How to make your leaky stock 3000GT/Stealth blow off valve (BOV) seal in five minutes for a couple bucks:

Before you go spend hundreds of dollars on a shiny aftermarket blow off valve for your VR-4 that isn’t going to help you much anyhow, consider this quick hack that will keep your factory BOV from leaking. It takes about five minutes and is virtually free!

What you need:

• Factory 3000GT/Stealth BOV
• Neoprene washer (1.5″ diameter or more)
• A sheet metal screw and matching screwdriver
• Scissors

The sheet metal screw should have a large domed head and be sized so that it will thread into the plunger shaft of the BOV (the hole in the below image). The screw I used was found somewhere on the chassis of a 3/S, and most people should have a few kicking around (or consult a hardware store). The neoprene rubber washer can be found at any decent hardware store. Make sure the outside diameter is at least 1.5″ in diameter and the hole in the center is smaller than the head of your sheet metal screw.

BOV inlet (plunger face) - note the hole where the sheet metal screw will go

BOV outlet - fiddle with the plunger to see how it works

How to fix that leaky BOV:

1. Blow into the BOV inlet. Witness leakiness.
2. Trim the neoprene washer a bit larger than the inside diameter of the inlet tube, keeping the hole centered (below)
3. Stuff the washer onto the plunger face and depress the plunger while lining up the hole (it may take some fiddling)
4. Thread the sheet metal screw into the hollow plunger shaft and tighten it down
5. Test the BOV to be sure the plunger moves and blow into the inlet (when closed) to make sure it seals

Trim the washer a touch larger than the BOV inlet

The finished, non-leaking BOV

Folks, it doesn’t get any easier than that, and until you have big turbos and run loads of boost, this will do the trick. Note that this only works with 1991-1993 first-generation (1G) BOVs because of the accessable plunger face, but a 2G car can use a 1G BOV with a 1.5″ 90 degree elbow, stubby piece of hose, and a couple of hose clamps (which can all be found at most hardware stores).

Technorati : 3000GT, BOV, Stealth, Turbo, VR-4, blow off valve