Thermostat Help

[mckinnon45]

Hey all, I have a 78 New Yorker with a 440. I was looking around for a thermostat, and noticed there are 160, 180, and 195 degree thermostats...I was going to get the 160.

Then I noticed that there are OE Temperature thermos and Alternate Temp Thermos...

I've googled around, but never really found a good answer. Can someone tell me what the difference is?

I am on rockauto if that matters.
http://www.rockauto.com/catalog/raf...2200&partkey=48778&a=FRc1065619k48778-2911777

Thanks!!!

 

[commando1]

OEM was 195. Modern motor oils work best at 195 and is best for the engine.
If you have sometimes had the temp. run too hot, go 180. The system is 34 years old after all.
Here in FL where I idle with the A/C on and it hits 95 degrees, I have to run 160 to keep it out of the danger zone in July and August.

 

[C-440-300]

Commando1,
You bring up a point that always confused me. My understanding of Tstats is that it's the temp that "starts" the flow to the radiator in increasing temps, and "stops" in decreasing temps to prevent inefficient operation (and dangerous for lubrication). I have never known the Tstat to zero in on a selected temp, except when crossing through either of these points.

If your cooling system cannot take enough heat away from the engine, your temp will rise to the system's ability(inability - Peter Principle ). The Tstat will not lower or raise the engine's cooling capacity per se.

For my iron block/iron head engine ('66-300-440), the ideal temp for power and moisture burn off of crankcase oil, is around 190. I can feel the power loss above the 200 degree side.

I have never heard of anyone using a Tstat temp of 160, as an extreme example, to make an engine cooler. If I am not mistaken, it is only the temp that the engine is allowed to warm up to before the cooling circuit is enabled...

?
Thank you.

 

[C-440-300]

Then I noticed that there are OE Temperature thermos and Alternate Temp Thermos...

Thanks!!!

mckinnon45,
Can you find a 190? What was the FSM value recommendation at the time? Do you still have the pollution control paraphernalia on it? If I remember, EPA mandates required some engine operations to increase Tstats settings. My '66-300-440 was supposed to be 180, but I don't have much pollution stuff (no EGR - which can cool engine a bit, actually); only a PCV/breather combo.
I do not have access to your service manual...

 

[commando1]

What was the FSM value recommendation at the time?

Da FSM for his car sez it's dis:

 

[Newp]

The T-Stat will ''try'' the keep the coolant temp. at what ever it's rating is. ( 160-180-195)
It does that by restricted and unrestricted coolant flow through the thermostat.

 

[Fratzog]

Commando1,

I have never heard of anyone using a Tstat temp of 160, as an extreme example, to make an engine cooler. If I am not mistaken, it is only the temp that the engine is allowed to warm up to before the cooling circuit is enabled...

?
Thank you.

My 68 Monaco 500 has a mild rebuilt 78 440 with a 160 Tstat. I only have the factory guage but before the rebuild it would start to go right and puke after I gave it a good run on the highway. Now no matter what its always left of center. I know its not a fair before and after comparison but I have had no issues i.e. puking with the 160 Tstat.

 

[1978 NYB]

Another cooling problem with 34+ year cars are the radiators.

 

[C-440-300]

The T-Stat will ''try'' the keep the coolant temp. at what ever it's rating is. ( 160-180-195)
It does that by restricted and unrestricted coolant flow through the thermostat.

That's how I understand it, too. If the cooling capacity can only bring the temp down to 195, a 180 Tstat will be wide open all the time. Temp readings will never go below 195 unless the equation changes (cooler air or less heat, etc.)

In my humble experience with other lines of combustion vehicles, changing the original design does not come without consequences...

 

[mckinnon45]

Thanks guys for the information...I guess I should open the manual in my car before pounding the keyboard next time. I ASSumed that 160 would be better since it was cooler...

