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2003 Forester A/T
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Discussion Starter · #1 ·
Hey there guys, I hope I'm posting in the correct place.
Im having a small issue with the temperature gauge rising when I'm driving on the highways. In particular when I reach 100-120 KM/H. Now it doesn't rise into a zone to be worried about but still rises all the same. When I turn on the heat it brings the gauge right back to where it should be. So if your looking at the temp gauge, 4 notches, normal operating temp is just sitting above the second marking. When im on the highway, it rises to the third marking, I then ease off to about 80KM/H and with turning the heat on it returns to where it should be.

I did replace, timing belt, water pump, thermostat some weeks ago. I figured I did get all air out of the system, spent a long time at it doing it the conventional way.

So this leads me to two things, theres still air trapped in there or its down to the gates thermostat which I used.

Should I try bleed some more before I pop out the gates thermostat and replace it with a Subaru one?

I should also mention, I'm not particularly worried right now about the head gasket, appears to be holding coolant and theres no evidence of oil & water mixing.

If anyone has experienced similar, your help would be appreciated!
Thanks
PJ
 

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2007 Forester Sports XT 4EAT
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Assuming your head gaskets are not failing. I have read where members have had issues with aftermarket thermostats. They installed a factory/OEM thermostat & the problem was resolved.

Bobby...

['07 FSXT MODding Journal] ['03 X MODding Journal]
 

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Can I assume you bled from the heater hose valve?

There have also been instances where a thermostat was installed backwards?
 

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Discussion Starter · #4 ·
Hey Kevin, sorry for my late reply. I bled it from the top of the rad, is there a more efficient way to get it done?
Cheers
Pj
 

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@retrokipper My MY'03 has a bleeder valve on the heater hose (I'd take a pic but it's 4am!) this is the process:

For Non-turbo model , remove the air bleeding valve cap of heater hose.
2) Fill engine coolant.
3) When engine coolant is filled up to the air bleeding pipe (valve), install the cap.
4) Fill engine coolant into the radiator up to filler neck position.
5) Fill engine coolant into the reservoir tank up to Full level.
6) Warm-up the engine completely for more than 5 minutes at 2,000 to 3,000 rpm.
7) If the engine coolant level drops in radiator, add engine coolant to filler neck position.
8) If the engine coolant level drops from Full level of reservoir tank, add engine coolant to Full level.
9) Attach the radiator cap and reservoir tank cap
 

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2019 Crosstrek 2018 Forester XT
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The proper way to fill is remove the top rad hose connection to the radiator. Fill the radiator full. Fill engine thru the top hose connected to engine. Done and done.

You might have to remove the radiator once when cold and just fill the radiator to the top. Thats unlikely. I doubt your problem is the radiator.

To check remove the cap when cold and verify the coolant is to the top. If not fill it.
 

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Has this "rising temp at high speeds, which then goes down with turning the heater on" happened several times? If so, I think your heater core is adequately bled. Had you needed to add much fluid to the overflow bottle (once cooled down)?

If your fluid in the overflow bottle is at the same level day to day, when cold, then there's not much air left in the system. That leaves the thermostat, water pump, or possibly a gunked up radiator as the culprits. What water pump did you use? Don't assume any old aftermarket will be fine. Just saying.....

Unfortunately, as you probably know, to replace the water pump is a chore. I think i'd start with the thermostat.

If you are still needing to add coolant to the bottle or radiator, then you either had not gotten it completely bled (we shall hope for your sake this it the problem) or you have a leak that you are missing -- slow ones can be missed, but should not cause overheating. Or finally, the dreaded coolant to cylinder HG failure that leaks coolant into the combustion chamber.
 

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Discussion Starter · #9 ·
Hey everyone, thanks for all of your input! Im not too sure how to tag people in the post so ill start with @Kevin and work my way down. I wasn't aware of the bleeder valve on my model, I figure it was dohc/turbo models. Ill check it out however. If you could shoot me a pic that would be awesome. @adc I will try your method in the coming weeks, when I replace the stat for a Subaru one. @cdherman, I too believe the system is now fully flushed of air. Its not loosing coolant, theres no leaks & no signs of head gasket failure. I used a Gates Belt and WP kit & a gates stat. I will be replacing it with a Subaru one in the coming weeks and report back. Had some problems today on the highway, went to overtake a truck (wasn't gunning it) and all of a sudden lost power. Had the check engine light flash. Felt like a strong misfire, so when I got off the highway she was undriveable. Just wanted to conk out. I scanned it with my cheap scan tool and it gave me misfire on cyl no.2. So I walked to the nearest Napa and picked up, plugs, wires & ignition coil. Put it all in, it did help but didn't fix the issue. It was then giving all sorts of codes, P0301, P0302, P1700, P0108. Its jerking quite hard and giving an intermittent check engine light. I managed to get it home. Its driveable now, but very though to drive.
 

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just experienced a very similar issue in my 04 XS auto. turned out that the OEM radiator cap could no longer hold the required pressure. under stress, coolant would spill up and out of the cap causing the engine temp to rise. simply replaced the radiator cap... problem solved.
 

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Im not too sure how to tag people in the post
Fixed ;-)

I wasn't aware of the bleeder valve on my model, I figure it was dohc/turbo models. Ill check it out however. If you could shoot me a pic that would be awesome.
Here it is; right next to the air filter housing and just in front of the fire wall. It can be opened with a phillips head screwdriver.

 

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The way I described above is from the workshop manual for the MY'03 so I consider it the "proper way" for that vehicle and I've never had any issues after refilling the radiator by following it.
Thats fine. Folks can choose. My subaru specialist fills it this way. No burping..ever.
 

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Discussion Starter · #14 ·
Thanks Kevin, I will have a look for it now that I know what it looks like. Poor little guy is very sick atm!!!
 

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@2.5x_sleeper indeed it is Bobby - also as per the copied bleed instructions I gave earlier in this thread. SG turbos do not have this valve but rather says "1) For Turbo model, remove the rubber cap of air bleeding pipe at compressor left side in front of engine, and then install the vinyl hose."

Publication G8070GE1 cooling systems SOHC page "CO(SOHC)-18".

"These manuals are used when performing maintenance, repair, or diagnosis of the Subaru FORESTER.
Applied model: SG***** from 2003MY"
 

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@Kevin it appears there are differences... perhaps country differences? :confused:

My Subaru technical service document doesn't have a "CO(SOHC)-18" page? There is a page "CO(H4SO)-17" & "CO(H4SO)-18", but there is no mention of that air bleeding pipe?

Take a look at the picture below. It's my son's '03 X engine as it was being prepped for the AVO turbo kit installation. Note that there's no air bleeding pipe!

Bobby...


['07 FSXT MODding Journal] ['03 X MODding Journal]
 

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@Kevin, this is what's in my FSM, for the '03-'04 H4SO - NA, nonturbo engine. :wink:

The next page, CO(H4SO)-18, is just a discussion on antifreeze concentration & safe operating temperatures. The recommended concentration is a 50% concentration... distilled water to antifreeze.

Bobby...


['07 FSXT MODding Journal] ['03 X MODding Journal]
 

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