Can a cracked reservoir tank cause overheating?

Question

I know I have asked many questions about this 99 Grand Am but today I discovered a crack in the reservoir (overflow) tank. The antifreeze has not gotton to low but I'm wondering could this crack be causing the car to get too hot when idle. I know the tank has to be under a certain amount of pressure. Would this crack affect that? Also, It seems that my thermostat is not opening until the car gets to around 220 degrees and then after about five minutes it will go back down to around 190 and go back up again whenever its idle. It never goes past 220. Never in the red.

Answer 1

apparently this crack is letting some of the pressure in the water system not be enough.the system is designed to hold so much pressure,acording to the pressure cap. and this would have some effect on it...like the rad.cap not being on properly.

Answer 2

Cracked Coolant Reservoir Overheat

Answer 3

The calibrated pressure cap is either on the top of the radiator itself or the overflow reservoir. If it's on the overflow reservoir, then the reservoir has to maintain the pressurized psi (pounds per square inch) of hot coolant pressure needed to raise the boiling point of the coolant to the design levels. Otherwise, your coolant will boil prematurely. Your Engine Control Management (ECM) computer depends on having the engine running at the correct thermostatic temperature. Anything else results in a distortion of the proper sensor and fuel/air ratio mixture necessary for optimum engine operation.

Answer 4

As the water in your engine heats up, it expands. When it expands it needs a place to go. That place is the cracked reservoir tank. Normally as the water cools it sucks the water in the tank back in. In your case it leaks out so when the engine cools down there is no reserve water to keep the system at its proper level. So as your thermostat opens and closes (as it should) you are noticing the sudden changes in temperatures that, if your system were filled properly you would never notice.

Answer 5

it could, having a crack in reservoir tank means that it's probably all leaking out and if the rad needs more coolant, it has no place to get it from. Thus it would make it run hotter. The reason it goes up and down is because after it gets to a certain temp, your fan kicks on and pulls air through it and cools it back down.

I would try to find a new one if I was you and always make sure your coolant is filled up.

Answer 6

Your engine takes a 195 thermostat and normally runs at 210. You're not overheating. The reservoir tank is not pressurized. If you don't get low on coolant, it's not hurting anything.

Answer 7

It sounds like a sicky thermostat. And no, your reservoir tank will not overheat your car,cracked or not. The reservoir is for coolant overflow when your car begins to overheat or for when your coolant leaks somewhere it will take from there.

Answer 8

Is your electric radiator fan working?

Thermostats are cheap and easy. Replace it.

And yes, a broken cooland resevior CAN cause your car to overheat if it has no way to pull in coolant as the engine cools down. All it will do is suck air into the cooling system.

Answer 9

Yes, I had it happen in an older Pontiac. Chronic overheat and it wasn't water pump, fan, thermostat, radiator or cap; found a crack in the tank, replaced it and stopped the problem

Weird

Answer 10

Sounds like it is working normally to me. My Jeep has a cracked reservoir and never gave me any trouble.