Tech 101: LS Oil Pressure Tap

By Jeff Smith

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April 26, 2026A simple way to access oil pressure for a mechanical or electrical oil pressure gauge on GM’s LS engines is to use the oil filter bypass cover. These factory covers came on the Gen III/IV engines but are not easy to find individually. We shopped around and found a reasonably priced cover for under $15 from ProTouringstore.com listed as an oil bypass cover. You can also find this cover on the internet under GM part number 12577903.

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With the cover removed, you can easily drill and tap a ¼-inch NPT hole for a simple oil pressure adapter tap to feed oil pressure to your mechanical or electrical oil pressure gauge. Of course, there are also numerous billet aluminum versions of this tap that come with the 1/8-inch NPT threads already in place. If you’re willing and able to drill a hole and cut threads, this simple cover will do the job for half the money.