Thermostat or not

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Fishthatkills

Fishthatkills

Fish that kills
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I have a stock 273 running a 195* thermostat. It runs fine but after a while in the Texas heat it creeps up in temp on the stock guage to 3/4 towards HOT.

My question is since I have bypassed the heater core and live in the heat belt should I run a 180* thermostat or none at all? Pros and cons would be helpfull. I don't want to overheat the motor.

All new hoses and water pump by the way, Stock fan and shroud. As long as I am not running in the heat of the day she runs in the middle to less than middle of the stock guage.

John B.
 
A thermostat is an important part of your cooling system (some people only associate it with the heater and this is incorrect). You may overheat without one.

I would slap in a 180 but it may or may not change anything.

When is your car getting warm? Steady cruise over 45mph or sitting in traffic?
 
I'd put an aftermarket gauge in it so you can tell exactly how hot it is getting. If it gets hot going down the road, 35mph or faster, your radiator is probably partially plugged or just not adequate. If it gets hot when sitting, then it is probably airflow issues, may need a better fan or shroud. as was stated above, 180 t-stat may or may not help.

First thing, get a gauge that tells the temp, not just hot and cold.
 
I agree, My 66 factory temp gage jumped up past half and I could still lay my hand on the valve cover's, they can be deceiving
 
The thermostat controls the flow of coolant through the system. Without a thermostat, the coolant doesn't stay in the block long enough to absorb heat. The same thing happens in the radiator, If the liquid goes through too fast it doesn't have a chance to dissipate heat. A 180 degree stat should do the trick as long as your system is in good condition. I wouldn't be too concerned about higher temps as long as you know what your gauge is telling you. 190-220 is on the hot side but not overheating. If your gauge is running in the red and blowing coolant out definitely a problem. Like Memike said, put a manual gauge on it to see where you're at. Water boils @ 212 coolant boils @ over 220.
15 pounds of system pressure raises the boiling point 45 degrees so you won't have a boiling over problem until 257 or so. Once you figure how truthful your gauge is, you can switch stats or a different fan,shroud, electric fan, or a new radiator like the guys mentioned. toolman
 
I have a 180 in my Dart but since I turned on the fans full time it doesn't get over 185 and that's on a hot day.
 
No stat is another OLD trick that has proven itself not to work. A stat like others have stated allows the coolant to stay in the block to absorb heat, and stay in the rad to cool it, it is a regulator to the speed of the circulation of the coolant. No stat will kill you on startup as your motor will be cold for a longer time,causing more cylinder wear, and itll most likely get hotter than no stat because the coolant is not in either side of the stat to do any good efficiantly. Run a 180. Ideal temp for wear and performance on a carbed motor.
 
Thanks for all of the advise. My Rad is flowing as it should. It does stay in the normal range when driving and it has not over heated or blown any coolant. I guess I will install a (real temp guage) and see what is up! Here is the thing though. It did not do this before I installed the thermostat last July? Before I had no thermostat and it ran in the warm or slightly left of center. I will check the temp though!
 
Question... Does it run perfect early, then spark rattle under load after warmed up ?
If so, pony up for a new radiater. I had the very same problem with a 67 years ago. If caught in a traffic jamb, you'll overheat it. Been there done that. I even used the heater fan to try and cool the water. The final straw for me was leaving a concert. Boiled over before We could get to the open road. The most expensive part of the cooling system so naturally the last thing replaced. LOL
 
Never trust a 40 year old gauge. Get a non contact thermal temp gun and verify the actual temp it is running. My Cuda is an example of how far gauges can be off. When the temp is 180 degrees the gauge is all the way over on the lat line. I tried a new sender and still shows the same so the factory dash gauge is just wacko. And I agree with the guys that a thermostat is needed.
 
Update on thermostat! Ran the car on Fathers day across town to a show. Arrive at 8am no worries. Left at 5pm air temp was 98 and humidity was around 60 to 70%. Car ran in the middle of the guage all the way. Never got over that. Not a lot of stop and go hit only two lights all the way home, about 7 miles.

I tested my fan clutch. I have the viscous type. It should free wheel when cold and hard to turn when warmed up to temp, Right? Well it turns pretty easy when at operating temp so I think I need a new one. It's as far as I can tell a stock fan steel center and aluminum blades rivited to the center section. 7 blades as this is/was an AC car.

