Petersubaru Posted November 26, 2007 Share Posted November 26, 2007 does anybody have any opinions on useing their 160deg.(stock 170deg) thermostat for the stock N/A 2.5L....I can appreciate the "fail-safe" operation of the unit and haveing a cooler running motor in the hot summer days..but in a colder climate (10below) would I get enough heat into the cabin Quote Link to comment Share on other sites More sharing options...
nipper Posted November 27, 2007 Share Posted November 27, 2007 does anybody have any opinions on useing their 160deg.(stock 170deg) thermostat for the stock N/A 2.5L....I can appreciate the "fail-safe" operation of the unit and haveing a cooler running motor in the hot summer days..but in a colder climate (10below) would I get enough heat into the cabin NO. The engine is designed to run optimally at 180 degrees. You will never have an effeciently running engine at 170. Yes 10 degrees can make a big difference to the engine computer. If your going to race, and worried about temp, get an external engine oil cooler to help manage heat. ALso a fresh radiator will help tremendously. nipper Quote Link to comment Share on other sites More sharing options...
Petersubaru Posted November 27, 2007 Author Share Posted November 27, 2007 NO. The engine is designed to run optimally at 180 degrees. You will never have an effeciently running engine at 170. Yes 10 degrees can make a big difference to the engine computer. If your going to race, and worried about temp, get an external engine oil cooler to help manage heat. ALso a fresh radiator will help tremendously. nipper My thinking is somewhat along the same lines as to what you have said..somewhere they have said that their Thermostat opens above the temp the ECU switches out of the warm-up mode, but most of their users are turboed motors..and my thermostat for the 01 outback reads 172deg which I think is fully opened Quote Link to comment Share on other sites More sharing options...
nipper Posted November 27, 2007 Share Posted November 27, 2007 My thinking is somewhat along the same lines as to what you have said..somewhere they have said that their Thermostat opens above the temp the ECU switches out of the warm-up mode, but most of their users are turboed motors..and my thermostat for the 01 outback reads 172deg which I think is fully opened I dont remeber if the temp posted is full open or starts to open. I can tell you when its 20 degrees outside the engine temp is 175 and i have plenty of heat. I dont remeber the shift from open loop, to closed loop, but its less then 180 (now that i think about it). It may be 170. Now if you use a 170 temp T-stat, in cooler cold weather, or on the highway, you may dip below that threshold. http://endwrench.com/images/pdfs/OBDSpring02.pdf The threshold for closed loop is 158 degrees. In cold weather you will not reach that threshold. nipper Quote Link to comment Share on other sites More sharing options...
porcupine73 Posted November 27, 2007 Share Posted November 27, 2007 Yes, and despite their 'fail open' failure mode, I have seen posts where they fail closed anyway. A lower temp thermostat is only going to help and even then _maybe_ in consistent high load situations. Go with a Subaru OEM thermostat from a dealer; they can't be beat. Quote Link to comment Share on other sites More sharing options...
Petersubaru Posted November 27, 2007 Author Share Posted November 27, 2007 Yes, and despite their 'fail open' failure mode, I have seen posts where they fail closed anyway. A lower temp thermostat is only going to help and even then _maybe_ in consistent high load situations. Go with a Subaru OEM thermostat from a dealer; they can't be beat. ..I agree..it does not matter if you are looking at Subaru or VW or GM..the OE T-stats are always more heavy duty etc... Quote Link to comment Share on other sites More sharing options...
bulwnkl Posted November 27, 2007 Share Posted November 27, 2007 Would anyone care to explain to me why it is thought that a colder thermostat is good for cooling system efficiency? I can see doing it if your cooling system is inadequate to the task, but you only need 1/4 mile of cooling or something. Otherwise, however, the thermostat has almost nothing to do with the cooling system's capacity except in a harmful way. The size and area of the radiator, airflow, and so on are the things which determine how much heat you can move. If anything, a cooler thermostat decreases cooling system efficiency because the lower coolant temp decreases the temp difference between the radiator and ambient air, thus making the radiator less efficient/effective. It also generally decreases engine efficiency. In any event, I'd suggest sticking with OEM thermostats in most import automotive applications, especially Subaru. BTW, the temp listed for a thermostat is the temp it's trying to maintain, meaning that's approximately opening temp. Quote Link to comment Share on other sites More sharing options...
nipper Posted November 27, 2007 Share Posted November 27, 2007 It's old school thining. Back in the day before emissions and fuel injection, 160-170 was considered a summer thermostat, and 180-190 a winter thermostat. If you lived in death valley, you used the cooler one, since the ability of the car to rid itself of excess heat is greatly reduced. It really doent apply anymore. nipper Quote Link to comment Share on other sites More sharing options...
Petersubaru Posted November 27, 2007 Author Share Posted November 27, 2007 Would anyone care to explain to me why it is thought that a colder thermostat is good for cooling system efficiency? I can see doing it if your cooling system is inadequate to the task, but you only need 1/4 mile of cooling or something. Otherwise, however, the thermostat has almost nothing to do with the cooling system's capacity except in a harmful way. The size and area of the radiator, airflow, and so on are the things which determine how much heat you can move. If anything, a cooler thermostat decreases cooling system efficiency because the lower coolant temp decreases the temp difference between the radiator and ambient air, thus making the radiator less efficient/effective. It also generally decreases engine efficiency. In any event, I'd suggest sticking with OEM thermostats in most import automotive applications, especially Subaru. BTW, the temp listed for a thermostat is the temp it's trying to maintain, meaning that's approximately opening temp. ...I certainly can't answer your question...but if you "google" Crucial raceing and click on products, then again on "coolsafe" ..there is a write-up that got me thinking ...I know with the old carbed suby I have a 180deg "T" (stock 192deg) and some colder plugs will keep the pinging at bay and possibly less expansion between the head and block..just maybe the headgasket will last longer (just some laymans thoughts here) Quote Link to comment Share on other sites More sharing options...
ericem Posted November 27, 2007 Share Posted November 27, 2007 Hmm, so I guess if your not using a OEM thermostat you would loose power? I am using those no name Napa ones. Guess I better get a OEM one. Quote Link to comment Share on other sites More sharing options...
Reveeen Posted November 27, 2007 Share Posted November 27, 2007 It seems to me: That usually the operating temperature of an engine, providing the cooling system is in decent shape, is 10 degrees above the thermostat rating. (eg. 170= operating temperature of 180) @160, or an operating temp of 170 degrees, I find in colder climates, 170 degrees is not warm enough to "heat out" condensation in your engine, meaning I find the oil gets water (or moisture) contaminated in short order (or what I call "the greys"). You can seem to get away with it in summer, but not in winter. Quote Link to comment Share on other sites More sharing options...
nipper Posted November 27, 2007 Share Posted November 27, 2007 Guess I better get a OEM one. Always use a subaru T stat. Aftermarket do not flow as well, and the sometimes dont have the bleed port. nipper Quote Link to comment Share on other sites More sharing options...
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