180 or 195 thermostat?

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I have a 04 impala with the 3.8L. I am going to be changing the thermostat on it along with some other maintenance I am going to be doing. While looking for a thermostat I found they come in 180 degree and 195 degree. What is the benefit of either of them? I assume the 180 will open up quicker so it means it will take longer to get up to operating temp? Anyone know what the stock thermostat is in an 04 impala 3.8L? Also if it matters I am in WI with cold winters.

Thanks
 
I do not know of any car that uses less than a 190 degree thermostat for original equipment.

Benefits of a 180 degree thermostat: well, few... perhaps if your car overheats a lot, or has been modified for much more power you could benefit. Remember, at 210 degrees or more, they are both wide open, so neither will be better going across death valley. But the 180 degree thermostat would give you an engine 10 degrees cooler at the bottom of a long hill, that may help if you are towing a heavy load with a marginal cooling system.

Benefits of 192 degree: Better mileage, much better heater output in the winter, oil temperatures rise high enough to boil out excess fuel and moisture in the winter.

I believe Ford lead the parade to the 192 degree thermostat in about 1965, at the time the development studies - that they published in the SAE journal - showed that oil dilution with fuel and water was greatly reduced by going up to 192 degrees... their controlled wear tests indicated that engine life may increase by 30 percent for those using cars for lots of winter short trips. This is about the time Ford was shocking everyone with their recommended 6,000 mile oil change, and they felt the 192 degree thermostat was an important component of the longer oil changes.

Sorry to get so long, sometimes my keyboard just takes off!!

fsskier
 
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The stock is probably 195 for the 3.8L, so they are offering a colder stat as is possible to get with most engines. Other than racing applications, there are generally no benefits to a colder thermostat unless you are trying to deal with a specific problem. Since you haven't mentioned any temperature issues with this engine, the stock thermostat would be the best choice, imho.
 
They should both limit the coolant flow until the temperature they are rated for is reached.

Personaly, I like to use 180 if there is any chance that the cooling system might have some buildup clogs from years of use.

A cooler thermostat will give less MPGs, but also gives a little better cooling safety margin when you load the cooling system on hot days with the AC on.
 
Since you are in Wisconsin, let me add an additional note: In 1965 I was commuting with a 59 Ford 6 stick.... a decent combination, but I was always looking for improvements. College days, work nights, off at 1 am, always cold half way home... I learned of the 192 degree thermostat - I had a 180 in at the time , bought one and put it in. I was expecting that it would be difficult to tell the difference but WOW... the heater went from warm to HOT.

People in Florida might not care, but Badgers (Wisconsin) certainly do!!
 
If your engine calls for 180, then go with 180. If it calls for 195F, then run 195F.

Deviating away from the factory thermostat on computer controlled OBD-II engines will cause drivability problems, or even engine troubles down the road.

Q.
 
The 180* thermostat is for preventing the nylon upper intake manifold and lower intake manifold gaskets from disintegrating as quickly on the 3800 Series II. It's also a very slight performance modification. I've had a 180* thermostat in my Buick to keep the upper intake manifold happy for 70k miles with no reduction in heater capacity or any other negative effects. It warms up quickly, gets good fuel mileage, and is a little bit of added protection for the upper intake.

Both versions got the 195* thermostat.

Not recommending one either way. It's up to the OP to decide which way go go.
 
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Originally Posted By: fsskier
I do not know of any car that uses less than a 190 degree thermostat for original equipment.


Many Asian engines actually use a 180*F thermostat as OEM. My Camry does, and my Corolla did. Heck, my Acura MDX with the J35 engine and old Nissan truck with the KA24E actually use a 170*F thermostat.

Most vehicles with outlet-side thermostats (many domestics still use this) use 195*F thermostats. Many newer engine designs use inlet-side thermostats, which typically run at a cooler temperature.
 
I'd stick with the OE temperature stat.
I'd also buy the best stat I could find because if it's anything like my Buicks 3.1, it's a PITA to change.
 
Use whatever came in the car when new. Running too cool is bad for all kinds of reasons (efficiency, fuel dilution, fuel efficiency, wear, emissions etc...) and it won't actually do anything to solve an actual problem if you are overheating.

Modern engines are designed to run hotter. Even late 90s/early 2000s BMW V8s (i.e. not all that new) use 226F thermostats. This creates a high amount of system pressure which results in some long term plastic longevity challenges but assuming the fan system is working correctly the system has no trouble keeping temperatures under control in hot stop and go plus AC conditions even starting at 226F.
 
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You are unlikely to find ANY OBDII vehicle with less than a 195 as stock.

Unless you're tuning for power hotter is better. Period.

And the hotter it is the easier it is to maintain that temp, as the differential temp makes it easier to give up the heat.
 
Originally Posted By: Hokiefyd
Originally Posted By: fsskier
I do not know of any car that uses less than a 190 degree thermostat for original equipment.


Many Asian engines actually use a 180*F thermostat as OEM. My Camry does, and my Corolla did. Heck, my Acura MDX with the J35 engine and old Nissan truck with the KA24E actually use a 170*F thermostat.

Most vehicles with outlet-side thermostats (many domestics still use this) use 195*F thermostats. Many newer engine designs use inlet-side thermostats, which typically run at a cooler temperature.


My stock thermostat is a 186*/187*.
Not much difference to a 190/195/197 I know, but it is still under 190*.
wink.gif


I have 186/187* stock, 180* and 160* t-stats to choose from. I might try a 180* MotoRad this summer (with subsequent high/low fan settings reprogrammed, of course) when I change/flush out the Death Cool and install new silicone hoses.
 
Originally Posted By: SteveSRT8
You are unlikely to find ANY OBDII vehicle with less than a 195 as stock.


As noted above, plenty of OBD-II engines use thermostats colder than 195*F.
 
Originally Posted By: Hokiefyd
Originally Posted By: SteveSRT8
You are unlikely to find ANY OBDII vehicle with less than a 195 as stock.


As noted above, plenty of OBD-II engines use thermostats colder than 195*F.

You're correct, the OEM thermostat of my E430 is 87C = 188F.
 
Originally Posted By: SteveSRT8
Sorry, my bad. I meant domestic vehicles.

That 2000 Z28 shipped with a 195.


If that is the case, then why can I not buy a thermostat with that temp rating today??
 
Originally Posted By: dailydriver
Originally Posted By: SteveSRT8
Sorry, my bad. I meant domestic vehicles.

That 2000 Z28 shipped with a 195.


If that is the case, then why can I not buy a thermostat with that temp rating today??


Have you looked at every local autoparts website? Pepboys, Advance, Autozones etc etc. Look for all offered(OEM temp and non-OEM) and see if you can find any they claim to fit your vehicle. Try checking RockAuto as well. Not familiar with your car, though. The dealer won't have it?
 
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