ATTENTION anyone with oil pressure issues

[newdude]

4 minutes ago, KevinRC said:

2005 Silverado WT 4.8. Recently purchased and restoring.

 

209K, I am at 40 PSI after additive and changing the oil with high mileage conventional oil. It was  lower.

 

Appreciate the information, but just another "thing" i should look at.

 

40 PSI is in the middle of the gauge and what I was taught, middle is good.

 

I have read about 60 PSI?

 

Would anyone know what the correct oil pressure should be ?

 

TIA

KC

 

 

Minimum oil pressure specs are as follow:

 

6 psi at 1,000 engine RPM

18 psi at 2,000 engine RPM

24 psi at 4,000 engine RPM

[Grubbworm]

I had a slight issue with my oil pressure being lower than 40 PSI. I ended up using a White K&N Oil Filter and Castrol GTX Full Synthetic High Mileage oil. So far it has been above 40 PSI.

[ElectricBill]

On 2/27/2015 at 11:01 AM, 00Silverado4x4 said:

The older 99-07 were the same way...something I'm probably looking at having to do eventually...no fun.

Yes, other vehicle manufacturers also use these screens. My Dodge Dakota 4.7 liter V-8 uses one of these screens. I also never heard of such a thing. I have a similar problem. When I first start it, the oil pressure is fine, then the gauge drops to zero after about 30 seconds. I haven't gotten around to fixing it yet. I have a new sending unit. The auto parts store was out of stock on the screens. I figured I would clean it in a jar of gasoline. I seen this post while finding information on oil pressure port access plugs located on the 8.1 liter Chevrolet engine in my dually truck. I am pretty sure this engine uses a screen also. To remove them, take out the sending unit or switch unit. Then inside the threaded hole in the engine block you'll need a dental pick tool to hook it out. It's pretty crazy that they have that shoved in there. Especially being my Dodge looks to have a typical 1/8" NPT threaded hole. That's pretty small to put a screen into but they do it.

One other thing that I learned from my friend that is a mechanic for a Ford dealership. He said a lot of oil pressure gages in vehicles are actually not gages. As soon as the pressure "switch" gets as much as 4 psi or higher, the contact closes and sends voltage to the "gauge". This gauge is nothing more than a electromagnetic device that always reads mid deflection in the normal range. Does not matter if there's 4 psi or 80 psi. This is basically an analog idiot light/guage. This is why you'll see the sending unit called an oil switch or oil sensor switch.  A regular sending unit is a variable resistance device that changes in resistance value depending upon the pressure. This has a variable/changing current going through a real gauge/meter. This gives you true PSI readings on the dash and you'll see the reading change from an idle to higher RPM. The switch type sending unit will move a tiny bit when you rev the engine, this is because the alternator is putting out more power. It's a very slight movement that's barely noticeable. I think Ford Rangers use this switch type sending unit to the fake dash gauge. People want gauges in their cars/trucks instead of idiot lights right? Well Ford and others did give you gages! Nobody said they needed to be real!!!. LOL    

On 2/19/2015 at 7:02 PM, curtmerci said:

For those of you that have noticed oil pressure drops, etc. There IS a screen below the oil pressure sending unit that does become clogged!! I have an 07 GMC Sierra, 4x4 Crew Cab, SLE2 package, 144,000 miles. 5.3 litre. I change my oil faithfully at 3000 mile intervals, use Castrol GTX High Mileage oil and Purolator oil filters. Air filter gets replaced every other oil change. Now for what happened...... very cold day, pulled out onto the Interstate and accelerated only to hear the truck rev, and go nowhere. Dropped it out of overdrive and got going, then lost that gear. Limped it to a shop in 2nd....yes the tranny went out. Had a new tranny installed and the mechanics called me and said when they test drove the truck, it had lost oil pressure and shut down. They replaced the oil pressure switch, and it had 40 psi of pressure but slowly dropped down to nothing and shut off. By now the first thought was oil pump or pick up. I called a couple of shops to get answers, and no one ever mentioned (or had even heard of) a screen located just below the oil pressure switch. Called local GM dealer and did confirm that there indeed is a small screen below the switch. $5.80 filter screen. We pulled the old one out, put in the new screen, reinstalled the new pressure switch and all is good. Now some of you may know about this little screen/filter. But I did not, and neither did a few reputable shops. Basically I am posting this to inform others. That's what we're all here for. I'm not sure if this filter is installed on other engines, or even what model year. Maybe someone that knows can chime in. In this case it really paid to call a GM dealership with a good service department. I might have been pulling an engine over a $5.80 filter screen. As to why it plugged up, I'm not sure. We cut apart the oil filter, and no sludge or foreign material. Hopefully this post will help inform someone and save them some big bucks............Or maybe I live in an area where we are way behind on our info on GM vehicles....lol

