# Coolant PRESSURE Gauge



## Poncho Dan (Jun 30, 2009)

Yes, coolant pressure, as a dash/panel gauge. Does such a thing exist, or would you have to find a digital oil pressure gauge? Figure the coolant system is rated for 18PSI, so 20 is the max you'd need for a gauge scale. I always thought it would be useful in case something suddenly popped from fatigue or there were a small leak...


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## GM4life (Mar 18, 2007)

I thought you was in school you haven't went over the basics yet? J/K
I never heard of or seen a coolant pressure gauge. Doesn't mean it don't exist. I think you are taking about two different things here. Both I think is hard to measure or no reference point to base it off of. 1) you have the coolant fluid pressure what is going to vary with RPM and thermostat position. Pressure(depends on how you measure)is a measure of restriction fluid flow in the engine is pretty much free flowing 2) Pressure requred to lower the boiling point. As pressure increases boiling point increases. As the coolant temp rises and falls so does the pressure. Coolant mixture also has an effect on boiling point. Since there is two different coolant systems out there both are on the GTO, one has a pressure surge tank and the other has an overflow. So how would someone know if there is something amist with their coolant system? Sorry to say the only way to prevent some coolant mishaps is regular PM. Thats how I wrap my head around your question, its been years since I've went over the basic coolant system operation.

BTW: Now that I think about it. A sensor in the pressure cap would be a good idea to assist with diagnosing proper cap operation. Let you know if your pressure cap is working correctly.


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## Poncho Dan (Jun 30, 2009)

Well, I would assume that your pressure would eventually drop to zero with a leak. It's more of a safety net just in case. PM requires replacing hoses only if they appear to be damaged or dry rotted... there may be an internal flaw that might magically reveal itself in a hose during a trip down the 1320.


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## GM4life (Mar 18, 2007)

You can tell if your hoses is going bad by squeeing them. If they feel mushey then its time to replace amoung other things. Also if you have leaks you can tell by anything else, drops on the ground. It's pretty obvious if your blow a coolant pipe, why I would need a gauge to tell me that? By that time its too late. Its not like an oil pressure gauge that will tell you if you have some type of internal falure before locking the motor up, thats not that obvious on the outside.


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## GM4life (Mar 18, 2007)

I just remembered that we have low level coolant sensors on most of our diesel equipment. Once the coolant gets apporx two inches below the filler neck the unit shuts down. You can probley do something simular with running a low level washer sensor like what is used in some cars in the coolant surge tank or overflow w/ an idiot light.


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## Poncho Dan (Jun 30, 2009)

Good idea... could be integrated into the gauge as a light maybe? This would all be custom stuff anyways, looks like. I'm thinking too, a pressure gauge would show an internally popped head gasket. Think of like a coolant leakdown tester that's on the car 24/7.


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## GM4life (Mar 18, 2007)

Your pressure would be all over the place. Its easy to tell if you have a blown head gasket, when the engine is running. Also if you suspect you loosing coolant, you can pressurize the system.


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## gurvinerjeff (Jan 9, 2009)

*Pressure Gauge for Radiator*

I have a pump used to test coolant systems and pressure-caps for leaks. I bought it so long ago I do not remember where. In one method, the radiator cap is attached to the pump and the gauge shows the pressure it will hold. Older caps held about 15psi. If the cap did not hold the pressure marked on the cap, it was replaced. This pump has a second test method - to pressurize the cooling system to check for leaks. Simply pump it up to the cap release value and watch for leaks. If there are no leaks, the guage stays constant. Of course, this gauge only reads pressure when the pump is installed on the cooling system. I find that is enough for me. You may be racing the car and want to see pressure loss immediately while driving. Good luck. For those who said the pressure can vary all over the place, isn't there are pressure release cap that feeds to overflow tank? It think the cooling system pressure works like my wife's pressure cooker - it holds pressure to reduce evaporation at high temperatures and to increase the coolant boiling point. The car cooling system, once warmed up and pressurized, should maintain a constant pressure until the engine is shut down and the system begins to cool.


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