I drained and refilled my GT engine and intercooler coolant systems. The Airlift vacuum/refill tool does a good job of evacuating the air from the system. However, it still leaves 15% of the air in the system, based on the Ideal Gas Law, PV=nRT. At my altitude of 2000 feet above sea level, the atmospheric pressure is 27.8” Hg. The Airlift draws a vacuum of 24” Hg (at sea level of 29.9” Hg, it should draw a vacuum of 26’ Hg). Given that V=Volume, R=Gas Constant, T=Temp stay the same before and after evacuation, the variables are P=Pressure and n=Amount of Air. So….. n1/P1=V/RT and n2/P2=V/RT. V/RT is equal in both cases so….. n1/P1=n2/P2. Therefore…… n2=n1P2/P1. Given this last equation, the amount of air left in the system is proportional to the before and after pressure in the system. So…… P2/P1 = (27.8-24)/27.8 = 13.7 percent air left in the system. This is important, since both the engine and intercooler radiators, for some reason, locate the inlet on top and outlet on bottom. As a result of the top in, bottom out flow, some of the air remaining in each system most likely will get trapped in each radiator. Although, if people are not having overheat problems, maybe it does not matter, until that hot summer day sitting in traffic. Or, it is possible the flow velocities are high enough to carry the air out. The OEM air bleed petcock on the intercooler radiator will bleed the air, but it is not readily accessible with the front fascia installed. The OEM air bleed petcock tabs on the engine radiator are so long that they hit the radiator hose; therefore it can barely be loosened.
To remedy this bleed issue, I installed a readily accessible bleed line on each radiator. I had removed both fenders to replace the windshield, so removing the front fascia at this point was simple. To easily bleed the radiators at any time, I just loosen or open the degas bottle cap and open the now readily accessible bleed caps to vent the air. See Pics attached. It is so easy to bleed the air that I did not use the Airlift refill evac tool to refill either systems. Pouring in the coolant with the air bleeds open was easier. It does take awhile to gravity refill, however.
I very carefully measured the coolant removed and replaced. In addition to draining from both radiator drain cocks, I disconnected hoses and removed the engine drain plugs in order to be sure everything was empty. I even tipped the car to empty the horizontal tubes. I removed 4.7 gallons from the engine system and 1.7 gallons from the intercooler system. The engine took 5.0 gallons and the intercooler took 2.0 gallons to refill. Could the additional amount required to refill be due to air trapped in the radiators? Very possible.
Material List of Parts - Earls Performance Items
3 - 600133ERL – Hose End, Straight
1 - 609033ERL – Hose End, 90 Degree
2 - SS981603ERL – 1/8NPT to 3AN Adapter, Straight, Stainless
1 - 6100031ERL – 3AN PTFE Stainless Braid Hose
2 – SS983203ERL – 3AN Bulkhead Fitting, Stainless
1 – SS592403ERL – 3AN Bulkhead Nut Stainless, Pair
1 – 592903ERL – 3AN Cap, Pair
To remedy this bleed issue, I installed a readily accessible bleed line on each radiator. I had removed both fenders to replace the windshield, so removing the front fascia at this point was simple. To easily bleed the radiators at any time, I just loosen or open the degas bottle cap and open the now readily accessible bleed caps to vent the air. See Pics attached. It is so easy to bleed the air that I did not use the Airlift refill evac tool to refill either systems. Pouring in the coolant with the air bleeds open was easier. It does take awhile to gravity refill, however.
I very carefully measured the coolant removed and replaced. In addition to draining from both radiator drain cocks, I disconnected hoses and removed the engine drain plugs in order to be sure everything was empty. I even tipped the car to empty the horizontal tubes. I removed 4.7 gallons from the engine system and 1.7 gallons from the intercooler system. The engine took 5.0 gallons and the intercooler took 2.0 gallons to refill. Could the additional amount required to refill be due to air trapped in the radiators? Very possible.
Material List of Parts - Earls Performance Items
3 - 600133ERL – Hose End, Straight
1 - 609033ERL – Hose End, 90 Degree
2 - SS981603ERL – 1/8NPT to 3AN Adapter, Straight, Stainless
1 - 6100031ERL – 3AN PTFE Stainless Braid Hose
2 – SS983203ERL – 3AN Bulkhead Fitting, Stainless
1 – SS592403ERL – 3AN Bulkhead Nut Stainless, Pair
1 – 592903ERL – 3AN Cap, Pair
