Charzardbolt

I've been having reoccurring issues with my coolant system for 2 years 2010 g37x 101000 miles. Constant coolant leaks, always in a different place as last time. I think its a head gasket, but its not that bad, no issues with A/C or heater. No problems with oil or coolant mixing. Just increases pressure in coolant system which causes hoses to blow or just slowly leak. I've bled the system multiple times, replaced all the hoses. Replaced the heater core,but it keeps happening. Is there anyway I can add a coolant air release valve to have a constant vent of air, but not coolant? I know this is a bandaid for the real issue, but I don't have to skill or the money for a head gasket.
Edit for the mileage

Birdie

No on the coolant release valve. Has to be a sealed system to get it from boiling too soon.

Have you tried changing your radiator cap .when the system builds pressure the cap should open to allow the excess fuild to go into reservoir keeping pressure in check as the fuild expands.

Osama_STI

I have changed radiator, all hoses, radiator cap, and thermostat and the pressure still high when i open the radiator cap after a trip. The expansion tank gets full and I have to empty it into the radiator every other day.. its been happening since I got the car 2021.. when the car overheated i took to the shop and they told me that the gasket is good and no problem with the engine! I dont really know what to do anymore!

socketz67

The system takes two gallons of coolant. The thermostat holds the fluid back until it reaches a temp of 82°C (180°F). Once that happens, you can squeeze the lower radiator hose and feel the coolant passing. An OBDII reader will also provide an indication of when the coolant reaches operating temp. Now that it has reached operating temp, the radiator cap controls expansion (hot) and contraction (cooling) into the reservoir as the water pump circulates coolant through the heads which returns to and from the radiator as part of the normal flow. When the car is cold, the coolant in the reservoir should reside in the middle of the upper and lower lines noted on the outside of the reservoir. When at operating temp and while cooling, the system is pressurized. Do not take the radiator cap off.

These cars are extraordinarily picky about air in the system, but if you use a spill free funnel and run the heater while bleeding, you will eventually see no bubbles present in the funnel. Took me 20-25 mins to clear all the air.

It's a fairly straight forward process to this point.

However, if a head gasket is leaking, that could allow combustion gases to enter the cooling system.

While I have never used one of these myself, I know that one way to test is to rent a block test kit from Autozone: https://www.autozone.com/loan-a-tool...-gasket-tester

A DIY test for a leaking head gasket is to remove the cap to vent any pressure when the engine is completely cold (i.e. after sitting overnight). With the cap back on the hoses will now be soft. Drive the car until it reaches operating temp, then let it "completely" cool down again. If the hoses are hard, then air is likely being pumped into the cooling system. An alternative test is to fully bleed the system, drive the car, and re-bleed. Release of a significant amount of air on a re-bleed is also evidence of a head gasket leak.

Osama_STI

I use the vacuum refill kit! Is that even good enough? I dont do anything after that.. I simply close the cap after its full and start to drive.. you think there is still air in the system after that?

every 2 days, i have to open the radiator cap in the morning and I refill by hand water from the expansion tank back into the radiator. The amount of water is the same indicating that there is no leak at all..

to add coolant I vacuum the system and the system holds it as long as i keep it, the gauge’s needle doesnt drop even a millimeter .. when I do pressure test, the system holds 20psi with no any leak as long as i leave it in..

when I open the radiator cap after 2 days there must be a btchooo sound, I think its pressure though!

I think when the car is hot and running it creates pressure , that pressure causes overflow, that overflow goes to expansion tank. when the is parked, the coolant cools down creating vacuum to pull the part of the cap down in order to refill radiator with the overflowed water. Is that how it works?

rotarymike

iTrader: (4)

Bingo!

If you're getting constant pressure displacing the water into the expansion tank, I'd seriously consider looking for a head gasket pinhole failure. Do a leakdown test on the cylinders.

If that's good, then somethings' messed up with your overflow/radiator cap piping. Could the line from the thermostat to the overflow be pinched? It might be open enough to let pressure through, but vacuum itself shut when the engine cools.