Oil Soaked Knock Sensor

[C5NGAGE]

Anyone had experience with DTC P-0327
and finding oil seaping into a knock sensor from the
valley cover grommet?
Working repairs now could use your experience

 

[c4c5specialist]

Hi there,
There is a TSB in the knowledge center here on the CACC, that explains some of the causes behind the P0327. However, with the oil that you are stating on this, I would be curious why the oil, because normally, those seals do not leak, unless disturbed previously.
I would really not replace the knock sensor, unless the sensor connector itself is oil soaked, and oil got inside the connection. Please reference the attached, and let us know if it is coming down the wiring harness, or from the cover.
Now, as for the repair, just remember, installation of this is critical.
I usually coat the seal with a little dielectric grease, to ease installation.
Please reference the service manual for the correct torque specs on the valley cover when reinstalling the cover.
Let us know if we can assist further, c4c5

 

[C5NGAGE]

I would really not replace the knock sensor, unless the sensor connector itself is oil soaked, and oil got inside the connection.

So glad you had time to reply. I can assure you the oil has penetrated the connector and the inner working of the sensor.
The rear sensor has a light grey foam rubber seal at the pin that plugs into the connector, on the front sensor that grey foam is wet with oil and black. Under the rubber seal on the connector there was oil. In the bottom of the valley cover grommet there was about 2 tablespoons of oil. In the bolt hole that the Sensor was removed from I took 4 Q-Tips loaded with oil out of the bottom of the bolt hole.
The rear sensor was nearly dusty while the fronet sensor and all the components around it were wet with oil.
however, the top of the valley cover was dry???
I owned the car since 4,000 miles and have no record of any work in that area being performed. However, the warrenty record does indicate the previous only had the engoine replaced and had an intake vaccum leak repaired.
I have ordered two new grommets, valley cover gasket, Water line bypass gaskets ($20each), I already have a new sensor and new connector spliced into the harness.
Realted to my other post I ordered the oil consumption version of the PCV valve.
I had already sent you the cars history several months ago, form another forum discussion on my transmission.
I sure do appreciate your time and knowledge.
Searching for the where and why in this one.
One big why is why the dealers down here couldn't have found this at 60,000 when the DTC started to come on. I had the GMPP till 75,000, Now at 80,000 its on me to fix.

 

[C5NGAGE]

FIXED IT

I ordered the parts and received EXCELLENT help form the GM parts guys, they know a lot of whats is going on.
I replaced the lower Valley Cover grommets with new. Mind were rock hard and one had signed of misalignment during a previous install. The new ones are soft, pliable and rubbery. Also had 5 Q-tips loaded with oil from the bottom of the Knock Sensor tapped hole for mounting. Only on the front one. This was under the very dry looking threads of the knock sensor???? Indicating the oil was in the hole before the sensor was installed. Which woudl be inpossible as a factory assembly would be dry. My records start at 4,400 miles and I have no record of such a repair.
The oil soaked sensor was NOT reused. I forked over $50 for new one and new connector $15. The grommets that failed were only $3.44 each.
I worked hard to clean and perform a good install. I used a new Valley Cover gasket to be sure no additional oil leaks woudl be introduces. The Coolant by-pass lines were awkward but went together well. Routing of the Knock Sensor harness was not according to the manual and required rerouting and taping to hold in place. The upper rubber seals are hardened as well and do not provide a tight seal. But they were only available with the complete harness so I used the old ones. I intend to do more engine work in the next year anyway.
The intake is also a pain as you must install the two rear bolts before locating the manifold, then they can hang up on the intake ports. Cables need to be cared for and it all did hook up pretty easily. I had to reconnect the vacuum sensor and aux vac line at the rear of the mainfold, almost forgot them too.
Reconnect the battery and triple check everything.
Said a short pray. The LS1 fired up immediately.
Drove for 30 minutes NO CODES!!!!!!!!!!!!!
Will go longer today and capture an EASE trace to check, timimg, fuel trims and knock.
I must say it felts SO good to fix it myself. The experience illustrates the value of detailed diagnosis and care in assembly and also the value of GM parts even after warrenty. The parts guys were most helpful.
Thanks I will report if anything else shows up.

 

[TODD L GRIFFITH]

NICE JOB!

nice job, but a pain to get at those knock sensors. I replaced one about 3 months ago, right after I installed the Z06 intake. Had to take it all off again, but in half the time of the first time.