Join Now

[gt35rturbo]

And having a steam pocket of air move past the sensor can cause problems on a ecu tune.
Also can cause cavation at the pump and it will tear the surfaces up.

[nil5]

Originally Posted by gt35rturbo

Reving the engine to push the air bubbles out is a bad idea. You can atomize the bubbles into the coolant, This will only appear to have bled the system. Few hours later and you are back to having a air pocket.

The idle with funnel topped up and slowly squezzing the upper hose is the best way. Yes with heater on full as to clear out the heater core. idle it passed a few heat cycles on the fans, make sure the funnel is full and then shut the car off. As the air escapes out the sides of the funnel it will displace it with fresh coolant.

+1 on setting your HVAC temperature control to full hot.

Could you explain the atomization of the air into the coolant again? I have never heard that before, and I'm a little skeptical, since reving the engine is very common practice when bleeding cooling systems.

[gt35rturbo]

Sure as the air gets pulled thru the cooling system the water pump hits that pocket of air. As you idle it, the air can move passed the pump with little problems. The faster the pump moves it chops at the air. breaking the air up[. The faster you rev the water pump it breaks up that air pocket into even smaller bubbles.

Just like when you put some coolant into a can, shake the can slowly, air stays, Shake the can fast and it begins to bubble up and can foam.

Most do know and after a few days the catch tank purges the system, Which is fine, but then you are driving around with a low coolant level in the catch tank and the system cant work correctly when it needs to move fluid back and forth.

This happens a lot when people bleed brakes. pump fast the peddal gets hard, few hours later it gets soft or becomes very hard to bleed. Unless you let it sit for a few hours, then bleeds up quick. When you let it sit for a while the small air moves back into bigger pockets, and bleeds right out.

[Deuce Cam]

Originally Posted by gt35rturbo

Reving the engine to push the air bubbles out is a bad idea. You can atomize the bubbles into the coolant, This will only appear to have bled the system. Few hours later and you are back to having a air pocket.

The idle with funnel topped up and slowly squezzing the upper hose is the best way. Yes with heater on full as to clear out the heater core. idle it passed a few heat cycles on the fans, make sure the funnel is full and then shut the car off. As the air escapes out the sides of the funnel it will displace it with fresh coolant.

The purpose of revving is to get the engine up to operating temp. faster so the fans turn on initially (the procedure is meant to be done starting with a cold engine). The Subaru service manual says to do this fwiw. I'll admit that they probably only recommend it so one isn't wasting fuel.

If one attempts to do this with cold engine it will take forever for the fans to turn on if you don't rev it, like 15-20 minutes.. Once the fans finally turn on for the first time there's no need to rev the engine anymore because it will only take a couple minutes between each fan cycle.

[gt35rturbo]

Originally Posted by Deuce Cam

The purpose of revving is to get the engine up to operating temp. faster so the fans turn on initially (the procedure is meant to be done starting with a cold engine). The Subaru service manual says to do this fwiw. I'll admit that they probably only recommend it so one isn't wasting fuel.

If one attempts to do this with cold engine it will take forever for the fans to turn on if you don't rev it, like 15-20 minutes.. Once the fans finally turn on for the first time there's no need to rev the engine anymore because it will only take a couple minutes between each fan cycle.

Most rev the car to try and purge the system quicker.
A car if the cooling system is working correctly it should warm up the same unless its had a load applied to it. Thats the job of the thermostat. reving doesnt add a engine load. if anything its bad for the top end oiling system as the oil is still thick to move and lubercate the heads.

If your in a rush to bleed a system, maybe you shouldnt be messing with it. Try bleeding a 1st gen mr2..

[BriEE]

I don't understand why or what funnel to put in the top tank while bleeding air?

[gt35rturbo]

Originally Posted by FlashEngineer

I don't understand why or what funnel to put in the top tank while bleeding air?

You put a funnel at the top to displace air. As the air moves out of the system past the sides of the funnel, the funnel then moves coolant into the system. The funnel is just keeping a surplus on stand by of coolant for pockets of air as it bleeds out.

[BriEE]

So just any size funnel or has to be size of the filler neck of the top tank? I hate buying funnels because I just don't know what they were used before and toss them away !

[gt35rturbo]

Originally Posted by FlashEngineer

So just any size funnel or has to be size of the filler neck of the top tank? I hate buying funnels because I just don't know what they were used before and toss them away !

Harbor freight 6 funnels for $3 you want it to be just big enough to fit in the top tank.

[Brettnrs423]

You don't need a funnel although it will help. I have done mine several times without one. You will probably overflow a little and spill some coolant out here or there but just wipe it up when you are done. No big deal.