cooling issues..., fine when driving, spikes when stopped. Options

[malaga_red75]

subaru JDM EJ25 DOHC

So, got my conversion finally road worthy and have noticed that while I am driving around, the car stays at around 200 F. when i stop, or let it idle in my garage... the temp slowly climbs and doesnt stop (i shut it off around 230 F). I am assuming this is an issue with my fans.

I am running a front mounted radiator, using 2 push-style fans. A few things that i think may be wrong...

-There is no shroud around the fans... just the shroud that seals the radiator to the front (since they are push fans, they are mounted on the front side of the radiator, in between the radiator and the nose of the car)

- there is about a 1 1/2" gap between the fans and the radiator (this was just the way that ended up working for mounting the fans)

anyways, i am pretty sure that the cooling system is working (no kinked lines, thermostat working, fans do turn on) as indicated by driving and the temp staying cool, there is just something not working when i stop moving. let me know what you guys think.

-Peter

[budman5201]

I had the exact same problem in 2 of my sub conversions. And both turned out to be a stock subie thermostat that opened up a very small amount and very very very slowly. Take your stock subuaru thermostat out, go buy a cheap aftermarket one, boil some water in a big shallow cooking pan that is high enough to cover both thermostats completely in the water and watch the reaction time of both.

I guarantee the stock subaru thermostat has a slow reaction time and gets suck from time to time. Air bubbles are not that hard to burp.

Oh also the other thing I messed up with on my first subaru conversion is that I eliminated all recirculation lines except for to the turbo and back to the water pump inlet. This isn't sufficient and it causes extremely high temps when stopped combined with the slow opening thermostat.

One way to test if it's thermostat or non enough recirculation lines is to gut out the thermostat and run it gutted wide open but with the rim still there so it will seal.

Best setup was to run a new thermostat whichever brand but new, with one small hole in it to let some air pass buy but definitely small or else it will cool too much in the winter.

That will test if your front radiator is enough and if cruising at highway speeds it should run cold if now at 160 degrees all day in 70 to 80 degrees weather. That's what mine does with thermostat gutted.

[malaga_red75]

I had the exact same problem in 2 of my sub conversions. And both turned out to be a stock subie thermostat that opened up a very small amount and very very very slowly. Take your stock subuaru thermostat out, go buy a cheap aftermarket one, boil some water in a big shallow cooking pan that is high enough to cover both thermostats completely in the water and watch the reaction time of both.

I guarantee the stock subaru thermostat has a slow reaction time and gets suck from time to time. Air bubbles are not that hard to burp.

Oh also the other thing I messed up with on my first subaru conversion is that I eliminated all recirculation lines except for to the turbo and back to the water pump inlet. This isn't sufficient and it causes extremely high temps when stopped combined with the slow opening thermostat.

One way to test if it's thermostat or non enough recirculation lines is to gut out the thermostat and run it gutted wide open but with the rim still there so it will seal.

Best setup was to run a new thermostat whichever brand but new, with one small hole in it to let some air pass buy but definitely small or else it will cool too much in the winter.

That will test if your front radiator is enough and if cruising at highway speeds it should run cold if now at 160 degrees all day in 70 to 80 degrees weather. That's what mine does with thermostat gutted.

So, your saying literally drill a hole in the thermostat to allow flow even when the thermostat is closed? I just want to make sure I understand this right before I go about drilling holes. Thanks budman.

This is what I was thinking too, I actually just called Kohlweiss to see if they had thermostats. I am kind of thinking this might be it because of the fact that I have now pulled vacuum several times from several ports in the system. And also that when revving the engine (forcing more water through the engine) it cools down. Off to kohlweiss to pick up the thermostat and gasket! Ill keep you guys posted.

-Peter