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Somebody explain how this is healthy for an engine

Jgarner

By Jgarner
in Troubleshooting & Recalls

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Jgarner Enthusiast

Jgarner

Posted
Posted

I understand they say the oil pressure drops at idle but come on now this is a little much. I feel like I can't take my eye off the gauge like I'm waiting for it to drop to 0. This is driving me insane it's worse when the weather is warm and it hasn't even hit the dead of summer yet. Any tip on a safe way to get some more pressure out of it would be great or if it's normal and it's the same on other trucks. As soon as I drive the pressure rebounds to just below 40psi.post-167394-0-88871600-1490132508_thumb.jpg

post-167394-0-88871600-1490132508_thumb.jpg

post-167394-0-88871600-1490132508_thumb.jpg

post-167394-0-88871600-1490132508_thumb.jpg

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DaveH71 Enthusiast

DaveH71

Posted
Posted

Your truck has a two stage oil pump. At idle it enters low stage and drops the oil pressure to around 20 psi to increase engine efficiency. Pump working less = higher efficiency for the engine.

 

Once you start to accelerate the pump returns to high operation mode and increases oil pressure based on RPM and load.

 

6 psi is minimum spec for every 1000rpm for gm. Your truck is fine.

TJay74 Senior Enthusiast

TJay74

Posted
Posted

I would be more worried about running your fuel tank that low than the oil pressure being that low. Hard on fuel pumps as they can tend to run hot when the fuel tank is run low.

trik396 Enthusiast

trik396

Posted
Posted

Your truck has a two stage oil pump. At idle it enters low stage and drops the oil pressure to around 20 psi to increase engine efficiency. Pump working less = higher efficiency for the engine.

 

Once you start to accelerate the pump returns to high operation mode and increases oil pressure based on RPM and load.

 

6 psi is minimum spec for every 1000rpm for gm. Your truck is fine.

I've always heard 10 psi per 1000rpms but either way he is fine
Pacfanweb Enthusiast

Pacfanweb

Posted
Posted

That's plenty of pressure, especially with today's oil.

 

I'd be more concerned about being out of gas. Never run it that low.

Pacfanweb Enthusiast

Pacfanweb

Posted
Posted

 

 

Why? He has plenty of miles left where his gas gage is in that picture.

 

Because it's low, and that uncovers the fuel pump when driving, and THAT leads to shortened fuel pump life.

 

The fuel level isn't about how many miles you have left. You should always consider 1/4 tank "fill up time".

ChevyMan2015 Enthusiast

ChevyMan2015

Posted
Posted

 

Because it's low, and that uncovers the fuel pump when driving, and THAT leads to shortened fuel pump life.

 

The fuel level isn't about how many miles you have left. You should always consider 1/4 tank "fill up time".

 

 

I must have missed this in the owner's manual. Can you tell me what page says to never let the fuel gauge to get below 1/4 tank or it will shorten the life of the fuel pump? Weird, I had no idea.

diyer2 Senior Enthusiast

diyer2

Posted
Posted

 

Because it's low, and that uncovers the fuel pump when driving, and THAT leads to shortened fuel pump life.

 

The fuel level isn't about how many miles you have left. You should always consider 1/4 tank "fill up time".

 

FACT NOT BS I do a half tank then fill. Why wait, your gonna buy it.

 

Oil pressure, volume, gallons per minute is the key IMO. :happysad:

KARNUT Senior Enthusiast

KARNUT

Posted
Posted

I rarely go under 1/2 of tank, sometimes cruising down the HWY a quarter of tank. It's been known for awhile its better for the fuel pump to go 1/2 or better.

Pacfanweb Enthusiast

Pacfanweb

Posted
Posted

 

 

I must have missed this in the owner's manual. Can you tell me what page says to never let the fuel gauge to get below 1/4 tank or it will shorten the life of the fuel pump? Weird, I had no idea.

Does the owner's manual tell you when the change the brakes? Does it tell you when to wash the truck? Does it tell you when your tires are going to wear out? Does it tell you when your transmission is going to fail?

 

It's common knowledge. Run anything with an in-tank pump low a lot and it shortens the life. GM's are known for going through fuel pumps. This is one way to extend the life of them.

ChevyMan2015 Enthusiast

ChevyMan2015

Posted
Posted

Does the owner's manual tell you when the change the brakes? Does it tell you when to wash the truck? Does it tell you when your tires are going to wear out? Does it tell you when your transmission is going to fail?

 

It's common knowledge. Run anything with an in-tank pump low a lot and it shortens the life. GM's are known for going through fuel pumps. This is one way to extend the life of them.

 

Those things are common knowledge, yes, but I would argue that the fuel pump "issue" is not. I have owned a GMC or Chevrolet truck since 1998. I always get gas when the gas light comes on, and I have NEVER had a fuel pump issue. So, no, it is not common knowledge for me. That is why I asked about it in the first place.

trik396 Enthusiast

trik396

Posted
Posted

I think this was probably true years ago but the way fuel is returned to the sump and architecture of current fuel systems probably makes this issue moot. Not saying it's a bad idea to keep your pump immersed in fuel but I wouldn't lose sleep over it

pm26 Senior Enthusiast

pm26

Posted
Posted

Think of fuel in the tank as electric pump motor coolant - the pump motor is actually cooled by the gasoline in the tank. As your fuel level drops so that the pump motor is partially exposed, the cooling efficiency decreases. Remember the pump runs all the time while the engine is running. So keeping that little motor cool is a good idea.

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