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Well folks, It's official: I'm an idiot.


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I had previously done the throttle body bypass mod on my vehicle, but incorrectly. Instead of reconnecting the removed hoses to each other, and allowing trapped air to move through, I had capped them off, so a small amount of air was held captive in the ends of each hose, and that's all it took to mess up the balance in the cooling system.

 

I reconnected the hoses to the TB, drove the car up on ramps, burped it out, and voila; normalcy. :headbang:

 

Thanks to everyone who helped. Texan, don't worry 'bout the rad-cap, now I got a replacment on hand. The original ain't gonna last forever.

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This probably (guessing here) means most of the gas in the system was well away from heads ana cylinders so I doubt you'd have any seriously overheated ares in the engine.(Unless that's the only place coolant crosses over!) But It is still a weird thing. Why wouldn't the gas just stay up there?

 

HEY! That might be a good place to bleed the system in future coolant changes! You may have discovered a solution to coolant refill problems!

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Originally posted by 1 Lucky Texan

This probably (guessing here) means most of the gas in the system was well away from heads ana cylinders so I doubt you'd have any seriously overheated ares in the engine.(Unless that's the only place coolant crosses over!) But It is still a weird thing. Why wouldn't the gas just stay up there?

 

You know... (long pause)... all I can say is that something in that airplane article just clicked in my head, and when I woke up this morning the answer was there.

 

How such a small amount of air trapped in the ends of those little hoses caused all that relentless boiling in the rest of the system I really don't understand, go figure.

 

I don't think I did any damage, but having said that, I don't think I did my motor any favors either. It's the localized boiling of coolant off of the surface of the jackets which surround the cylinders that effectively reduces actual coolant contact with the jacket, so the bore temp would rise to some degree. I think the cooler 'stat may have been my saving grace by way of greater opening and flow. Not once did the block temp ever rise into an overheat condition.

 

HEY! That might be a good place to bleed the system in future coolant changes! You may have discovered a solution to coolant refill problems!

 

That appears to be what the author of the article did. He tapped petcock(s) into the crossover pipe.

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What type of problems were you seeing? It probably didn't have much to do with air bubbles.

 

That line that goes to the TB also goes to the IAC valve and its bimetallic valve that closes when coolant temp goes above a certain point. by capping those coolant lines off, the valve never really saw hot enough coolant, and it stayed open.....which probably causes high idle. The ECU probably tried to compensate, and probably got confused......

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Originally posted by Legacy777

What type of problems were you seeing? It probably didn't have much to do with air bubbles.

 

 

The problem I was having was an inability to build full pressure in the cooling system which resulted in a constant stream of bubbles (boil) out of the overflow tank. (see thread: "Oh Crap, bubbles in the overflow tank"). I was concerned that I might've had a head gasket problem.

 

 

That line that goes to the TB also goes to the IAC valve and its bimetallic valve that closes when coolant temp goes above a certain point. by capping those coolant lines off, the valve never really saw hot enough coolant, and it stayed open.....which probably causes high idle. The ECU probably tried to compensate, and probably got confused......

 

 

Actually I have no operational problems whatsoever, the vehicle runs fine. In fact it's never run better.

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