Advice on knock sensors

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Blk00ss

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Our '05 Tahoe has an oil leak. Its been going on for quite a while. I was quite confident it was coming from top side, and have been monitoring it closely. I'm about 99% certain its the back side of the valley pan. So with that said, I'm going to be doing intake manifold gasket and valley pan gasket. We don't currently have any knock sensor issues, but while I have it apart, I figure I might as well change those as well as the seals. Looking online and at Rock auto, I see Dorman brand knock sensors. I've had good luck with Dorman brand items over the years, but are thse any good? And do I actually need a new harness as well? I suspect not. Just trying to finish up my list of parts I'll need so I can place my order. Not worried about oil sending unit as its newer, and not wet around the area. I'm also seeing this kit. Wasn't sure if its any good or not...

 

mattbta

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Sensors OEM only for me. Most do the harness at the same time, for good measure. However, OEM harness was unobtainium for me when I was doing them, so chinesium it was. I probably didn't need a new one, but I was in there and at the time it was the one/only time pulling the intake. Now i've done it 5-6 times...lol
 
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Blk00ss

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Sensors OEM only for me. Most do the harness at the same time, for good measure. However, OEM harness was unobtainium for me when I was doing them, so chinesium it was. I probably didn't need a new one, but I was in there and at the time it was the one/only time pulling the intake. Now i've done it 5-6 times...lol
Do you know if Delphi is OE? I didn't notice AC delco, but saw Delphi and I know Delphi is sometimes OE
 

Scottydoggs

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the leak is likely from the oil pressure sending unit. its mounted in the valley cover rear driver side.
 
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Blk00ss

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the leak is likely from the oil pressure sending unit. its mounted in the valley cover rear driver side.
Its not. As I stated, its not only new (I know where its located, I changed it), its completely dry all around it. I've cleaned back there and taken pics every few days to watch how the oil leaks. Its coming from a smidge up and forward before the pressure unit. Its also grimey on the front tside of the intake as well. Also, valley pan leaks are not uncommon on the 5.3
 
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Blk00ss

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Does anyone know if the coolant crossover pipe needs any attention while in there? Some peple replace the seals I guess. Can't you remove valley pan without messing with the pipe?
 

Sam Harris

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Sensors OEM only for me. Most do the harness at the same time, for good measure. However, OEM harness was unobtainium for me when I was doing them, so chinesium it was. I probably didn't need a new one, but I was in there and at the time it was the one/only time pulling the intake. Now i've done it 5-6 times...lol
Same. I replaced sensors and the harness with AC Delco. Though the harness was a bit tough to locate.
 

drno4

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Been there and done what you're doing ('03 Denali XL 6.0).

I would highly recommend OE only for the knock sensors and harnesses. I buy almost everything from Rock Auto but like you couldn't find them there when I did our job so I went to Amazon for those. Your parts may vary, but here are the sensor and harness P/Ns for my rig:

Genuine GM 12601822 Knock Sensor Wire
AC DELCO 213-3521 OEM Knock Sensor

Here also is a repair video I found helpful:

In the video, you'll see some old gasket maker on a portion of the perimeter of the knock sensor cavity. I would have scraped and cleaned that off had I been them, being careful not to get any old gasket flakes into the sensor cavity (plug it with a shop towel).

As I did on our rig, I used new red high temp gasket maker on roughly the same portion of the perimeter seen in the video (NOT the full circumference).

As for your gaskets, I only use/trust FelPro for all our family's vehicles and have never been disappointed.

Hope that's helpful. Blessings on your task, my friend!
 

Richyukon2001

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I would use OE for the knock sensors. MAKE SURE YOU FOLLOW THE TORQUE SPECS! I did not the first time had to the job 2x. I have had mixed results with Dorman. Also change the harness.
 

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