1999 Chevy k1500 5.7 Vortec oil pressure

[Wheezy Salmon]

Hey, when i accelerate from a dead stop or do a burnout, my oil pressure gauge drops to zero then comes back up. engine sounds fine when the gauge reads zero. And also my oil pressure is reading lower than usual. at idle is reads normal. cruising at 50 mph it reads about 30-38 psi when usually at that speed itd be a little above 40. I think the low oil pressure is caused by me putting about half a quart of 5w-20 when it already had 5w-30 in it. i added oil out of a panic when my oil gauge started doing that

 

[Abuentipo]

Hey, when i accelerate from a dead stop or do a burnout, my oil pressure gauge drops to zero then comes back up. engine sounds fine when the gauge reads zero. And also my oil pressure is reading lower than usual. at idle is reads normal. cruising at 50 mph it reads about 30-38 psi when usually at that speed itd be a little above 40. I think the low oil pressure is caused by me putting about half a quart of 5w-20 when it already had 5w-30 in it. i added oil out of a panic when my oil gauge started doing that

 

[Stokes1114]

Check your oil pressure sending unit. They go bad often or even start to get a little plugged up. You can check actual pressure with a mechanical gauge hooked up there. Just be careful the fitting it's plugged into is somewhat fragile. Use 2 wrenches on it and the sensor. At the back of the engine on top, to the right of dizzy.

 

[Abuentipo]

My oil pressure does the same type of thing. When I start my engine it jumps up to almost 80 I have to let it warm up to halfway in order for it to be able to go to a normal temperature. When I know it's the oil pump. But all these from 96 to 99 do the same type of thing as what's happening to you

 

[Supercharged111]

It really sounds more like an indication issue than a real pressure issue.

 

[Wheezy Salmon]

Yea i hopped it was a sensor screwed up. this is the second motor the trucks had and it has 200k on it. if this one blows im gonna buy a brand new long block. ill have to hook up a mechanical gauge and see. hopefully its just the sending unit

 

[Wheezy Salmon]

I think the low pressure issue is cause i mixeds 5w20 with 5w30.

 

[Abuentipo]

When was the last oil change?

 

[Wheezy Salmon]

My buddy i bought it from said it was changed right before i bought it. so about 3k miles ago. i planned on changing it this weekend

 

[Wheezy Salmon]

What do you mean by the fitting is fragile?