I opened the yellow coolant cap the one close to the block...And now when I start my car the coolant warning light comes on? How do I fix this??? Thanks

 

Fill up the coolant to the top of the filler neck (when the engine is cold).

 

Do I just keep filling? Because when I put coolant in it stays at the top for a sec then drains down, it's as if it needs a vacum to hold it up there...I just don't want to put too much in...Thanks

 

Don't drive the car until the coolant is at the top and stays there. The cooling system has to be full. If there are air pockets, you'll need to burp it too.

Also, be sure that the coolant level in the expansion reservoir is between the hi and low marks (when the engine is cold).

 

I filled and filled and then coolant camee out near the expansion resevoir, there didn't seem to be a problem, to start with (No coolant light) then I opened that darn cap and the fluid level sucked down and now this...Can somebody please help me? Is there an overflow on the expansion resevoir that would account for the leaked fluid after the overfill?

 

Is it coming out of the expansion tank, and is it full? (It should not be full.) Or is it coming from that general vicinity? I think you need to find exactly where that coolant is coming from. Hopefully it's not the radiator...

You can see the top of the expansion tank by removing the neck (1 bolt). The neck is only loosely set into the tank. Excess coolant can spill out from there or from a small relief hole in the top of the tank if it's full.

 

Okay, I filled and filled and it overflowed, wait I said that already, then while it was at the top before it sank down I put the cap on. Must be a vacum of some sort. Started the car and no coolant light. No leaks from the hoses, the AST is full, the radiator is full, pulled the plug in the bottom. all lines are connected and leak free. AM I OKAY TO DRIVE THIS THING? I took it around the block after initial warm-up, and the PFC commander was reading steady @ 80 deg. C....

 

It's full, it's way above full on the dipstick and is drippinig from that vicinity, because it's none of the hoses and and it's not coming from the radiator I am lead to believe that I overfilled and dumped coolant out the relieve on the expansion tank. Could you confirm for me that the fill cap acts as a vacum and that when the lid is on it holds the coolant at the top of thte fill neck and the more I pour in the more that is going to comoe out the relief...Good grief, had the car 4 days, I suck, I hate not knowing how things work...Thanks Again

 

The coolant expands as your engine heats up, and the pressure cap releases some coolant out into the expansion reservoir (hence the name).

After you shut it off and the engine cools down, the coolant contracts and creates a small vacuum in the cooling system. The pressure cap then allows coolant to be sucked back in from the expansion reservoir.

Any time you open up the cooling system while the engine is still cooling down, you'll break that vacuum. This will prevent some coolant from returning to the cooling system, and it'll accumulate in the reservoir.

Does that help?

 

After some thought I think what happened was I didn't have the AST cap on tight, I was poking around in the engine bay last night checking out what's what and then I took off the yellow cap, without vacum the coolant surged down to the overfill tank, becuase well (**** runs downhill, plumber told me that once). Anyways I didn't get the AST cap on tight till I had already dumped a gallon of coolant on my feet through the overflow on the overflow tank. Tightened the cap, filled the neck replaced the yellow cap and started the car. She purred for the rest of the day at 95 deg. I never had an overheat issue, the coolant sensor was just exposed to air becuase I lost vacum. Thus when I went to start the car I immediatly get the warning light. Fill the neck( which covered the sensor) vacum is back and i can sleep. This car is going to give me grey hair. Am I on the right track with all of this? The engine only has 3k miles on it and I am already worried about rebuilding it....To bed with me.Good night

 

I'm going through the exact problem you went through.

I just bought a new AST and cap so fingers crossed my coolant will stop spilling out from the overflow.

 

I would probably buy a new AST cap for cheap insurance.