Thermostat: 160 or 180

[HDowse]

My car has 160 thermostats but I wonder what the rationale is for having the 160 or the 180 that the vendors carry? I tend to think that 180 makes sense, keeps sludge from forming but maybe Henry designed the V8 to run cooler? Would I encourage overheating with the 180? The weather can get hot here in the summer.
Thanks,
Hunt

[petehoovie]

Please correct me if I'm wrong, but given modern detergent oil formulations, I doubt that "sludge" is a serious concern. And no to mention how most of us baby our babies with required/frequent oil changes....

[Lanny]

I would use the 180












.

[krackerjack1951]

thermostats are installed to help keep the coolant in the radiator longer so ram air can maintain an even temp in engine.. 10,000 words have been written about the subject...I run 185 stats in my pumped up merc engine..seems to work best for my application,,,july hot the engine temp remains 185/195 on interstate speeds 70mph.a steady even temp is the most desireable.and not distort the engine design..these engines were designed for 50 mph speeds..when we mash on throttle,more gas to engine generates more heat...raise your right foot..less gas,hence less heat ,,engine cools down.. class dismissed..

[tubman]

160 is too cold for these engines. Run 180's unless you have other problems you don't want to solve in the near future.

[JSeery]

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In the early cars the antifreeze was alcohol based and the hotter the engines the faster it evaporated out. Along with other factors as technology improved Ford raised the recommended operating temperatures. The thermostats do not determine the maximum temperature your engine will run at, they determine how quickly it would get up to a minimum operating temperature and maintain that minimum. Modern oils are much better but engine operating temperature is still a big factor in clearing the moisture out of the oil. Higher temperatures also improve engine lubrication.

[HDowse]

Thanks for the comments, all signs point to changing out to 180’s. This car has signs of sludge (and that rust problem from another post) from being an in town car, short hops, not much long distance travel. I've changed the oil once and when it gets dirty again, no matter the miles, I'll change it again and again. When I got my 1923 T a few years back, I had to run kerosene thru a few times to clean things up. 85 V8’s aren't like a T but it will be good to get the sump flushed out.
Thanks,
Hunt

[Tinker]

i would suspect even if you put a 160 in and did any amount of distance driving, especially stop and go driving, the engine would ultimately get hotter then 160 or 180. Short cruises a 180 might be the best option.

[Old Henry]

Originally Posted by HDowse

I've changed the oil once and when it gets dirty again, no matter the miles, I'll change it again and again.

A sign that detergent oil is doing its job is the darkness of its color. The darkness is actually the contaminants being suspended in the detergent oil until it's drained out rather than letting the contaminants stick to the engine surfaces as sludge. Better to change oil by mileage rather than color. See more here: http://auto.howstuffworks.com/5-engine-oil-myths2.htm

[Drbrown]

I use 160 stats but not concerned since I use 10w-30 oil, change it frequently and do long highway runs.

[TomT/Williamsburg]

In my avatar I initially ran 160s and temps never got above 170 even when at Bonneville but normal op temp was 150-155. Changed out to 180s recently and I still never get above 170 save for the first few minutes until the thermostat opens. Normal op temps are still 150 to 155. I run 20-50, 5 qts, no filter, change it frequently, put in the appropriate amount if zddp additive and the inside of my engine stays very clean and no sludge buildup. Basically it is a stock motor .....

[willowbilly3]

My theory is run an engine as hot as you can and still keep the coolant inside it.

[34PKUP]

Originally Posted by TomT/Williamsburg

In my avatar I initially ran 160s and temps never got above 170 even when at Bonneville but normal op temp was 150-155. Changed out to 180s recently and I still never get above 170 save for the first few minutes until the thermostat opens. Normal op temps are still 150 to 155. I run 20-50, 5 qts, no filter, change it frequently, put in the appropriate amount if zddp additive and the inside of my engine stays very clean and no sludge buildup. Basically it is a stock motor .....

I suppose if I and everyone who has them removed their inner and outer fenders and just had a hood rain cover, they too would have the same or close to the same results. But that is not the real world, just a small portion of it.

[firerod]

I am going to use 180 in my 59a flathead. Anyone have a part number and store(Napa, O,Rielly, Mac's) you have had the best luck with.

[TagMan]

Maybe I'm wrong, but once the thermostat opens up, how would it control engine temperature ? A thermostat, to my knowledge only helps the coolant to warm up to operating temperature faster or slower, depending on its rating in degrees. Once the thermostat is open, it's open - from then on, it depends on the efficiency of the coolant system (i.e. ambient temperature, radiator design & condition, fan design, fan speed, shroud design, etc.).

If I'm wrong, please tell me how an open 160°F thermostat will cool an engine any better than an open 180°F one would. I'm always willing to learn.

[Fordestes]

The 160 degree will open sooner and start the cooling process at a lower temp. Now IF it were possible! the engine could cool down below the opening temp, the thermostat would close or restrict coolant flow and allow the coolant in the block to stabilize and re-open at a designated or set temp thus regulating coolant temps and flow, although a working or (being driven ) engine will heat up in accordance to load ,ambient temp, cooling systems ability to extract heat, oils ability to carry away heat to the oil pan and exhausts ability to dissipate heat , and normally won't see the thermostat opening temp until the vehicle is turned off and allowed to cool, you are correct in your thinking, so the heat retention is what the gauge should show as a operating temp. A hotter thermostat will prolong the coolant being retained in the block and restrict coolant flow until the higher temp is reached and will act in the same manor, that is one reason the heater will be warmer quicker in the winter ,if a cooler thermostat is used the heater may never get up to an acceptable or more comfortable cabin temp ( less restriction) , here in the south we used to restrict air passage through the radiator core to cause the temp to be retained to suit our cabin temp requirements. in the thirties it wasn't unusual to see a ford going down the highway in the summer with one side of the hood propped open to allow faster air intake through the radiator core and less heat retention inside the engine compartment ( better air circulation), on large trucks we had thermostats and shutter systems, as a rule when pulling a grade with a heavy load the shutters would open allowing more air to pass through the radiator, and on a flat land the shutters would almost close off the radiator core to limit the air flow in accordance with the demands set by a temperature regulating device , some had what was called a shutter over ride to open the shutters or increase air flow as desired. It was not uncommon to squash a beer can and block the shutters open , some of the high dollar cars of the same era were equipped with a shutter systems as well. sorry to be long winded but I was using a synopsis to better clarify the understanding.

[51 MERC-CT]

Granted, 180° thermostats may be better for engine efficiency and perhaps someone can post any concrete evidence to reflect that, as it applies to 'flatheads'.
As I recall 160° and 180° thermostats used to be referred to as 'summer' and 'winter'.
The sole purpose for the 180° was to increase the heater temperature.

[jake197000]

modern cars can and do sludge up.people go way to far on there oil.if u tell them 5 k they go 8.we see it all the time.do not follow the oil change lite on your car if u plan on keeping it a long time.lab test be damned.