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Why you should use OEM parts for some stuff...


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Check out the differences between these thermostat's. The one on the left came from the dealership, and came with a cool rubberized metal gasket, the one of the right came from Autozone I think. They are both rated at 192 degrees....

 

The one of the dealer is obviously going to flow quite a bit better, and the construction quality difference is just amazing. The dealership one cost me ~ $12. Can't remember what the Autozone one cost, but even if it was $1, I would still go to the dealer for this one....

 

After replacement, the temp is much more stable. Still about the same on the low end, but the OEM one keeps the needle in the same spot no matter what. I can be idleing or cruising at 80, and it's still in the same spot on the guage. With the aftermarket one (which is not that old, and certainly not bad), the guage would fluctuate quite a bit between idleing or cruising. Cruise was fine, but idle would heat up a little much for my liking - especially with summer comming very shortly.

 

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The problem with the OEM thermostats is that they are only available with the 195 degree temp. My turbo car runs to hot to use the OEM and it has a double row radiator. I use the 180 degree stant brand, and will be switching to the 170 degree after I reseal my motor.

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If your turbo runs hot, then your turbo needs fixin, not a band-aid like lower temp thermostats, and double row radiators. Ask yourself this: "did it overheat when it was driven off the showroom floor?". My guess - probably not. Besides that, the OEM 195 if it's anything like the EA81's you see above probably flows better than an aftermarket 180. But if you are going to do it, at least look at ALL the aftermarket ones you can find and pick the best. Maybe find out who OEM's the subaru ones, and see if they make other temps in the same size. But if I were you, I would be looking to figure out what is causeing you to need more and more cooling system as the engine ages. Band-aids like that will only result in cracked heads, and blown headgaskets if left unchecked.

 

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Lots of stuff can make the engine warmer - bad EGR for example will increase combustion temps. Low oil pressure will cause the oil to not remove as much heat. Incorrect coolant mixture will reduce cooling ability (no - you should NOT run 50/50 in CA). Clogged passages in the block and heads. Cracks in the heads that allow combustion gasses into the coolant (small cracks might not be noticed, but can cause overheating and a slow loss of coolant). Any small leak into the cooling system that causes it to not fully pressureize. Another big one is aftermarket parts that aren't up to snuff. Water pumps with stamped impellers instead of forged impellers like the stock ones. Crappy small thermostats.... etc, etc. Also the guages are not known to be totally accurate, and the sending units go on the blink now and again. A full system check with independant sensors is in order.

 

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i agree completely, but, some parts guy handed you the wrong one. i've never seen one with a lip around the outer edge. i run a $3.50 thermostat from fleetfarm, and it works great. if theres a book there, use it yourself, having some dood look it up for you is asking for trouble.

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Pretty sure I wasn't given the wrong one. The "lip" is just the way it was constructed - it fits in there just fine, has the right temp rating, and has the jiggle pin. Even came with the correct gasket, so I must conclude that it was indeed intended for my application. It's just crappily designed, and made as cheap as possible. Like I said - it worked, but not as well as I wanted it to.

 

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If your turbo runs hot, then your turbo needs fixin, not a band-aid like lower temp thermostats, and double row radiators. Ask yourself this: "did it overheat when it was driven off the showroom floor?". My guess - probably not. Besides that, the OEM 195 if it's anything like the EA81's you see above probably flows better than an aftermarket 180. But if you are going to do it, at least look at ALL the aftermarket ones you can find and pick the best. Maybe find out who OEM's the subaru ones, and see if they make other temps in the same size. But if I were you, I would be looking to figure out what is causeing you to need more and more cooling system as the engine ages. Band-aids like that will only result in cracked heads, and blown headgaskets if left unchecked.

FYI, my car does not overheat with the OEM thermostat. It runs at 3/4 (maybe a little less) on the cooling guage. With a 180 degree stat, my car stays at halfway on the guage. After I reseal my engine, I plan to increase the boost, so I will replace the 180 with a 170. Because Subaru heads crack so easily, I consider hot to be anything above the half way point on the temp guage. (It would have been nice if Subaru put a few numbers on the temp guage.)

 

My cooling system is as perfect as could be. It has a new OEM waterpump, backflushed the cooling system, double row radiator, all new cooling hoses, etc. Now why do you suppose it runs a little warmer than most...hmmm....I wonder why....now why do you think it runs too warm with the stock thermostat.....hmmm....thinking................thinking.......................... oh I got it...maybe because it has something called a TURBO!!!!!!!!!!! Turbos run hot by nature and will increase the heat of the oil and the engine. Most people on this board with a EA82T/EA81T run an Oil Cooler and a 180 degree thermostat to reduce the temperature. Do you call oil coolers a BANDAID? Then why did EA81T come stock with an oil cooler?

