Pontiac Grand AM coolant leak

My coolant appears to have dumped out of the release hose in the coolant reservoir. I’m talking like at least half way full. The cap was still on and the car temperature was normal when it happened. Is there anything that can cause that much pressure and how? Also for some reason in between the time I the coolant dumped itself out of the hose and I made it to my destination in the middle of a turn I completely lost power steering. But then a few seconds later it went back to normal.

When was the last time the serpentine belt was replaced?

The belt may be slipping causing the water/power steering pump to slow down.



Pontiac Grand AM GT MYSTERY coolant reservoir tank leak repair fix Alero Impala Malibu Grand Prix - YouTube

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I replaced the serpentine belt about a year ago when I got the power steering pump replaced. I also replaced a couple of the original pulleys when I did that.

I appreciate that I still have the stock reservoir so i will definitely check that out.

So I found a small crack on the bottom. Nothing like what was in the video. I think that could do it though when I think about it. Air could still get in and cause the coolant to bubble which would then cause the coolant to rise and escape the the release hose. I’ll replace this and hope it works. Luckily the gasket isn’t the issue sense I’ve had the replaced about 2 years ago.

The loss of power steering was likely from the coolant splashing onto the serpentine belt. Coolant is more slippery than water.
I would be tempted to just replace the cap, but a new reservoir is less than $50, that might be the best way to go.

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I have replaced the caps twice before. I would be happy if it’s just the reservoir cause that sure beats having to get a new radiator or something else expensive.

The cooling system in my sons Pontiac would not hold pressure, the previous owner replaced the can, reservoir needed to be replaced. The coolant will boil if not under pressure, the system pressure raises the boiling point 45 degrees.

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I’ll keep an eye on it. Appreciate it. Im gonna give it a few more days with driving to make sure the same thing doesn’t happen before I say it’s fixed.

When you say holding pressure do you mean water/coolant coming out of the pressure release hose whenever the car is not accelerating?

The head gasket could be starting to fail. If it’s this it should be worse at full throttle. It’ll put engine gasses in to the coolant which will make it overflow.

Otherwise maybe the electric fans failed and it started to overheat? Does your temperature gauge show the actual temperature or does it lie and just go to normal or all the way hot?