99 silverado 5.3 oil pressure

[vandenbroekjj]

First of thank you to everyone for all the info on here.

 

Alright lm7 with 336k on it one owner. About start up zero oil pressure and associated tick of low oil pressure. Give the truck a little gas and the oil pressure jumps to around 15 psi I have to hold it there until the truck gets warm. After the truck is warm it will idle on its own with around 20 psi. When driving the truck sits around 35 to 40 psi.

 

Changed sending unit and cleaned underneath it.

Used manual gauge to verify correct pressure.

 

Leaning towards the o ring being worn on pick up tube. But I'm going to change the pump as well melling m295hv is what I was looking at is the high volume worth it?

 

Just wanted to see if you guys think I'm going in the right direction with my troubleshooting thank you in advance for your help.

 

 

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[Supreme Pizza]

High volume pumps can cause problems if you spend too much time at higher PRMs. They can actually starve the bottom end of oil. Under the right conditions and PRM range, you put all of the oil into the top end faster than it can flow back down to the crank. 

[vandenbroekjj]

High volume pumps can cause problems if you spend too much time at higher PRMs. They can actually starve the bottom end of oil. Under the right conditions and PRM range, you put all of the oil into the top end faster than it can flow back down to the crank. 

Good to know I just use it to tow my boat and run to the hardware store just was unsure if it would be a good idea to use it on a high mileage engine over the stock one


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[Supreme Pizza]

You might get better oil pressure results by changing the oil brand and weight, as well as the oil filter type. 

[vandenbroekjj]

You might get better oil pressure results by changing the oil brand and weight, as well as the oil filter type. 

Been using Fram the life of the truck every 3000miles 10w30 winter and 10w40 summer. It's just weird because after the truck is warm it idles at 20 and 40ish when driving. Part of me wants to try to fix it and the other part of me just wants to leave it until it actually stops working


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[Supreme Pizza]

 

 

 

If it was mine, I would try different oil/filter, then if that didn't work, I would replace the oil pump. 

 

 

 

 

 

 

[Tahoenate]

My 5.3 had similar problems including a knock and no oil pressure. Once oil pressure finally rose to about 20 the motor ran quiet. After a complete tear down i had several mushroomed lifters worn cam and main bearings..nothing spun because i tore it down in time...the magical o ring trick doesnt apply here. It was in great shape lol

[Tahoenate]

Rod bearings as well

[Supreme Pizza]

Complete tear down? Not worth the trouble. You can buy an OEM junk yard motor for around $80 from the local junk yard, with a 90 day warranty. Run it till it explodes, then pay someone $100 to install the junk yard motor for ya. If the junk yard motor is solid, throw a $100 tune up into it. 

[Tahoenate]

A good lm7 is 700 now days..and who in the world does a motor swap for a 100 lol. Not me

[Supreme Pizza]

The people that do motor swaps for $100 are butt plugs. Never the less, there are plenty of butt pugs out there looking for $100 bills. 

[vandenbroekjj]

My 5.3 had similar problems including a knock and no oil pressure. Once oil pressure finally rose to about 20 the motor ran quiet. After a complete tear down i had several mushroomed lifters worn cam and main bearings..nothing spun because i tore it down in time...the magical o ring trick doesnt apply here. It was in great shape lol

Yeah mine runs at 40 down the highway. And higher if I get on it. I'm really on the fence aout the high volume oil pump or just driving the truck until it gets worse. At this point I only have a knock and 0 psi for about 20 seconds if I stay in there and warm it up with about 1500 rpms


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[Tahoenate]

Yeah mine runs at 40 down the highway. And higher if I get on it. I'm really on the fence aout the high volume oil pump or just driving the truck until it gets worse. At this point I only have a knock and 0 psi for about 20 seconds if I stay in there and warm it up with about 1500 rpms


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Thats about how mine acted..but in the winter it really took awhile to get pressure so i tore it down..

[Supreme Pizza]

 

It it has oil pressure and doesn't make noise when its warm, then just make it warm: 

 

 

 

https://www.amazon.com/Zerostart-310-0054-Engine-Block-Heater/dp/B000NM73YG/ref=sr_1_4?s=automotive&ie=UTF8&qid=1525782141&vehicle=2001-47-491-20---6--1306------66-0&sr=1-4&ymm=2001%3Achevrolet%3Asilverado+1500

 

https://www.amazon.com/Kats-13100-Aluminum-Circulating-Heater/dp/B000BO8X9K/ref=sr_1_1?s=automotive&ie=UTF8&qid=1525782141&vehicle=2001-47-491-20---6--1306------66-0&sr=1-1&ymm=2001%3Achevrolet%3Asilverado+1500

 

https://www.amazon.com/Kats-24100-Watt-Universal-Heater/dp/B000I8VL3O/ref=sr_1_7?ie=UTF8&qid=1525782245&sr=8-7&keywords=oil+heater+pad

[Tahoenate]

 
It it has oil pressure and doesn't make noise when its warm, then just make it warm: 
 
 
 
https://www.amazon.com/Zerostart-310-0054-Engine-Block-Heater/dp/B000NM73YG/ref=sr_1_4?s=automotive&ie=UTF8&qid=1525782141&vehicle=2001-47-491-20---6--1306------66-0&sr=1-4&ymm=2001%3Achevrolet%3Asilverado+1500
 
https://www.amazon.com/Kats-13100-Aluminum-Circulating-Heater/dp/B000BO8X9K/ref=sr_1_1?s=automotive&ie=UTF8&qid=1525782141&vehicle=2001-47-491-20---6--1306------66-0&sr=1-1&ymm=2001%3Achevrolet%3Asilverado+1500
 
https://www.amazon.com/Kats-24100-Watt-Universal-Heater/dp/B000I8VL3O/ref=sr_1_7?ie=UTF8&qid=1525782245&sr=8-7&keywords=oil+heater+pad

Yeah thats bound to fix the under lying worn bearing issue