Are the viscous fan clutches available. Is there an alternate to the clutch?
I am thinking going to a 180* thermostat and a working clutch would cure my issue.

John B.
 
Most of the time running without a thermostat will actually run hotter for the reasons mentioned above but sometimes you get lucky and it works ok. Nevertheless aa thermostat will make the temp more stable.

In my opinion the thermostatic fan clutch type is the best. But of course it costs more. If I'm not mistaken (somebody correct me if I'm wrong) the thermostatically controlled viscous fan gets harder to turn as the engine gets hot but the non-thermostatic controlled viscous type pretty much remains the same force to turn it no matter what temp they are. That's the reason for the thermostat on some viscous fans, to make it engage better as it gets hot and have less drag on the engine when it's cold. At least that's my understanding of them.

I couldn't get the NAPA link to work so I can't comment on it. Summit and JEGS sells all types of replacement fan clutches. I bought one last year from Summit.
 
One way to test if your clutch is toast (I've heard) is to watch while someone else shuts down the car. If it keeps spinning at all after the motor is off...its bad. If it stops right when it should...it's ok.

Also, a 195 is a little bit of a hot stat (IMO). I'd test your clutch to make sure it's spinning your fan correctly, and put a 180 in....you dont need your motor to warm up to 195 before opening and allowing the coolant to flow for any reason, so I'd switch to a 180.

Oh and yes run a stat...and get a good temp gauge to see exactly what your running at!
 
The fan clutches are oil filled. If the oil is leaking out or if you can move the blade more then 1/8 inch forward and back, replace it.
 
I can spin it when cold and it moves freely when hot. It does not free wheel when hot. I think the clutch and termostat are my cause of the heating trouble. Won't have the time to replace them until this weekend. I will let ya'll know how it goes.

John B.
 
Most people do not understand that a thermostat's job is to make sure your engine does not run too cool. It impedes water-flow until the temperature of the engine is at the correct running temperature.

If you run without a thermostat and you have no other cooling issues then your engine will run too cool and not be efficient. This is not a good idea.
 
Fishthatkills said:
I have a stock 273 running a 195* thermostat. It runs fine but after a while in the Texas heat it creeps up in temp on the stock guage to 3/4 towards HOT.

My question is since I have bypassed the heater core and live in the heat belt should I run a 180* thermostat or none at all? Pros and cons would be helpfull. I don't want to overheat the motor.

All new hoses and water pump by the way, Stock fan and shroud. As long as I am not running in the heat of the day she runs in the middle to less than middle of the stock guage.

John B.
Click to expand...
I run a 160 degree thermostat....and a Chevy HHR fan.....what do you think about that?
 
Fishthatkills said:
I can spin it when cold and it moves freely when hot. It does not free wheel when hot. I think the clutch and termostat are my cause of the heating trouble. Won't have the time to replace them until this weekend. I will let ya'll know how it goes.

John B.
Click to expand...
Look at getting a heavy duty thermal clutch for your fan and it should spin with some resistance even when it is cold...I got mine for about $50 bucks at O'Riellys
 
A friend of mine has a warmed over 360 on his 76 Duster. 9,8 compression. He's got high temp since he replaced his old 318. He lives on a very hot region. His engine is knocking under heavy acceleration.. He took off his thermostat and put a restriction on the bypass that goes from the water pump to the intake. He says he's seen many 360 without the bypass. Is it a good idea to eliminate the bypass for a 360 "living" on a very hot region? Thanks for your answers.

Ricardo.
 
popular beleif is that if you run a lower temp thermostat that your engine will run cooler. That is incorrect because the thermostat opens at a lower temperature, thereby not allowing the coolant in the radiator to fully cool.

Example 195 to a 180 may have a few minutes difference in the opening time, the coolant is now in the radiator a few less minutes, causing it not to cool as much before it enters the engine.

If you want your engine to run cooler, the coolant, either needs more time in the radiator or a larger core radiator.

Also older gauges are not as accurate, either because of age or analog, I would not trust an older gauge.
Have you checked it with an IR temp gun? This will help tell the real temperature of your engine, at inlet of thermostat, intake, heads, or exhaust, just about anywhere you check with it.
 
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