 

My car does pretty good with a 180 degree thermostat with no oil cooler and running stock everthing. Most people here try to push their EA82T to the limit and to do that, you have to do cooling system mods like double row radiators, oil coolers, and even lower temp thermostats. Otherwise, expect a cracked head.

 

Incorrect coolant mixture will reduce cooling ability (no - you should NOT run 50/50 in CA).
Now what is this about??? I run 50/50 in CA. Everybody here does. If not 50/50, then what? All shops and dealerships will tell you to run nothing less than 50/50 and nothing more than 30% water and 70% antifreeze no matter where you live. 50/50 sounds pretty good for 70 degree temperatures.
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The 50/50 mix is good for most driving environments. Extremely cold ones would go towards the 70/30 mix (antifreeze/water). In extremely hot environments, the opposite. Prestone markets a Tropical Blend premixed coolant for hot areas like the Carribean. It's 34% coolant to 66% water. Antifreeze/coolant does not transfer heat very well hence never use antifreeze/coolant by itself without mixing with water.

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You did not say you had a modified engine. If you are going to modify things, then a different thermostat *could* be a part of that modification. My personal take on these issues is that the engine was not properly designed, and thus is not a good candidate for "mods" anyway. But do as you like.

 

As for coolant mix - I sugest a good book on the subject, but suffice to say that more water will cool your engine better. Try it. It's a balancing act tho - as the "anti-freeze" is also technically an "anti-boil" too. Lowering the amount of anti-freeze will lower the boiling point, and raise the freezing point. But WATER tranfers heat more efficiently, so more water will make your cooling system more effiecient.... to a point. That point is where the boiling point is too low, and you get steam (which BTW - doesn't tranfer heat AT ALL for our purposes. NOT good).... which blows the radiator cap. I sugest a 25/75 mix. That's what I run in oregon. 50/50 is good to like -30 degrees or some silly thing. A temp that I have never seen here on the coldest winter day. I'm sure in CA you would probably be in a world of hurt if it ever got that cold....

 

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OK guys, we just covered this antifreeze mixture issue in class earlier in the semester. Ethylene glycol reacts with the minerals and deposits in the water to change the boiling point and freezing point of water. By itself, the freezing point is actually higher and boiling point lower than when mixed with water. keeping a mixture of 50/50 has the broadest temperature range without freezing or boiling the coolant. I believe you can go 10 or 20 percent either direction to obtain coolant better for higher or lower climates. 30W/70A for colder climates, and 70W/30A for warmer climates. BUT when you do this the range gets narrower. For that colder climate it might boil persay at 25 degrees cooler than 50/50 when you only gained 10 degrees lower on the freezing point.

 

What I am trying to say, is just go with 50/50 for MOSTLY EVERYWHERE. changing coolant mixtures might be for if you lived in alaska or something. And thats what I put my vote on.

-Mike

 

(btw, for those that dont know, dont use bottled or distilled water for your coolant. Use hose water, the antifreeze needs those impurities.)

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So what exactly is wrong with using distilled water? All the makers of pre-mixed coolant use demineralized (distilled) water in their production process, and all the car manuafacturers sugest distilled water.

 

"Premixed with demineralized water to provide freeze protection down to -34°F":

http://www.valvoline.com/pages/products/product_detail.asp?product=14

 

"Water quality is critical. Vehicle manufacturers recommend mixing distilled water with antifreeze. Don’t use tap water, which may contain minerals that will corrode your cooling system. Do not use water softened with salts.":

http://www.eetcorp.com/antifreeze/antifreeze-faq.htm

 

"Yes, tap water is commonly used for mixing with antifreeze, however, deionized water or distilled water is preferred. Do not use water softened with salts to mix with antifreeze."

http://www.peakantifreeze.com/faq.html

 

Antifreeze does not react with the minerals in the water to change the boiling point and freezing point - it reacts with the WATER to do this. I have no idea who told you that or why, but it's completely wrong. Actually - adding ANYTHING to pure water will raise the boiling point and lower the freezing point to a certain degree. That's why we use salt on roads. It disolves into the ice, and lowers it's freezing point. The outside temp is no longer enough to keep it solid, and it melts.

