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1995 2.2 Auto Legacy Sedan
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142 Posts
Discussion Starter #1
Over the last three weeks the temp gauge will go all the way to the white line just under the red and stay before it drops and other times it will stay there. You can tell it is hot because the AC struggles to cool. I can tell when the tstat opens as it will cool down. It has been sporadic with no warning lights on the dash. The fans are working and the lower hose is new. It is hard to duplicate and sometimes it will cool right down when you drive and other times it will not. Seems like a sticking tstat. Wouldn't there be a dash warning light if it was getting that hot?
ps, I did search the forum and did not find an answer to my question.

Thank you,
 

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03 H6 OBW & 06 WRX Sportwagon
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17,545 Posts
If the car has a decent history otherwise, it may just be time for a rad cap, t'stat and maybe a flush and new fluid. (how old are they?)

I suppose there could be hoses collapsing or something more of a 'repair' needed.
 

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1995 2.2 Auto Legacy Sedan
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142 Posts
Discussion Starter #3
Flush n fill is good. I do not know about the radiator cap or t-stat.
 

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2001 VDC/SC One of a Kind
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14,289 Posts
Getting hot then cooling down is generally a sign of low coolant. Look for a leak and you should go ahead and replace the thermostat. When the thermostats reach high temperatures several times, the performance suffers.

For future reference, the ECM will shut the AC off when engine temperature reaches 220 or higher. This serves two purposes, one to reduce engine load and two to help cool the radiator by stopping the flow of hot freon through the condenser which increases the cooling on the radiator.
 

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1995 2.2 Auto Legacy Sedan
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142 Posts
Discussion Starter #6
I will go ahead and get a oe tstat; I think that will probably do it as that is what my original thought was too.

Thanks for your help and knowledge,
 

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1995 2.2 Auto Legacy Sedan
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142 Posts
Discussion Starter #8
Well...darn the oe tstat change out did not due the trick and it is leaking around the housing now. Is their a certain position the tstat is supposed to be in? Seamed pretty straight forward and I was suprised to find it leaking. I did burp the system and noticed the bottom hose I replaced in June feels a little too soft. Wonder if the hose could be collapsing? but does not seem to be when I am inspecting it. I know the coolant is new. Fans are working. Any suggestions?
 

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2005 Legacy 2.5i Wagon 4EAT; 2005 Forester XS 4EAT
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672 Posts
The guy I bought mine from told me about a Forester he sold that had trouble with overheating.

After replacing everything possible, including head gaskets, it turned out to be the hose going into the top of the overflow bottle. The bottom of the bottle was full of sludge, and the bottom of the hose was going right into it. He took the bottle out, scrubbed it out, snipped about an inch off the hose, and that solved the problem.
 

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'14 3.6R Outback
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2,345 Posts
Well...darn the oe tstat change out did not due the trick and it is leaking around the housing now. Is their a certain position the tstat is supposed to be in? Seamed pretty straight forward and I was suprised to find it leaking. I did burp the system and noticed the bottom hose I replaced in June feels a little too soft. Wonder if the hose could be collapsing? but does not seem to be when I am inspecting it. I know the coolant is new. Fans are working. Any suggestions?
On every car I have ever worked on there is a gasket in that housing you need to replace when you change the thermostat.

There is a wrong way to install a tstat. There should be a flow arrow --->
 

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1995 2.2 Auto Legacy Sedan
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142 Posts
Discussion Starter #11
Well after stepping away and posting my thoughts I went back to it and snugged up the bolts on the housing a touch more and the leak stopped. Hooray...There was a new gasket on the new tstat. I then washed through the radiator with a high pressure spray. I noticed that I now have two speed fans. I am positive they only ran at low speed when I checked it before. When the com[pressor for AC kicks on it brings both fans on high speed. When the compressor shuts off they go back to low speed. I am sure it must be a fan speed problem. They were not hitting high speed and now they are. It is also running fine and not over heating again.
 

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2001 VDC/SC One of a Kind
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14,289 Posts
I hope you installed the wobbler on the up side when you put he thermostat in.

Sounds like you may have been low in coolant prior effecting the function of the ECT. The fans won't come on for high speed for cooling only until around 220. The ECT signal to the ECM controls when the fans change speed when the AC is off. The fans are high volume to start with, even on the low speed which should start up at 203.

If you have a scan tool you could watch the fan operation and speed in relation to what the ECT is sending. Of course, forcing it up past 210 will be a chore with a new Tstat and coolant.
 

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1995 2.2 Auto Legacy Sedan
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142 Posts
Discussion Starter #13
I hope you installed the wobbler on the up side when you put he thermostat in.

