The Stovebolt Site Forums The Shop Area Engine Shop Slow to build oil pressure on gauge...

I've searched and found a few recent posts about what I'm observing.

I've recently installed a bypass oil filter.

When I start now, the gauge won't show pressure until about 4 seconds of running, less if I give it a shot of throttle.

Before the filter install, I observed a pressure reading right away.

I'm sure it's pretty safe to say that the bypass filter lets some oil back into the pan after I shut it off. Once it builds pressure, it runs just as it did before the filter was installed.

Is this acceptable, or should I have pressure from the get go, even with the bypass filter?

Mark

Hi, Mark, Brian here, I just read your post so I just went down to the carport and started my truck (only parked about 20 min.) and started it , slow idle,( 550 RPM) it took about 10 seconds for oil pressure to show. Note: I am trying out mercruiser 25/40 oil this year and it has about 700mi. on it. I can check it tomorrow on a cold start. My engine has about 130,000 miles on it and to my knowledge has not been rebuilt.

Thanks for that test Brian - appreciate that.

Do you have a bypass filter?

Hi,Mark, I think I have the bypass filter. The fitting is on the lower rear driver side of the block, comes out and tees to two oil lines. Small one to the oil pressure gauge, larger one to the oil filter on the manifold and then out of the filter and back to the block. On my cold start this morning the pressure showed up in about 3 sec. If I remember right, when I change the oil filter it takes about 20-30 sec. for pressure to show.

As You said some oil drains back after You shut it down and it may take a few sec. for the pump to fill the filter up.Mine takes about 5 sec. to come up and I have a filter.

Pete

FWIW

Mine, almost immediately

bypass yes, 54 car 235

temporary (almost 2 years now) sunpro oil gauge

piped like this
...pic...

builds pressure just cranking the starter.

I have to ask whats FWIW.

Pete

FWIW = for what its worth.....

FYI, JSUK, IIRC, FWIW, FWIW was not used when I was younger (oh, oh, P911 - not) - SOMY?

For Your Information
Just So You Know
If I Remember Correctly
For Whoever Is Wondering
For What It Is Worth

Should I be concerned? Before the filter it was instant... Im just wondering if parts are getting oil while the filter apparently tops up.

I don't experience much of a drain back from the canister, when I change oil and filter I have to get my handy suction pump tool the get the most of the oil out.

Someone else will have to answer if there is a concern.

Different models and brands of by-pass oil filters fill and empty at different heights.

Also, different oil gauge "sender" connections are at different places (which may or may not show delay in oil pressure going up). Is you oil pressure sender tube on the inflow or outflow side of the canister?

On the inflow.