What degree Thermostat?

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68CUDA/6VERT

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What degree thermostat are you using in your Slant 6? I am changing my
water pump and thermostat and it seems that 195 was original to the car. I was going to go with a 180. Besides the 15 deg -- what is the benefit or pitfall
of running a 180 vs the 195?
 
i used a 180 in my slant, but i also pulled a 195 out of it. the only difference i know of is that it lets the engine run hotter/cooler . but im no thermostat guru lol
 
The benefit is lower engine and engine compartment temps. The benefit of the compartment temps is obvious.....easier on wiring, hoses, plastic, etc. The benefit of lower engine temps is less likelyhood of a cracked exhaust manifold or vaporlock and a running temp father from an overheat temp....it just gives you a little more cushion under extreme conditions or if you have a sudden cooling problem out on the road. The only benefits of the higher temp thermostat that I can think of offhand is lower smog emissions and a higher output heater.
 
The thermostat ain't gotta thing to do with how hot the engine runs. Just sayin.
 
How do you figure that? With a 160 degree one, it won't even get up the operating temperature. If one is stuck or missiing, the engine can overheat. Why do you think they used one?
 
On this same line any suggestion for a good replacement aluminum radiator? Preferably larger then the current?
 
The thermostat has basically one purpose. For quicker engine warmup. Once it's open, it's open. You think it's gonna close again with the engine running? No, because it sees coolant above the marked temperature on the engine side of the thermostat the whole time the engine is running after warmup. All the thermostat does is regulate flow to warm the engine up. Period. It's the radiator's and all accompanying accessories such as the fan, shroud and water pump that KEEP the engine cool, NOT the thermostat.
 
I've got a 170 thermostat in my slant and it gets to operating temp pretty quick and sits on about 90c on the open road doing 110 kmh.I'm happy with that.
 
a good radiator and clutch fan do a great job. if you can afford a rebuilt radiator i'd do it now when you change the pump. they build up lots of crud in the tubes over the years.
 
180° is factory equipment and best choice for slant-6s through '73 (some years had 185° or 190°), then they went to 195° through the end of production. Best pick depends on your underhood configuration, ambient temperatures and vehicle usage patterns, the fuel you have available locally, and the kind of coolant you're running. Colder than a 180° stat, or no thermostat, is not a wise choice.

Best thermostat is a Stant SuperStat, 45358 for 180° or 45359 for 195°.

Premium radiator? Sure, see here.

Reading between the lines, it sounds like you might be trying to chase down an overheating problem…?
 
First, I don't agree with StrokerScamp's description, and I am sure others would agree that the thermostat's function is the regulate the water temperature leaving the engine at close its temperature rating, though the exact controlled temperature varies with the thermal load (lookup "proportional offset").

I recently changed the thermostat in my 64 Dart 225 because I wanted a 195 F thermostat. I found it already had a 195 F thermostat installed. Indeed, rockauto listed that as the standard temp, which surprised me since I thought factory was 180 F in those years. The higher temp was certainly standard in the 80's slant six. It reduces emissions and gives more mileage, at the loss of a little horsepower at WOT due to the less dense intake air and slightly more propensity for spark knock. I doubt a 195 F thermostat would exacerbate over-heating since by the time the cap vents it should be fully open anyway, and we can all agree with StrokerScamp that when the thermostat is full open it doesn't matter whether it is marked 180 F or 195 F.
 
I found it already had a 195 F thermostat installed. Indeed, rockauto listed that as the standard temp, which surprised me since I thought factory was 180 F in those years.

It was. The catalog is wrong.

The higher temp was certainly standard in the 80's slant six. It reduces emissions and gives more mileage, at the loss of a little horsepower at WOT due to the less dense intake air and slightly more propensity for spark knock.

The major downside of a 195° thermostat is the nuisances caused by hot-soaking a carbureted fuel system. If you live somewhere cold, or if your fuel doesn't contain dethanol, this probably won't be a major issue.

