'91 Legacy Wagon Destroying thermostats?

[MizzJesi]

Hi Everyone!   

     I am new to the forums and so glad to have found it! LOL I recently perchased a 91 legacy wagon that I love   , but since buying it, 4 months ago, it has destroyed 2 thermostats.    Has anyone heard of this before? Is there a specialised thermostat that could help? I realize that I dont HAVE to have a thermostat, but would like to have one. I was told about the "failsafe" thermostats, anyone recommend or not recommend those? thank you to anyone who can help me!! Im at my wits end here. Lol 

[Prwa101]

Haha where are you buys these thrumastats? I'm guess cheap ones from napa or car quest. You want the ones that is closest to the oem as possible, any difference and it won't work well. Can't remember what brand we use at the shop. Try getting and oem from Subaru can't be more than 20$

 

-Prwa

[Fairtax4me]

Subaru OEM or Stant Exact-stat are the only two that will work in these cars.

Both are costly, but you'll never have to replace them again.

 

What symptoms do you have that lead you to replace the thermostat to begin with?

[MizzJesi]

Thank you guys! Thats kind of what I figured but in calling around the stores here all they would say is "A thermostat is a thermostat". I figured it had to be that they just were not the right ones for my car. 

 

 

Fairtax,

    I replaced the thermostat the first time because the car over heated when it was full of water, so safe to assume that the water is not getting to the engine, only 2 resons for that, 1 a blocked radiator, or 2 a thermostat, since the thermostat was cheaper I started there. After removing the thermostat I then tested it ( In a pan of boiling water) and it of course did not open, which (along with the over heating being sloved) told me that I had been correct in starting with the thermostat. Of course at the time I thought it odd that what looked like a new thermostat had gone out. But chalked it up to bad parts, so called parts store, got a new thermostat, installed it and it worked great for another couple of months. Untill today that is, when I fould myself stranded on the side of the road with an over heated car again. So I decided that before I went through the trouble of replacing the thermostat again, I would find out from people who know a bit more then I do about it, what I SHOULD be putting in there. I dont mind paying the extra to get the correct one, and will call tomorrow to the dealers and see if I cant get an OEM thermostat for it

    The reason why I dismiss the blocked radiator also is that my fluids are clear. There is no sign of deteriation or durt that could build up in the radiator. If getting the correct thermostat does not solve the problem, *sigh* I will have to turn to the radiator. 

 

            Thank you again!!! 

               MizzJesi

[Fairtax4me]

My biggest concern wih overheating an engine is possible damage to the head gaskets. The EJ22 is robust and head gasket failure is not common but still possible, and usually only due to overheating or poor coolant maintenance causing corrosion of the heads.

 

Very doubtful that your issues with overheating are due to a bad head gasket. It certainly sounds like the workings of a bad thermostat. Just hoping that this problem hasn't caused a larger one.

To avoid issues with air in the system, fill the engine block through the upper radiator hose before filling the radiator.

Also just want to be sure, you're not filling with straight water are you? Antifreeze does play a part in slightly raising the boiling point of coolant to prevent boiling in the block at normal running temperature.

[MizzJesi]

I have also been concernd with the over heating causing damage to the heads, so far I have found no oil/water mix. And yes I do normally have coolent/antifreeze in, a 50/50 mix of water. 

and thank you for letting me know about filling the engine first, That I had not heard but will surely do as soon as I get the thermostat replaced (for the last time I hope) lol 

[heartless]

also a good idea to keep a close eye on the coolant level for a week or so after doing the t-stat change.

 

Filling the block first is always a good idea to reduce the amount of air in the system.  Filling with the front end slightly raised will also help minimize air pockets, but there will always be small pockets that will eventually work thier way out, leaving you with a slightly lower coolant level - keep tabs on it and add a little as needed (I add in the overflow bottle to the "full cold" mark when engine is cold, they system will draw in what it needs) until it remains steady for several days to a week. at that point it should be good.

[ivans imports]

Subaru factory thermo only no others will do I a'm constantly having to fix cheesey aftermarket ones changing the thermostat will not fix headgaskets but people keep trying

[MizzJesi]

LOL @ Will not fix head gaskets!! really? are people that brainless? 

[johnceggleston]

there are several possible causes of the overheating.

 

1/ bad t-stat

2/ air trapped in the cooling system

3/ a coolant leak or leaking rad cap

4/ bad head gaskets.

 

given the time frame of the repeat over heat, i suspect 3, or 4.

hopefully not 4.

probably not 2, if it were air trapped in the system i think it would have shown up sooner than a couple of months.

 

before i bought any more parts, i would fill and burp the system so you know it is ok.

then i would drive it until it over heats, IF it over heats.

(if it does not overheat, you are done.)

if it does overheat, look for bubbles in the over flow reservoir, this is a head gasket indicator.

 

if there are no bubbles, i would replace the cap, refill the system and look for a leak.

(my 97 outback leaked at a lower hose clamp, but only after the system reached full temp. not when cold or first started.

i found it by letting it sit idling in my drive way after coming home after work.

i saw the drip on the concrete.)

