Wilhoit Anti Drain Back Valve

[Kevin Saunders]

If you want to reduce smoke on startup, let the car idle until the level gauge stabilizes before shutting down. Works for me. Save the $$$$

[MrBonus]

WR Anti Drain Back Valve KIT for 65-71 911 - Willhoit Auto Restoration

Does anyone have the full kit? My line to the engine-mounted cooler is leaking so I think now is the time.

[mo-mon]

Originally Posted by Kevin Saunders

If you want to reduce smoke on startup, let the car idle until the level gauge stabilizes before shutting down. Works for me. Save the $$$$

This works for me.

[pampadori]

So there is the Rothsport $$$ valve, and then this WR anti drain back valve for fewer $$.
What do we think about the less Porsche specific check valves? Like Vibrant part number 11196 (uses -16 male fittings instead of barbs but its ~$50

[7783911]

As some have stated, risk versus reward. My Porsche mechanic (used to be with Porsche Racing NA) was adamant that it should not be used for the simple fact that if it ever failed for some reason..your kaput

[Mark Henry]

So he's never tried one, has he even had one in his hands?
The only fail mode is wide open.

Think of the valve being like a tiny toilet plunger, with the handle being a solid shaft riding in a brass bushing, so the head (valve) can't cock, it can't go anywhere but in and out. The spring is very light, I'm surprised it can even hold back the oil in the tank. The head is a cone, between the suction of the pump and gravity working on the tank, the valve has no option other than moving open with the flow.
Like I've said, I've seen no hesitation on either my gauge or idiot light since installing my RS valve.

Having to check the engine while running as recommended, tells you that Porsche knew a lot of oil is migrating into the engine sump.
One big bonus of this valve has been the ability to check the oil when the engine is not running.