Sounds like you may have been low in coolant prior effecting the function of the ECT. The fans won't come on for high speed for cooling only until around 220. The ECT signal to the ECM controls when the fans change speed when the AC is off. The fans are high volume to start with, even on the low speed which should start up at 203.

If you have a scan tool you could watch the fan operation and speed in relation to what the ECT is sending. Of course, forcing it up past 210 will be a chore with a new Tstat and coolant.
I put the wobbler (never heard that one before) on the low side. What effect will it have? I would have thought the fans were temp controlled but they did come on high speed exactly when the compressor came on and went back to low speed exactly when the compressor shut off every time. I know the condensor for the compressor will cause the coolant temp to rise when the compressor is running but it is an immediate response. I will see how it goes. My wife is real good about letting me know when something is wrong with her car; She really pays attention.
Thank you all for the knowledge and advice:29:
 

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2001 VDC/SC One of a Kind
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It wasn't the fans. That's how they are supposed to operate.

I try to use simple terms where I think it will help describe what I am talking about. Sometimes I forget and tend to confuse people. I'll see the look on their face and think to myself, "too technical".

The "wobbler" needs to be on the top to assist in bleeding air from the block side of the thermostat.
 

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1995 2.2 Auto Legacy Sedan
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142 Posts
Discussion Starter #15
Back at it again. I am starting to think it is a temp sensor problem with the needle going in and out of the red so often. Tonight when I got home I let it idle even though it showed to be hot. Checked out the temps with a cheap harbour freight laser thermometer and found the hottest spot was 200. Top of the radiator was 160. I would say the average temp was 150-160. In no way did it seem Hot or make me have an Oh Chit moment. I believe the sensor is also shutting down the compressor when it is telling the computer it is hot. I did notice the driver side (oil leak on this side) ran 10 hotter than the non leaking passenger side. Where is the temp sensor located? I still have not flipped the wobler around. Also do the cooling fans shut down when it is in gear and you accelerate from a stop light? Also what is the best kit to use to check for exhaust gas in the anti freeze. I am not losing fluid at all but it was overheated at one time and the oil leak may be a warped head and that could be my problem. Sorry for the long read, I am getting frustrated.
 

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2001 VDC/SC One of a Kind
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The sensor is in the head behind he dipstick.

The fans will remain on if the temperature of the engine dictates a need regardless of the pedal position.

The AC shuts off with WOT which also shuts off the fans if the fans are only on for the AC operation.
 

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2017 3.6R Limited (Wifes), 2009 3.0R Limited 125k (Mine)
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241 Posts
When the temp is approaching the red is the overflow taking on coolant? After the car sits overnight is the coolant full and up to the neck/cap of the radiator. When starting the car after sitting overnight do you hear a swoosh coming from the heater core or dash area? If so, there is air in the system. Burp the system again. This could also indicate HG failure. Someone mentioned cutting the over flow tube which is also a good idea. You want to make sure that is not making contact to the bottom of the reservoir. Make sure there is at least ½ inch between the angle cut of the hose and the bottom. Also make sure the reservoir is clean.
 

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01 Outback LL Bean
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2,414 Posts
Not sure what all this talk of a wobbler is about, but the bottom of the thermostat, the side with the spring in it, needs to be in the block. Which basically means the thermostat goes in upside down. It is not clear what your orientation is but if the spring side is in the hose that will cause all sorts of issues.

The temp sensor is located at the front of the drivers side head.
 

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Probably nothing, but I noticed that there's no mention of the fans ever being off when the engine is running.

With the AC and the heater fan turned Off, do the fans start up (slow or fast, doesn't matter) as soon as the engine is running? Even with a "cold start"?
 

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1995 2.2 Auto Legacy Sedan
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142 Posts
Discussion Starter #20
When the temp is approaching the red is the overflow taking on coolant? After the car sits overnight is the coolant full and up to the neck/cap of the radiator. When starting the car after sitting overnight do you hear a swoosh coming from the heater core or dash area? If so, there is air in the system. Burp the system again. This could also indicate HG failure. Someone mentioned cutting the over flow tube which is also a good idea. You want to make sure that is not making contact to the bottom of the reservoir. Make sure there is at least ½ inch between the angle cut of the hose and the bottom. Also make sure the reservoir is clean.
Yes the overflow does take water and the reservoir level rises and is clean. No swoosh. Spring also is facing correctly on tstat and the car is acting just like it was before.
The fan is off on cold starts.
I am leaning toward the sensor located on the leaking oil side of the head being messed up from being saturated in oil. I will try and get that valve cover replaced and do the plugs while I am in their.
How would I test the temp sensor/sender on this vehicle?
 
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