serious long term overheating problem

ok i'm getting aggrevated with it so i'm finally making a post..ok so about a year ago my car got in a mood where it wanted to overheat but i could rev it or drive it and it would almost drop from close to redline to operating temp in a split second,almost made me think the gauge was faulty..the car didn't do it for about a year until about a week ago my car starts doing the same exact thing so i decided to flush the system and put in a new thermostat while i was changing the oil and blah blah.. later on that night the car did something it never had before..it started getting hotter and the heater quit working and would not cool down until i pulled over and loosened the cap and let off the presure,so i sat and let the car cool and drove it about a half mile back home and re bled the system and the car ran great for a couple of days until today when it did the exact same thing again twice today..i found a broken sensor which was the fuel tank vent solenoid which i think has nothing to do with it but i am pretty much clueless..any help would be appreciated really wanting to get this fixed before i get my tune for my top mount and meth

 

Sounds like air in the system.. are you sure the coolant lines from the top swirl tank are connected right? Its common for someone to get those backwards... which will cause the car to loose coolant when it gets warm and suck in air. It repeats that until the car starts to overheat.

 

i'm pretty sure they're right..i dont know of me ever taking them off for any reason..any way to tell?

 

yeah the line from the top cap should t into the lower cap and overflow. Then the top of the swirl should goto the passanger top side of the radiator.

 

yea i'll try that doug thanx

 

and i've already changed the upper and lower radiator hoses,radiator,and thermostat btw

 

possibly a headgasket if not those other things??

 

What does the fuel tank vent solenoid look like? I think mine may be faulty as well.

Thanks!

 

i dont think its a head gasket because the car runs perfectly when its not doing this crap..and no water in oil or any other signs of a head gasket..beleive me i know,i have a 1g dsm project car i'm trying to build for drag racing and it likes head gaskets lol

 

fuel tank vent solenoid

 

ok the pic isnt working heres the page link- http://viewmorepics.myspace.com/ind...ndID=6954381&albumID=2571828&imageID=71263064

 

Better?

 

yes much better how do you post it like that?

 

You do this in front of the url

Or you just click the insert image button (button with the mountain in it) and paste the full url in that.

 

Thanks!

Okay, is that under the hood or near the tank?

I have the 2004 WRX/ STi service manual and can't find it

 

It's under the hood mounted to the intake manifold right behind the ps pump. I think in that manual it's called the Purge Control Solenoid Valve. I know this because I broke the nozzle on mine earlier this month putting in a new ps pump.

 

is this valve neccesary? i got a cel light for lean on bank 1 and i plugged it off and the car seems to be running and idling better now

 

I have mine wired up just so I don't get a cel but the lines are capped so I don't run lean.

With the fuel rail and intake I have two of the three lines to the valve didn't connect to anything.

 

i'm camping in stone mountain right now about 2 or 3 hours from my car but ill check what doug said as soon as i get home tommorow..how hard is it to change a water pump on an 05 sti if thats the problem?

 

car ran good for two days and as my turbo timer was counting down for about 2 minutes i came back to the car and it was running hotter than operating temp but not too hot..i dunno what the hell is wrong with it but i'm ready to find out

 

one thing i've noticed is that the car really only tries to overheat when i'm driving really slow or parked..i checked the fans and they both are working

 

I still think it's trapped air. I'd let the car cool all the way down, pop swirl cap off and let it run with the heat on full blast for 30 mins. That will allow any trapped air bleed out. That is how I bleed my car and never had issues.

 

ok i can try that..which cap should i pop off? the radiator or the upper one?

 

The upper one....that's the swirl pot.

 

and do you pop the cap completely off or just loosen it?

 

oh ok got ya i'll try it in the morning

 

I take mine off completely so I can watch and add if needed.

 

wouldnt it try to blow out the cap after running that long?

 

It will some but since the pressure can't build up it won't just blow out....it'll overflow. When you turn the car off you then fill up the rest and drive it. Really 10 mins should be ample time though.

 

ok cool i'll try that..i compared my coolant lines to my cousins 05 sti and they were the same..so i'll try bleeding it like that now

 

going to try coolrex's idea..maybe it'll work

 

Maybe it'll work....who knows.

 

just got finished i done it for at least thirty minutes..got a lot of air out..guess i'll find out when i drive it soon..when i was almost finished i revved it with the cap off a little and it blew a hell of a lot of bubbles out along with a little antifreeze..it blew at least 2 to 3 inches high of bubbles out every few times i revved it

 

Did you turn off the car and top it off?

 

Also is it tiny bubbles or is it like burbling bubbles? Lots of tiny bubbles is an indicator of blown head gasket (at least on a DSM it is and I don't see why the same won't apply to Subarus).

 

Just double checking...when you bleed your coolant system, are you running it with the heater running wide open? If not, you should... no amount of burping will compensate for the air trapped in the heater core.

If so, nevermind.

 

I told him to. Lets hope he did.

 

yes i ran the heater wide open..and the car did perfect for about an hour but then i parked and let it run and it started heating back up again..it heated up really quick but once i started driving it dropped back down to operating temp in a matter of seconds..and the bubbles were pretty big

 

I dunno man. If the bubbles only happened when you revved it that normal....you are suddenly making the water pump spin faster.

Sounds like air still or a faulty thermostat even though you just replaced it.

 

i may try another one..its not too expensive..and the bubbles were only when i revved the car hard

 

i'm gonna let the car cool and check my coolant levels and bleed it some more i guess

 

doesn't it mean air in the system if when i turn the car off i hear water gurgling around? i just noticed it but it does it everytime i shut the car off even if its not trying to run hot

 

doesnt make any sense..i've driven the car the past few days a lot and it doesnt even try to run hotter anymore..i guess i wont complain lol