GM 3.6L VVT PCV restriction fix -

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Offline goodfellow

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GM 3.6L VVT PCV restriction fix -
« on: May 16, 2018, 03:48:02 PM »
This "traction control" problem is mostly due to oil vapors gunking up the throttle body. The vapors accumulate in an oil trap in the intake tube and that was VERY dirty with oil; more-so than usual.

The problem obviously lies with the PCV system -- specifically the PCV valve gets clogged; which in turn increases crankcase pressures, and forces more oil vapors into the intake trap.

The solution is to replace the PCV valve (a $18 part at NAPA), or mod the current valve to be less restrictive and cure the problem once and for all. I chose to do the latter.

The PCV valve is located on top of the RR cylinder bank (the one closest to the firewall) -- right behind the throttle body. In fact once you disconnect the intake tube for cleaning, you can see the PCV valve close to the firewall. It has a hose attached that connects it to the top of the left cylinder bank. The hose connection to the left cylinder bank is difficult, so I only  disconnected the PCV connection which has a simple push-in disconnect.

To get it out I used a body clip tool to catch the valve under the lip and lever it up and out

The valve has two breather holes on the bottom end and one of the two holes was clogged with carbon -- hence my oil vapor problem.

shining a light underneath it shows the restriction -- one hole is closed and the other one is partially open

The fix is to drill all the holes out with a 3/32" drill bit -- and then clean it out with lots of carb cleaner solvent.

Shining a light under the valve shows that this fix makes the passages much less restrictive -- and is considered a permanent fix.

Everything cleaned up and res-installed and this fix will go a long way to keep the oil out of the throttle body and prevent the dreaded traction control stall and power drop problem.