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Boiling in my coolant reservoir

So I just recently started getting my coolant to boil over. My temp gauge never overheats, and I just had the radiator, clutch, and thermostat changed to possibly fix it. The coolant has been tested for a blown head gasket, and it passed. Threw on a new coolant cap, and just about got all the air out of it. It’ll start to boil when I’m driving, and when I’m done driving, it’ll overflow. What else could I be missing?

I’m still betting it’s a bad head gasket, the coolant isn’t boiling, it’s bubbling as the exhaust gasses are pushed through it. Or it’s air trapped. Did you have the system pressure checked?

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You can get a kit like this:

to rule out HG exhaust leak into the coolant.

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If it has an automatic transmission, check the color/smell of the fluid.

image

Tester

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