On 2/19/2015 at 7:02 PM, curtmerci said:

For those of you that have noticed oil pressure drops, etc. There IS a screen below the oil pressure sending unit that does become clogged!! I have an 07 GMC Sierra, 4x4 Crew Cab, SLE2 package, 144,000 miles. 5.3 litre. I change my oil faithfully at 3000 mile intervals, use Castrol GTX High Mileage oil and Purolator oil filters. Air filter gets replaced every other oil change. Now for what happened...... very cold day, pulled out onto the Interstate and accelerated only to hear the truck rev, and go nowhere. Dropped it out of overdrive and got going, then lost that gear. Limped it to a shop in 2nd....yes the tranny went out. Had a new tranny installed and the mechanics called me and said when they test drove the truck, it had lost oil pressure and shut down. They replaced the oil pressure switch, and it had 40 psi of pressure but slowly dropped down to nothing and shut off. By now the first thought was oil pump or pick up. I called a couple of shops to get answers, and no one ever mentioned (or had even heard of) a screen located just below the oil pressure switch. Called local GM dealer and did confirm that there indeed is a small screen below the switch. $5.80 filter screen. We pulled the old one out, put in the new screen, reinstalled the new pressure switch and all is good. Now some of you may know about this little screen/filter. But I did not, and neither did a few reputable shops. Basically I am posting this to inform others. That's what we're all here for. I'm not sure if this filter is installed on other engines, or even what model year. Maybe someone that knows can chime in. In this case it really paid to call a GM dealership with a good service department. I might have been pulling an engine over a $5.80 filter screen. As to why it plugged up, I'm not sure. We cut apart the oil filter, and no sludge or foreign material. Hopefully this post will help inform someone and save them some big bucks............Or maybe I live in an area where we are way behind on our info on GM vehicles....lol

 

[DonM32170]

So, I have a 2008 Silverado 1500 LT, 5.3L V8. I got this truck about a year ago of a local used car dealership for, what I think, is a steal at $2000. Is had 205,000ish miles on it. The dealer threw it in with another purchase we were making because they couldn't figure out an oil pressure issue. I immediately assumed oil pressure switch, and bought it. At cold start, the pressure will fall to alarming levels and lugs out. While driving at any speed, the oil pressure is at correct operating pressure (40psi). It only drops sitting idle. Once I've driven it that it's at operating engine temp, it will hold pressure even at idle. 

I changed the oil pressure switch (and I think the screen too), still have oil pressure issue. I didn't drive it very much at all this first year, only cranked it up when tinkering with it. For the last 2 months it's been my daily driver. I can feather the throttle to juggle the oil pressure until I get moving. 

My current thinking is either the oil pickup tube, the O-ring at its bottom or pump. My question being: is there a more-common-than-not culprit or best to replace all of that? 

Sorry for the long post, I felt like the context is somewhat important. Thanks in advance

[Marcus2]

This is a really old post, but here I am in 2026 overhauling my 1999 GMC Sierra. I had an issue where when I started the truck, the oil pressure on the guage would not move for about 3-4 seconds, then it would start rising and stay there. I thought My sensor was clogged since I had done a couple of fuel treatments with Chevron Techrolene and when I dumped the oil and filter, it was totally black with all the carbon the techrolene had removed. SO, I started looking on Amazon for sensors, and discovered that they are suppossed to have a filter in the port. So I purchased a filter which Amazon swore it was for my truck. I got the old sensor out and discovered there was no filter on the port! I thought to myself, well, that's why the sensor got colgged. I attempted to install the filter, but it would not drop down any further than the top of the hole. There was no room to start the sensor into the port with the filter in there. So, I started to do some research with Chatbox, and discovered the early 5.3L sensors  had no filter. ALSO, you can tell if your 1999 (or later)?? model year does not require a filter because your existing sensor has only ONE wire. Later models, (those needing a filter) will have THREE wires. Also, The correct Sensor Is a D1818A / 19244505 for single wire sensors. Hope this saves some of you some time and keeps you from having to cuss out Amazon. Even tho they frequently need it. 

[davester]

The filter under the OPS is for engines with AFM, which didn't start for trucks until 07.5

 

I think around '02/'03, when GM rejigged the computers and wiring, they also moved to a multi-pin OPS, but still didn't have the filter under it.

Edited June 7 by davester