well it seems to only do it when i drive it after a certain amount of time. When its first started it doesnt lose preesure at all. And wouldnt then engine run and smoke a hell of a lot if i had low oil pressure? It runs like a top

 

Check your Oil pressure with a manual gauge .,Mine didn't make any funny noises, Dealer checked mine with manual gauge it was low on gauge.. They install a new engine in my monte because it spun a cam shaft bearing in the block...

 

^ ^^ THIS ^^^

It is the only way to know for sure what your oil pressure is. Hook a gauge up and observe/compare its readings to that of your dash gauge. Better yet, if you can have a shop hook up a remote mechanical gauge and take the car for a spin. That way you can see if it is really dipping below safe pressure while idling at lights, etc. Hopefully it is just the sensor or something else simple, but I'd be getting that pressure checked asap!

 

My gauge on the dash dropped down three times no engine noise..,16,900 miles , I took it to dealer they hooked up maunal gauge it read close to zero at idle .. They removed engine an found spun cam shaft bearing in block. They installed new engine cost me $0.. My engine made no noise..

 

Low oil pressure does not equal smoking and noticeable performance problems. It can create small problems that become big ones (such as driving fine, then suddenly the engine seizes out of no where for example).

ZJerry made a good suggestion much earlier (and repeated it) to use a mechanical gauge to check it out. I opted for try replacing the sending unit (as it should be about a $10 part and I've known them to fail past 100,000 miles).

Bottom line, get this issue isolated before it becomes a seized motor or a spun bearing.

 

When the oil is cold it is thicker, you wouldnt notice any low pressure. As you drive, the oil heats up and it thins out.

 

Ummm...actually it's the exact opposite. The oil is thin when cold so it can flow quickly and offer some protection during startup. As it heats up viscosity increases.
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Have you had an external gauge hooked up yet to verify the readings of the gauge in the dash?

If it only does it once the engine is warm (and the oil is fresh) you may have worn bearings. When the engine is cold the clearance is tight (as it should be) and the pressure is acceptable. Once the engine warms the bearings expand and the clearance increases. As a result the pressure drops off. The same scenario is possible if the oil pump is worn.

You really need to get that external gauge hooked up so you can see what's going on...

 

wah...
I think MossyOakSilverado is right...Its thin when hot, thick when cool. Basic science, when hot it expands, when cool it contracts. If it was the opposite Oil would last forever. Heat thins it out, and breaks down the viscosity.

I've even seen the difference up close. Pouring waste oil in a container, one jug fresh from the engine & one that has been sitting in the bitter cold, same weights. The cold flowed slower than the hot oil.

That is why oil pressure runs higher at the first startup, takes longer for it to flow through.

Also, figured I'd put this here.
My first car died from a failing oil pump. (yah, killed a bulletproof 3800...at about 200k miles) The car had perfect pressure at the first cold start-up, but once it got to temperature the pressure began to drop significantly, basically into the red zone! I'd avoid driving at all costs, check your pressure & see whats up.

 

I logged on a little while ago and saw the above post made by 'me'. The first thing I thought was is going on? I got pissed and was going to immediately respond, but instead I changed my password and logged off and cool down a bit. At 8:37 this morning (the time the post was made) I was sitting in the parking lot of a grocery store talking on my HT while the wife was shopping. I don't access this forum from a smart phone - only a few different desktops. So I'm finding myself completely astounded that I was able to be in 2 places at once.

Yes MossyOak & Red, the viscosity of oil is lower when it is cold then when hot. I don't have a clue why 'I' would have stated differently. I stated my opinion long ago when I agreed with zjerry about using an external gauge to check the pressure.

Anyways, Put a fork in me...I'm done.

 

wow I cant believe you are on a car forum offering advice like this. Why do you think so much research is put into oil to help it perform better when its HOT? Cold oil is thicker than hot, as the oil heats up it thins out and breaks down, ie thermal breakdown. You want oil to maintain viscosity when its hot to help keep that protection between your metal to metal moving surfaces.