 

A 25/75 mixture will protect down to about 10 degrees, and boil at about 200 degrees. The system is designed to operate at a continual 195 degrees on an EA81, and with a 13 psi system pressure you raise the boiling point another 40 odd degrees or so. Now I have a range from 10 degrees to 240 degrees with a system operating temp of 195.

 

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I'm sorry, but all my teachers, one of which has 50+ years in the automotive industry and is retiring this year, say that it is better to use tap/hose water. Yes I am sorry I did not mean to type it as reacting with the antifreeze, I did mean to say reacting with the water as far as boiling point. What the impurities do with the antifreeze has to do with the lubrication of the water pump bearing and seal. I am not saying go down to your local city drainage creek and fill your radiator up with that... Heck no all that stuff will definetly build up deposits, but using distilled water doesnt gain a darn thing. Why its recommended is for most people out there that decide to flush their radiator every 15 years whether it needs it or not.

 

*Once the ethylene glycol starts breaking down and becoming alkali, then you get electrolysis action and corrosion from regular tap water yes. If you do it every 2-3 years like you're supposed to, this corrosion never happens.*

 

 

Normal operating temperature on a warm day is like 220 degrees for most modern engines. thats cutting it close for me... with 50/50 were talking a boiling point of 230 degrees plus the pressure bringing it up to around 270ish , and still having a freezing point of around 10-15 degrees.

 

So what exactly is wrong with using distilled water? All the makers of pre-mixed coolant use demineralized (distilled) water in their production process, and all the car manuafacturers sugest distilled water.

 

"Premixed with demineralized water to provide freeze protection down to -34°F":

http://www.valvoline.com/pages/products/product_detail.asp?product=14

 

"Water quality is critical. Vehicle manufacturers recommend mixing distilled water with antifreeze. Don’t use tap water, which may contain minerals that will corrode your cooling system. Do not use water softened with salts.":

http://www.eetcorp.com/antifreeze/antifreeze-faq.htm

 

"Yes, tap water is commonly used for mixing with antifreeze, however, deionized water or distilled water is preferred. Do not use water softened with salts to mix with antifreeze."

http://www.peakantifreeze.com/faq.html

 

Antifreeze does not react with the minerals in the water to change the boiling point and freezing point - it reacts with the WATER to do this. I have no idea who told you that or why, but it's completely wrong. Actually - adding ANYTHING to pure water will raise the boiling point and lower the freezing point to a certain degree. That's why we use salt on roads. It disolves into the ice, and lowers it's freezing point. The outside temp is no longer enough to keep it solid, and it melts.

 

A 25/75 mixture will protect down to about 10 degrees, and boil at about 200 degrees. The system is designed to operate at a continual 195 degrees on an EA81, and with a 13 psi system pressure you raise the boiling point another 40 odd degrees or so. Now I have a range from 10 degrees to 240 degrees with a system operating temp of 195.

 

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But any impurities that are "needed" by the system ought to have been put in the antifreeze by the manufacturer don't you think? I would conjecture that this is why they recommend distilled water. Everything else has already been added. I have never heard of the water pump bearing and seals needing anything of this sort. Which is quite odd considering the number of automotive classes I've taken over the years.

 

I cannot imagine this to be possible considering the different qualities of tap water all over the world. There would be almost no way for the manufacturer to know what mineral content you will be using unless they put it in themselves. Water here in the US is some of the softest in the world, and I would think that if mineral content were any sort of factor we would be blowing up water pumps on an unbelieveable scale compared to the rest of the world.

 

Freezing temp with 50/50 is more like -30 degrees.

 

I do agree tho that people do not change their coolant often enough. And you are correct that some of the additives (such as zinc) will deplete after a time, leaving the engine unprotected against electro-chemical corrosion.

 

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  • 1 month later...
I'm sorry, but all my teachers, one of which has 50+ years in the automotive industry and is retiring this year, say that it is better to use tap/hose water.

I do not mean to insult anyone with the following comment, but it is just something which occurred to me.

 

I have heard often times that the younger generations disagrees with the older generations when it comes to auto maintenance. Generally on things such as coolant to water ratios, oil weights to use, etc.

 

It is obvious to me that there are different schools of thought on this. One is maintained by the older generation, and one that is brought forth by the current one. It is the age old argument between the "tried and true" versus the "new and improved."

 

I am not taking sides here :P, just thought I'd make this point is all :D.

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