Mystery Oil Leak

[Jason in DLH]

On the oil cooler line block, there is a plug on its side. Using a 3/8 Allen wrench remove the plug, replace that plug's O-ring, you are good to go.


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I got to thinking more about this random plug GM put on the side....why is it there? What is it supposed to do? Besides provide a spot to leak that is.

 

[kbuskill]

I got to thinking more about this random plug GM put on the side....why is it there? What is it supposed to do? Besides provide a spot to leak that is.

Good spot to install a oil temperature sensor or mechanical pressure sensor.

 

[Geotrash]

Good spot to install a oil temperature sensor or mechanical pressure sensor.

Yes.

And it's there because the engine block itself is used in vehicles both with and without external oil coolers. Blocking the ports with a plate is more economical than having different block castings for each application.

 

[Jason in DLH]

That makes complete sense now. Thanks!

 

[JonnyTahoe]

On the oil cooler line block, there is a plug on its side. Using a 3/8 Allen wrench remove the plug, replace that plug's O-ring, you are good to go.


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First time I have seen the cooler block my trucks don't have coolers.

 

[Jason in DLH]

What trucks do you have?

 

[14RamHemiSport]

I attempted this last weekend along with an oil change. Found out (and looking back I'm not sure how I missed it as it looks quite different) I have the cooler lines running in here, not just the block off plate. I was able to access this with a small ratchet and finagling my arm up in there on my back. I have an 09 denali awd. Prior too, I was convinced I had the block off plate, I ordered the gasket and plate itself. Glad they are cheap. So I wiped off the gasket (it looked ok) reinstalled and tightened down. I need to go back under and see if it dried up any. Not seeing any drops on the garage floor.

 

[JTRATX]

Anyone know the size of the O ring on the side of the block off plate?

On the oil cooler line block, there is a plug on its side. Using a 3/8 Allen wrench remove the plug, replace that plug's O-ring, you are good to go.


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[jz57]

As a substitute, you could use white plumbing tape wrapping around the plug thread.

Anyone know the size of the O ring on the side of the block off plate?

 

[GMCSwurvn]

Rear main?