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Oil Filter Pressure Relief Valve Plugged?

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So the last time I changed my oil in my L28ET (F54 block) I managed to mess up the threads on the oil filter bung. I called Motorsport Auto to order a new one, and the gentleman I talked to recommended I also get a new pressure relief valve. It was only $6 so I did, even though I didn't recall their being one on my engine, and I had actually never heard of this part before. 

Now when I was changing my oil this afternoon, I was going to install the new pressure relief valve, and discovered that my block actually has what appears to be a metal plug installed where the valve should be. I checked my old L24 block, and it has the valve, not a plug. 

I have been driving the car with this engine for some time and never had any issues related to oil pressure.

My question I guess is, is this something that a previous owner did out of negligence/laziness or is the valve not really needed? I have searched and haven't really found much info on the topic one way or the other. I am hoping it is not a big deal as the only way I can see me getting that plug out would be to drop the oil pan and somehow try to push it out, or drill and tap it from the outside. Both options sound painful right now. I went ahead and reinstalled the oil filter for now, as this has not given me any issues so far. I just want to know if I should add fixing this to my to-do list or if it is not worth bothering over. 

I attached a picture of my plug below, and here is a link to the part that should be there: http://www.thezstore.com/page/TZS/PROD/17-8041

Let me know your thoughts.


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Many oil filters have a bypass built in. Not all, so determining whether yours does or not falls to you.

The factory L28et oil cooler has a bypass built in. I believe the block bypass is plugged in these applications, but I'm not absolutely sure. Perhaps this is what you have?

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You can find an oil filter that has a bypass, or your local auto parts store clerk can help you with that.

You can run without a bypass, but a filter failure will likely cause further problems that the bypass protects against.

I don't have an L28et to inspect, but I can confirm the L28et factory cooler has a bypass built in that allows oil to bypass the filter but not the oil heat exchanger. I can confirm that the RB25 from the factory has an extra oil passage as shown on your L series picture. The RB25det passage is also blocked because the bypass valves are in the cooler assembly and the RB25de passage is not blocked and contains a bypass because it doesn't come with a factory cooler.


Edited by jthom5147
Edit: PM me if you're in need of a factory cooler.

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