 

info and a 'how to' below i posted on another forum.

 

good luck.

 

 

 

 

how to fill and burp your cooling system.

taglines: burpcoolingsystem; suphonfill; burpcoolantsiphon.
 

compiled from previous posts.

 

PART 1>

1/ remove vent plug on radiator at top hose.

 

2/ fill radiator at fill neck / cap SLOWLY. (slowly is key.)
(i have written this a couple of times and it works great, for me. but
it is so odd and extreme i really don't expect any one to follow it. sit
the jug of coolant on the passenger strut tower and use a long tube,
about 1/4 inch diameter, to siphon the coolant in the rad. the process
is so slow you will get bored, but slow works in this situation. )

3/ when full install the vent plug and rad cap.

4/ start the engine and run it up to full operating temp. then shut it down and wait for it to cool down.

5/ open the rad and top it off. mine usually only takes a couple 3-4 oz.
(most folks run the engine with the rad cap off to burp it. but i have
found that when it burps it looses more coolant than it really needs to
so i just heat it up and then let it cool before i open it. all you
really want to do is circulate the coolant and eliminate any air
bubbles. the siphon is so slow it really does not need much burping or
topping off. this is different than most other fill and burp process. )

good luck.


PART 2>

the last 2 times i have filled an empty cooling system on an ej25
engine, i have used a very unusual method and have had NO problems and
have not had to burp.

i put the gallon of coolant on top of the engine, either the passenger
strut tower or the air box near the firewall. i then use a small
diameter tube (~5/16 inch, inside diameter) to siphon the coolant out of
the jug and into the rad. (it helps if the tube is clear so you can
see the coolant as it gets close to your mouth.) after the jug is
empty, i then start over with a half jug (2 qts.).

this is a very slow process because of the size of the hose, but more so
due to the very small difference in height. the system fills very
slowly and has time to back fill the engine thru the top rad hose. i
make sure the rad cap is at least level with or usually higher than the
rest of the rad. having the vent cap open helps too.

the first time i did it i tried to burp it but i ended up wit h less
coolant in the system than when the siphon had finished. so this last
time i just let the siphon do its thing and then put the cap on. no
problems.

it works great, but it is really, really, slow. so i do it while i'm
finishing up the last little bits of whatever i'm working on.

this is so slow that if you did it and then watched it you would give up
and start pouring long before it got done. but it is a great time to
open a beer and admire your work.

i doubt this is a good technique for a car that needs to be burped, but it works great for filling empty systems.

HTH.


PART 3>

for 90s legacys, the small vent cap is the trick to filling correctly.
coolant WILL NOT flow into the upper rad hose / engine block unless you
have the vent plug removed. and even then you have to fill it SLOWLY.

once you have slowly added as much as it will take with the vent plug
open, close that, fill to the top of the rad and start the engine. when
the t-stat opens the coolant will burp out of the rad and the level
will drop. (in most cases it will drop, but if you filled it slow
enough the system MAY be full.) top it off and put on the cap.

(my solution to filling slowly is to siphon the coolant out of the jug
and into the rad. i use a 1/4''- 3/8'' clear tube about 10 feet long
that i bought years ago and i use it for all of my siphoning needs. it
fills the rad so slowly you get bored. but you can rotate tires or
change the oil while you wait. once it is full, mine will not burp. it
is full.)

on a side note:

if you used a non-subaru t-stat you are going to have trouble.
they do not work and it will over heat. i know some of you do not want
to believe this but it is true. i was one of them for a long time.

there are several parts on these engines that MUST be subaru. and hopefully you do not damage anything learning that.

SOMETIMES, not very often, a ''high quality'' replacement part will
work, but ''cheap'' aftermarket parts are never a good solution for
these ''subaru only'' parts. they end up not working correctly and you
not only have to redo the work (twice the labor) you have to buy
another, usually more expensive, part. buying parts twice is never cost
effective, even if your labor is free.

Edited June 14, 2013 by johnceggleston

[MizzJesi]

Thank you John, I am quite sure that my problem is cheap parts and that replacing the thermostat with OEM will fix the problem. I appriciate the how to burp! Refilling cooling systems is not something I do well ( bad experiance with an old honda accord that had a closed system) lmao. So seems I just need to get my parts and do it to it. Thank you so much for your help 

[twister5voy]

Sorry to bump a month old thread but....

Seems the only way to go is OEM on the thermostat. Tacoma Subaru is showing $43 for it, does this seem right? 

subarugenuineparts has it for $22. Are they actually OEM?

[MizzJesi]

that is a good question! hopefully someone can tell us cause now I wanna know! LOL 

[heartless]

either OEm or Stant Exac-stat - part number 48457 - this can be had for around $20

[Fairtax4me]

Sorry to bump a month old thread but....

Seems the only way to go is OEM on the thermostat. Tacoma Subaru is showing $43 for it, does this seem right?

subarugenuineparts has it for $22. Are they actually OEM?

Yes, parts ordered from SubaruGenuineParts.com are OEM Subaru parts. SGP is the online parts division of Chaplin Subaru in Bellvue WA.