If you still have the old ring, compare the new ones to it.
The next part is hard to do, but posible - Does require "smoke and mirrors"
You'll need a strong flashlight, a pen light will work, a dental mirror or a small shaving mirror.
Your best friend, with a some time to trade for a couple beers afterward.
2 1/2" bolts or screws that each fit tight into the holes of the new rings.
Shine the flashlight into the valve hole, hold the mirror so that you can see the "bottom" of the hole.
You can hold the bolts up to the mirror where the hole is seen and "match" the diameter
Carefully slide eade each bolt into the hole, starting with the smallest diametr bolt. When you get to the bolt that doesn't go as far as the previous, you have the "correct" size.
You are now down to 2 rings to use. The last bolt you used and one before it. Start with the larger of the two.
Check that the sealing "wax" is not stripped from the threads on the EGR valve, if it has been rubbed off, wrapp the plumbers tape one time around the threads with an overlap of about 1/16 - 1/8 inch, the "top" flap should face left or the opposite direction of tightening.
If the ring goes into the valve seat before the EGR valve, make sure it's sitting flat. If it sits on the EGR then goes into the seat don't let it drop or get bent before putting the ER on.
Make sure you have the EGR Valve Gasket too.
Wednesday, November 26th, 2008 AT 11:26 PM