Application: Porsche® 928, 78-95 all
The Low Pressure Cap
If your 928 is 20 years old or older, and still using the stock radiator and/or the stock plastic coolant reservoir, it may be time to back off the radiator system pressure a tad.
The cross-tubes in our Behr radiators grow weaker with age and can burst, and we are starting to see more radiator side tanks and expansion tanks crack also - all from the age of these components while still trying to run pressure designed for the car when it was new (13 psi)
Replace that OEM radiator cap with one of our new LevRvent-style caps at 7 psi and save yourself a boat-load of headaches and expense later. 7 psi is plenty for the early cars, still prevents it from boiling over, yet is al lot gentler on the cooling system. The lever on top provides positive latching when closed, and allows safe releasing of pressure without water-soaking your clothing.
The High Pressure Cap
Best for Supercharged or Modded or Race Engines. Heat is a byproduct of work performed, the more HP you produce, the hotter your engine will become.
The first place that water boils in most engines is in the head right around the exhaust valve seats, and is often the insult that causes a failed head gasket. Should the water boil in a pocket like around the exhaust seat, the steam generated is very high pressure and frequently at the root of many a post race/DE-day head gasket repairs.
The pressure of the coolant system (provided by the radiator cap) and the ethylene-glycol are the two items at work to raise your boiling point to prevent this from happening. And if you have a race car - the glycol is gone and the pressure in the system is all you've got.
If you have replaced your plastic-tanked radiator with one of ours, then you can safely add a 20 psi radiator cap. The extra pressure will add a margin of safety to your supercharged or race engine to prevent the coolant from boiling. A 16-lb. cap will raise the boiling point 48 degrees higher than the normal 212 degree boiling point. A 20 pound cap adds another 12 degrees to the boiling point.
Both our all-aluminum radiators and our coolant reservoirs are tested to 37 psi before shipping. They can operate at 20 psi indefinitely without harm.