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Hey guys, if there is air in the system will the thermostat not operate correctly? You know how I have been complaining about this fan cycling issue lol. Lets review what has been done. 3 temp sensors now on a brand new OEM temp sensor. Tried 2 thermostats. Tried 2 rad caps. Tried a new rad. Recently swapped the turbo, replaced rear cam support seals the 2 red and 1 black seal. Tried a wrx coolant tank. What else is left?! Yes let me guess headgasket.

What I don't understand is why my temp guage I can actually see moving noticeably lower then the middle yet the CTS is telling the ecu the temperature isn't dropping. With my laptop plugged in i will maybe show 94C needs to go to 89C to shut off the fans. If I rev it to 2k after maybe 20-30 seconds they usually shut off and I can see the temperature begin to drop. So the temperature is reading. What is unusual is if I go outside the fans are blowing freezing cold air which is telling me the thermostat has already closed up fully.

This problem is like killing me because I can definitely feel the car doesn't perform exactly like it does when the fans are working. The only time I can get them to cycle on then turn off while driving normally is if I let the car idle right till it warms up. Still sometimes might cycle on and stay on! So electrical issue seems to be eliminated. There are no signs of headgasket. No bubbles in overflow. Coolant always looks clean when I drained it. Water pump was replaced and to be honest I don't know if it did this stuff before since it was a short period I was driving the car till the original water pump started leaking. It was oem and had the OEM metal gasket.

No coolant leaks either. Maybe I should go for the exhaust in coolant test?

Am I not bleeding the air correctly? I am thinking maybe I should point the nose forward a bit maybe and try burping the system again since the coolant tank is up high and towards the back off the motor.

Any other concepts?!! Car doesn't get any worse or any better no matter how much money I throw at it. (acutally with the new turbo and IC definitely goes much faster). Will probably never give up and in the end will be something stupid and simple causing my issue like everything else... haha I would be so bored without a Subaru...

Tomorrow maybe I should try to burp it then drive for a bit and see how things work out. I think my issue might be related to the overflow coolant lines. Maybe its sucking in air when I shut it off and it cools?

Almost positive it's a head gasket in the earlier stages. Seldom will you see oil/coolant mix in either direction nor air bubbles (I've never actually seen it). What seems to happen is air collects by the thermostat housing, as you suspect, which can mess with the thermostat and also cause the water pump to cavitate. When you vary engine speed, you vary water pump speed, which helps break up the bubble in the pocket. Right now, there's not enough air completely isolate the water pump. The beginning stages of that will be when the car starts to get hot at steady speeds (air build up). A temporary fix to get home would be popping the thermostat out and stopping every once in a while to squeeze the hoses, forcing coolant around to displace some of the air and at that point you should be able to bleed it out of the radiator.

I'd tend to agree with Steve.

Are you losing coolant at all?

nope no coolant loss. Never once seen the guage go anywhere about the middle mark. I have tracked the car too with no issues. lets say I don't have a very light foot DD.

If I drive the car aggressively and I get out and wait. The fans will turn on for 20 seconds shut off and continue to cycle just fine. If I just drive normally its a come and go situation.

Another question with the cap off if I let the car idle to warmed up is it normal for some coolant to come up?? I guess its the same concept with the rad cap on and it releasing that fluid into the overflow.

Next year when my dad finishes building the garage I will replace the headgasket if the issue continues.

So I will leave the issue as a TINY TINY headgasket leak.

Going to replace the overflow lines. I have a funny feeling it might be my issue. Possibly the lines are leaking. The metal lines are very rusty as well. Who knows if I punchured the rubber anywhere last time I touched the lines to clean them.

Is it ok to buy the right size coolant hose then just run it from the coolant tank right to the overflow instead of using the metal line which is all rusty?

ericem wrote: Is it ok to buy the right size coolant hose then just run it from the coolant tank right to the overflow instead of using the metal line which is all rusty?

Yes, but that rust is probably just on the outside, so I really wouldn't worry about it too much.

The best way that I have found to burp it is to take the car for a drive in a hilly area. I usually try to stop right as I'm heading up a hill and then floor it to help slosh all of the coolant to the back of the engine. Then speed down the hill and "slam" on the breaks to slosh all of the coolant forward. Then make a few high-speed turns here or there and then check the coolant tank. If there were air bubbles, they've more than likely been dislodged. Top off the tank and repeat.

It's a crude method, but hey, it works. Sometimes an air bubble gets stuck right at the thermostat. You can tell if it's there because the lower radiator hose with be hot where the air bubble is, but cold every where else. Try giving it a few squeezes.