I doubt a 195 F thermostat would exacerbate over-heating

Right. A 195° thermostat won't cause overheating, though a temperature gauge calibrated to read centre-normal with a 180° thermostat will read higher than some drivers might be comfortable with if a 195°*thermostat is installed.
 
i run 160 in my slant and my 360 never had any problems

It's like smoking: you won't notice any problems now or next week or next year, but eventually the gradual damage will make itself apparent. With your too-cold thermostat you're throwing away gasoline money and causing unnecessarily rapid engine wear.
 
Thanks guys -- I guess 180 is going back in. That is what I was thinking originally. My radiator has already been done- so I am not trying to fix an overheat problem. I have a small leak from the pump and the hoses need replaced. I might as well replace everything at once (pump, stat, and hoses) so that it is done and hopefully trouble free for some time.
 
Look at cylinder wear to temp graph, the line goes almost flat after about 180, which they say is the optimum temp for longevity and combustion. 160 is too cold from a few sources.
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The thermostat has basically one purpose. For quicker engine warmup. Once it's open, it's open. You think it's gonna close again with the engine running? No, because it sees coolant above the marked temperature on the engine side of the thermostat the whole time the engine is running after warmup. All the thermostat does is regulate flow to warm the engine up. Period. It's the radiator's and all accompanying accessories such as the fan, shroud and water pump that KEEP the engine cool, NOT the thermostat.
I disagree. The warm-up part of it's function is important....sure.....but the regulation of water flow is more important and the main function of the part. A thermostat will close while the engine is running if the heat produced in the engine is less than what the cooling system is shedding. Take going down a long hill, the engine is producing very little heat but the cooling system is still dumping heat. Once the coolant has lost enough heat, the thermostat will close at it's built in temp and restrict the water flow so the engine operation temp stays up where it should be. Once you hit the bottom of the hill, you'll step on the gas and produce more heat and the thermostat will open again and allow more flow so the radiator can shed more heat. This assumes all the components are working correctly and there are no internal engine problems (like thin cylinder walls) that can overwhelm the system. Running an engine with a 195 stat is fine.....for the engine. It's everything else in the engine compartment that's taking the hit. At 180, It's still running efficiently and easier on everything else. At 160, it's just not hot enough for mileage, power, heater performance, or anything else.
 
A thermostat that is used in automobiles uses an internal combustion engine to regulate the flow of the coolant. When the thermostat is open, the coolant passes through the cylinder head where it looses the heat the air that flows through it. A water pump that is driven from the engine will propel the coolant around the system. When the thermostat is closed the flow is then prevented and the engine is then allowed to heat up to its optimum temperature. The thermostat is constantly opening and closing during operation to maintain the normal operating temperature of the engine. if an engine has a 180* thermostat, once the engine coolant has reached 180* inside the block, the thermostat opens to let cool water in to keep the engine in the 180* range. once the engine has cooled to below 180*, the thermostat closes to get the temperature back up to 180*. a thermostat is continually opening and closing to maintain temperatures in the 180* range. same goes with any 160* 170* 195* .a thermostat has every thing to do with how hot or cool an engine runs. the radiator and fan are the parts that do all cooling so when the thermostat opens, it has cool water to let in the engine.
 
Some people forget (or just don't know) that a thermostat controls the minimum operating temperature NOT the maximum operating temperature.

I love Dan's post and it is a great reply to all those "I have been running "X" part and never had any problems". Sometimes you never do see the problem but when you are rebuilding your engine at 85,000 miles and your buddy, with the same engine build, is refreshing his at 180,000 miles, that 160 stat could be the cause.

"It's like smoking: you won't notice any problems now or next week or next year, but eventually the gradual damage will make itself apparent. With your too-cold thermostat you're throwing away gasoline money and causing unnecessarily rapid engine wear."
 
You mean you can tell the difference (and the 160 feels better) just driving down the road? :)
 
Go ahead, it's your car and you can do anything you want.

But in a thread like this, one that may be found with the "search" function, it is in everyones best interest to give helpful and useful information.

not giving info just stating what i run and have for years
 
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