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Quick question about thermostat


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Hello all. I just join in and i want to say greeting mates.

 

I have 2000 legacy wagon. The 76k original miles. 4 days ago, my radiator leak from the tank. I didnt use stop leak because i heard bad stuff about it. I replace my new radiator and idle air control valve. I reset the ecu today. It runs okay.

 

I have a bit of overheating problem. I thought it was the radiator cap, but i just replace it today. The water temp gauge is a bit slow to get to normal temperature. Once it reach normal temperature, the car not overheats. Maybe, 4-5min after the normal temps, the temps start to rising close to 3/4 (both fans turns on non-stop. When i turn the car off, both fans stop working and temps go down).

 

Radiator hose is just a bit warm. Like i can just hold it no problem. And the radiator tank seems cold. Now, I wait couple hours later for car to cool. I open the radiator cap and start the car. I let it go to normal temps. The black hole that you put radiator cap, the coolant dont seems to move at all... And yes its a bit smoking which is normal.

 

 

Questions:

 

1. Is this the thermostat?

2. Everytime replace the old clog..eventually leaky radiator, do you replace thermostat?

3. I dont think its the headgasket. Before the old very dirty radiator that causes clog and eventually leaks inside the tank..no bubble and all

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the t'stat MUST be an OEM-style (many people use a Stant Xacstat) but, it should look like this;

 

Thermostats%204%20sm.jpg

 

And it would be a good idea to replace it - typical HG failure would show bubbles in the radiator and often push fluid into the overflow tank.

 

thermostats can be tested in a pot of water on the stove top. They should open just before the water boils. I always test a new one. You could also test your old one.

 

DO NOT let pets or kids have access to radiator coolant (antifreeze) VERY toxic. clean-up any spills and don't leave any open containers/pans unattended. It tastes sweet and critters/kids will drink it and get sick or die. Kills about a dozen people every year i think.

 

A new radiator cap could be a good idea too.

 

No one reports problems using Subaru Coolant Conditioner (one bottle only - follow directions) and some have reported it slowed or stopped drips and leaks. It will do NOTHING for internal HG failure.

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Burp the coolant - it gets air pockets in it and you need to get them all out.

 

Some Subaru radiators have a plastic screw in the top passengers side you can bleed with.  Otherwise get nose high and fill through radiator cap inlet. Run car, cool down, repeat refill.  Do that a couple times. 

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Thanks for telling me. I was about to buy thermostat, but i didnt. I dont know if i did this right? Maybe too fast?

 

Before burping the radiator (yes this is a brand new radiator:

-heater blows cold air

-upperhose was cold

-radiator tank was cold too.

-engine overheats. I even bought a new radiator cap

 

During burping:

-I open the radiator cap and let it warm up while filling the coolant into the radiator.

 

-radiator turns on for a very long time because radiator and hoses is cold, but the temp gauge needle at half. Eventually, stops

 

-once the radiator and hose starts to warm, the fan stops.

 

-i keep filling the radiator whenever the coolant rush in(thermostat opens).

 

-during this, there was bubbles, but not that crazy like in youtube videos.

 

-after that, i kinda rev the car up and coolant spilled everywhere (should of NOT done that). I panick and turn the car off. Wait 10 seconds and start the car. Everything is okay (whew). There was smoke at the engine bay where the coolant spilled. My mom thought i blow the engine. It stop smoking though.

 

- I did this process for a long time.

 

-now the radiator hose is hot and the radiator is hot.

 

-yes the cooling fan turns on and the coolant rush in to cool the engine.

 

Done:

 

-now, the heater blows hot air.

-Radiator hoses and radiator is now hot.

-radiator fluid is hot.

 

Also, I did this process only ONCE and for ONE HOUR.

 

Did i do this right..?

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Is there a bleed valve on the engine?  If there is, it should be near the thermostat or the upper hose gooseneck.  It does sound like you have air in the block somewhere.

 

It's not a big thing that you did not replace the thermostat, but they don't last forever so I for one always replace them when ever I open the system up like that.  I never reuse coolant and with it going on $15/gal, I don't like buying it twice.  In your case, I would have also replaced the hoses, all of them.  Once and done is my motto for the cooling system.

Edited by keith3267
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Thanks for telling me. I was about to buy thermostat, but i didnt. I dont know if i did this right? Maybe too fast?

 

Before burping the radiator (yes this is a brand new radiator:

-heater blows cold air

-upperhose was cold

-radiator tank was cold too.

-engine overheats. I even bought a new radiator cap

 

During burping:

-I open the radiator cap and let it warm up while filling the coolant into the radiator.

