Oil pressure delay

[VIKING_MECHANIC]

On my 97' C1500, I'm starting to notice that there's a delay in when it gets oil pressure. Usually it's nearly instantaneous, but right now it take a second or two.

I don't think it's the oil pressure sensor because I can hear the difference when the engine starts.

Last time I changed the oil, there was no chunks of material in the oil, nor was it sparkly. So I don't believe the pickup screen is blocked by obstructions.

Is the oil pump about to fail? Does it show signs of failure? What else can cause this.

And I obviously want to fix this asap before it leads to catastrophic failure!

 

[thinger2]

Oil pump failure does happen but it is pretty rare.
I would change the oil with it hot and cut open the old oil filter.
It makes mess if you dont have a filter cutter so be prepared.
Dont use a hacksaw. That will put metal dust into the filter and screw up the reason for doing this.
I used to use a sacrificial wood chisel and hammer a big enough gap about a half inch past the base to get at it with tin snips and cut all the way around.
Once you cut the can off of the base, you can spread the paper pleats of the filter apart and look for glitter.
And dump the oil into a big pan before you cut it apart and let it sit so the metal settles out.
It wont tell you why you have an oil pressure problem.
But if that filter is full of glitter.
Then you have a mechanical issue.
Dont trust the factory oil pressure gauge.
They are worthless.
Attach a mechanical oil gauge to find out what you really have going on.
And look for oil leaks.
That noise at start could be valve noise, rod noise, etc..
But it could also be a cold misfire that has nothing to do with oil pressure but its enough to cause a little temporary problem with the ecu and that will make the gauge read bad.
I highly doubt that you have an oil pump failure.
Especially a cold start failure that cures itself in a few seconds.
Cut the filter open just to get some peace of mind.
Its a good to do anyway.

 

[Schurkey]

What kind of oil pressure gauge are you using?

Every winter, my old-fashioned mechanical gauges have slow response due to cold oil not flowing through the lil' plastic tube very well. Maybe the same thing with cold oil not flowing through the filter and engine-block passages as fast as when it was warmer out.

Or, a failing oil pressure sending unit.

But my guess is just plain ol' cold oil.

 

[Erik the Awful]

The oil pump is driven off the cam gear, and there's nothing that optional or timed about it. When the engine turns, it turns. If something were wrong, you wouldn't get a delay, you'd get low pressure or no pressure. Put a trusted gauge on it. If you have pressure, or even low pressure, I'd still run it. If you have no pressure, it's time for a rebuild.

I use a pipe cutter when I want to open an oil filter.
www.amazon.com/GEARWRENCH-2031DD-Exhaust-Tailpipe-Cutter/dp/B000M93OUM/

 

[Pinger]

The temperature doesn't have to drop much for oil to thicken. That makes it slower to get to the gauge sender to register as pressure.
If your oil is due a change it could be thickened due to oxidation which won't be helping. Probably just the cold though. Does the pressure come up straight away on a hot re-start?

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