good. Late model fans from the salvage yard may be good choices as well.

 

[Ranger16]

Maybe someone can help me understand this....I was/am under the impression that a thermostat will not have an effect on the temperature a engine runs at, just when the thermostat begins to allow coolant to flow through it.

This is from the Stant site. http://www.stant.com/index.php/english/products/consumer-products/thermostats/abcs-thermostats/

The thermostat has two important jobs:

• Accelerate engine warm-up: By blocking the circulation of coolant between the engine and radiator until the engine has reached its predetermined temperature

• Regulate the engine's operating temperature: By opening and closing in response to specific changes in coolant temperature to keep the engine's temperature within the desired operating range

How a Thermostat Works

• When the engine is cold, the thermostats is normally closed; restricting flow to the radiator allowing the engine to “warm up”
• As the engine warms, the increase in heat causes the wax to melt and expand, pushing against a piston inside a rubber boot
• This forces the piston outward, opening the thermostat so coolant can start to circulate between the engine and radiator
• As heat increases, the thermostat continues to open until engine cooling requirements are satisfied
• If the temperature of the circulating coolant begins to drop, the wax element contracts; allowing spring tension to close the thermostat, which decreases coolant flow through the radiator

Thermostat Temperatures

• Thermostats have a “rated” temperature such as 180F or 195F
• This is the temperature the thermostat will start to open, give or take 3 degrees
• The thermostat fully open about 15-20 degrees above its rated temperature
• Many thermostats have a “jiggle pin” or “check valve” that allows trapped air in the cooling system to pass through the thermostat and be released from the system.
• If a Stant thermostat does not have a jiggle pin, it will have a "bleed notch” or other method of removing air from the system.

 

[steve340]

What I learned at trade school is that an engine has a coolant bypass system to allow the thermostat to be closed but allow the radiator water to warm slightly so the engine is not thermally shocked (throwing water on a hot metal plate) which results in rapid engine cooling and possible cracking of iron when the thermostat opens.
It also would be the reason the thermostat cracks open at first as stated in Ranger16 post.

I have checked them in a pot of water and they do open like the Stant info says - they crack open and if you keep them in the hot water they "accelerate" to fully open. Even fully open the gap is only about 2 mm or so. Hey they seem to work fine anyway - the gap looks like "can that be enough" but it is.

 

[toolmanmike]

What I learned at trade school is that an engine has a coolant bypass system to allow the thermostat to be closed but allow the radiator water to warm slightly so the engine is not thermally shocked (throwing water on a hot metal plate) which results in rapid engine cooling and possible cracking of iron when the thermostat opens.
It also would be the reason the thermostat cracks open at first as stated in Ranger16 post.

I have checked them in a pot of water and they do open like the Stant info says - they crack open and if you keep them in the hot water they "accelerate" to fully open. Even fully open the gap is only about 2 mm or so. Hey they seem to work fine anyway - the gap looks like "can that be enough" but it is.

And it needs to be said, if the coolant flows through the radiator too fast the heat won't be removed. The thermostat regulates that flow so the radiator can do it's job.