I hope so

Everyone thinks I should live with it. but its sooooooooo annoying getting out hearing my fans running all the time. The car never overheats EVER no matter what I do. Traffic for 2 hours you name it! Going to try your air bleeding method. I do hear air though in the heater core when I take off I can hear swooshing!

lol found a few hoses i forgot to put clamps on as they were hiding under my bpv hoses. why does the coolant overflow with the cap off like right away such a pain in the ass. Shouldnt it technically go in the overflow ?

More myths so after driving today like usual fans don't cycle ya hte story of my life!

Today after driving a while got out fans were cycling. Turn on for 15-20 seconds shut off like I should. This time it was different because the upper hose didn't feel pressurized well it did slightly but not like hard as a rock kind of pressurized, and the overflow was at a higher level then usual. Drove around still worked fine. Drove some more. BAM fans don't shut off hovers at 199F and that upper hose is completely pressurized.

Does this mean its my rad cap not relieving the pressure??

iMan, this is turning into a career isn't it?

Have you checked the bottom hose isn't soft and sucking shut with revs?

Are you sure the water circulates through the heater properly? That is, with a full flow?

Is this an auto? They can speed up the idle and run the fans if the auto is getting hot.

lol guess what was driving big puff of smoke. Lower coolant hose going into the rear cam broke!! So got some heaterhose and replaced it. No more leaks and no more damn coolant smell when I get out.

I tried to bleed the system but I can't do it!!!! The thing starts overflowing once it gets warm. Is that normal??

Which hose was it? Did it crack from fatigue, or burst? It's really starting to sound like head gasket issues...

It broke because I am hard headed and after removing the cam support and seeing and feeling the hose was garbage I still put it back as soft and fragile as it was!

I just need a straight answer with the overflowing while warming up with the cap off. Is it normal?? Just ignore it and let it overflow till the thermostat opens then I can top it up and put the cap on ??

Yes, it's normal for it to overflow. I'd suggest putting the cap on, let the car warm up and squeeze the top and bottom radiator hoses to help get rid of air pockets. Take the car for a drive so it removes more of the air pockets. Drive back to your driveway or where ever, pop the hood, squeeze the hoses again and then shut off the car. Now remove the cap. If there was air in the system, the coolant level will be noticeably lower. Repeat this process until the coolant level remains full.

I tried that the level when I remove the cap is always full. The system pressurizes full pretty quick. Not sure if its just the rad cap not releasing the pressure? But I definitely can not squeeze the hoses as they are very hard since they are pressurized. Funny how when I found that hose leaking the fans were cycling and the hoses were not full pressurized...

If they're pressurized then that's a good sign. That means you don't have any leaks.

ok, so wtf won't the fans cycle. Also if I am cruising down the highway. Just hovers around 200-210F. If I floor it will start dropping then eventually go up. After enough consistent driving will go to a steady 190F. The car definitely feels faster when the temp goes down to the 190F range.

You must have an air bubble somewhere then. You can buy a funnel with a radiator cap attached to it to help you burp the system.

http://www.drivewerks.com/catalog/shopc ... 91_pg2.htm

Basically you just attach this and then fill it with anti-freeze and squeeze the hoses/rev the engine (to make the thermostat open quicker) and if an air bubble pops up, it'll allow it to escape but won't allow more air in.

thats exactly what i need! Lol going to get one after school.

Can anyone believe the motor that had fans that cycled perfectly that was in my wagon that is NOW in my 94 SS does the exact same thing with the fans not cycling? WTF!!!!!!!!!!!! Only thing I changed was the thermostat before swapping in the motor everything else coolant related I left original. Only other component that is still original is the heater core!!!!

It is UNBELIEVABLE!! lol 2 motor's same exact issues with the temps wanting to hover to high with the fans running.

Just a refresh the fans cycle off at 190F and the fans turn on at 203F. So lets say they cycle on, the temp won't drop but will stay at 203F maybe hit 198F. I need to rev the engine, like not high RPM's but I need to blip the throttle.

My dad thinks I should buy this device that attaches to the rad cap that acts like a funnel so I can let the car run for a while and bleed any bubbles.

Yeah....sounds like air....or a bad pump.

I didn't touch the pump since it has been in the other car and it worked PERFECTLY in the other car it's crazy. I am thinking of trying this to save $40 for that rad cap funnel thing.

http://autorepair.about.com/library/faqs/bl192i.htm

That sounds like a good idea. I'd just make sure to take it out when you're done.

I used one of those funnels and it worked beautifully. Just squeeze the radiator hoses and push down on the front and rear bumpers while it's attached to help work out the air bubbles.

you need that funnel to bleed any car right, also you just put the funnel on and let it run heater in the car off and when the fans kick on take it off and put cap on your done.

let me know where you find one becuse i have one and only the snap-on guys i thik sell them.