 

-radiator turns on for a very long time because radiator and hoses is cold, but the temp gauge needle at half. Eventually, stops

 

-once the radiator and hose starts to warm, the fan stops.

 

-i keep filling the radiator whenever the coolant rush in(thermostat opens).

 

-during this, there was bubbles, but not that crazy like in youtube videos.

 

-after that, i kinda rev the car up and coolant spilled everywhere (should of NOT done that). I panick and turn the car off. Wait 10 seconds and start the car. Everything is okay (whew). There was smoke at the engine bay where the coolant spilled. My mom thought i blow the engine. It stop smoking though.

 

- I did this process for a long time.

 

-now the radiator hose is hot and the radiator is hot.

 

-yes the cooling fan turns on and the coolant rush in to cool the engine.

 

Done:

 

-now, the heater blows hot air.

-Radiator hoses and radiator is now hot.

-radiator fluid is hot.

 

Also, I did this process only ONCE and for ONE HOUR.

 

Did i do this right..?

Yes, burping the system takes time and pationce, where you will have to hold the idle up and force the thermostat to open, perhaps drive the car under load to heat it up. It is possible to overheat during the burp procedure if you are not familiar with how particular a subaru is. 

 

Here is a tip: fill the block by the upper radiator hose first, as much as she will take, before filling the radiator.

'

I have resorted to adding coolant to the heater hosed on tricky to burp engines.

 

IT almost makes more sense to run the engine to temp before opening the cooling system and filling before it has cooled down too much (as like a coolant flush would be performed in a professional procedure)

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You will get a check engine light (96 and newer) if your thermostat does not open in a prescribed time determined by your computer.  The time is based on outdoor temperature and conditions of warmup.  I had one set one time when the freeze data showed the coolant at 179 instead of 180 when the time was up.

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if you suspect it, you haven't lost much 'utility' from it if it is 60K miles old and you decide to swap it. I'm sure folks could report examples of thermostats lasting a very longtime. Some people swap them whenever they drain/refill their coolant.

 

also, they can be tested on in a pot of water on the stove, I test new ones before they go in too.

Edited by 1 Lucky Texan
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To the OP, if you've got the heater blowing hot now, you probably have it burped pretty well.  Is the problem still there?  If not, I'd say your good.

 

As for the T-stat, unless you're having problems wait and do it with the timing belt and water pump @ 105k.  You will drain pretty much all of the coolant out when you change it, and it's at the bottom of the water pump anyway.  I would HIGHLY recommend draining the radiator first when you do it, that way you only have the block pouring out all over you.  Also, when getting a t-stat, make sure it has the little bleeder port on it.  Here is a pic of one (not a subi stat, just the bleeder part).

 

bleeder.jpg

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-heater blows cold air

 

-upperhose was cold

this indicates that the coolant is not circulating.

burping and/or filling is needed.

when fill the cooling system,

slow is critical, in my opinion.

filling too fast can trap an air bubble,

and these sometimes will not burp.

 

 

 

if you've got the heater blowing hot now, you probably have it burped pretty well.

this is also correct.

 

my experience is some what limited,

but i have never seen a bad suabru t-stat.

all the talk of replacing ''bad t-stats'' falls into 2 categories,

either it is NOT a subaru t-stat,

or it was not the cause of the overheat.

 

obviously if suabrus go 350k miles some of the t-stat are going to go bad, maybe,

and lots are going to be replaced, just in case,

but i have never had, and i don't remember reading about,

a suabru factory t-stat being the cause of an over heating problem.

 

i have seen housings cracked and gaskets damaged during timing belt jobs.

and i have seen lots of off brand t-stats cause overheating.

and lots of overheating due to improper filling / burping, and bad head gaskets,

and one time i even found what look like a huge ''dust bunny'' on the engine side of the t-stat (stop leak?)

but never a suabru t-stat causing a problem by itself.

 

so if the engine i'm working has a subaru t-stat, i leave it alone.

 

just my experience and my opinion.

Edited by johnceggleston
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Thermostats are designed in 1 of 2 ways. Factory versions when they fail, they typically remain shut, which won't allow coolant to flow, or they stick (like from putting tap water in your system and mineral deposits mess it up). Some aftermarket units will fail in the open position. Those are complete garbage though and I've personally had 2 of them fail in my other car, with neither one seeing more than 2k miles in a year before failing.

 

 

I hope you've been using distilled water. If the issue doesn't straighten out with bleeding air (assuming that's the issue, I know VW has the issue as well with the 1.8L turbos) spending $7 for a new thermostat isn't going to hurt anything and will give piece of mind.

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