I'll definitely go with the 195 now! It ran warm 1 time, after sitting in traffic on a warm day, and not really moving. And when I say warm, I mean just barely over the 1/2 way mark on the gauge, where it normally runs on the left side of the 1/2 way mark.

I am going to blow the radiator fins out as soon as I can, to see if anything is in there. When idling warm, it seemed like the fan was pulling a decent amount of air through it, but it never hurts to make sure it's clear.

THanks for all the help guys

 

[Tulkien]

Hi everyone!

I have a question about this as we.
Here my local mán says after 5000Km he wants to put the thermostat in. Have you ever heard of this? How can the motor break in, without a thermostat? I have niw about 1500 Miles in it. It was redone in it almost everything. And he dönt want to put it in, because of the bad quality of them and he afraids that will boil up.
Any suggestion? Thanks!

 

[detmatt]

The thermostat keeps the coolant from being allowed to flow continuously and allows the radiator to do its job. The thermostat is very important as is running the right mix of antifreeze/coolant to water. Get yourself a 180 degrees unit and tell your mechanic to install it.

 

[Tulkien]

Yes, thats clear. The question is when is my engine broke in? After how many miles? And how can an engine break in without thermostat?
Thank you?

 

[68plymouth383]

Welcome to the program! !

 

[detmatt]

You should ALWAYS have a thermostat in place.
I don't recall the stories of averybody who bought these cars new having to come back after 500 miles so that Ma Mopar could install the thermostat. Tell your mechanic he's an idiot.

 

[commando1]

I bet the engine ran hot after he did the work, yanked the thermostat, and gave you that BS story stalling for time.

 

[bajajoaquin]

Going back to the question about how a 160 degree thermostat could affect the overall temp of the engine. I'm going to operate on the assumption that if he said he saw it, it's true, and it happened.

It could be that on a hot day, the cooling capacity is marginal. A thermostat that opens at 160 has a slightly cooler engine compartment, and that few degrees makes the difference between whether the radiator can keep up or not. With a 185 or 190, the engine is hotter, it can't cool that, so it gets hotter still.

 

[commando1]

A thermostat that opens at 160 has a slightly cooler engine compartment, and that few degrees makes the difference between whether the radiator can keep up or not. With a 185 or 190, the engine is hotter, it can't cool that, so it gets hotter still.

Not what my mama dun taut me.
The engine is going to generate the same amount of heat regardless of what temperature the thermostat keeps the coolant at.

 

[bajajoaquin]

Well, then your story about 160 degree thermostat can't be true then.

But my point wasn't that the engine wouldn'tgenerate the same amount of heat. It's about the capacity to shed it. Heat is transferred as a function of three things: The thermal properties of the materials, the temperature differential, and the time allowed to transfer. The thermal properties of the radiator, water, and air don't change with the thermosat, and neither does the time for exchange. However, the temperature differential could change.

Given the example you gave, in a slow-moving car on a hot day, an engine that started to have the cooling cycle at 160 degrees could start out with a cooler engine compartment, and be in a better place to shed heat during a stop-and-go cycle. One that started at 180 or 190 would have a lower temperature differential, and shed less of the heat for every ounce of coolant that passed through.

Do I think it's likely? No. But accepting your story as accurate, I don't have a better explanation for why a 160 degree thermostat made a difference.

Do you?

 

[66/440]

I have always understood that when all components are working properly that the cooling system is capable of removing X number of BTU's. The thermostat works by opening and closing at the temp value indicated. However the cooling is not instantaneous more like the waves in the ocean as the cooling effect rises and falls. If you start with a higher temperature value the system has to work longer cycles to remove the heat and can sometimes be overcome temporarily. By allowing the cooling system a head start ( lower temp value) you can help the system from being overworked.
Conversely a cooling system needs the coolant to dwell in the radiator for heat to be removed, if you do not run a thermostat or restrictor the coolant passes through the radiator too quickly for the maximum amount of heat to be removed.