low oil pressure 5.7 engine

[gonzo694]

I have a 5.7 engine in my silverado! when starting it up the pressuere is around 45 after it heats up and come to a stop it drops around 20///i have heard that it may be a faulty guage! It burns no oil and doesnt knock ....it runs strong and i never beat on it can someone help me out ?thanks guys and keep up the good work

[jumpingjack66]

how many miles what oil and viscosity

[gonzo694]

Originally Posted by jumpingjack66

how many miles what oil and viscosity

hi jumpingjack..it has just over 54,000 and ive been useing 10w30 synthethic blend......i was told that i should run a 15w 40 and thats whats recommended for the engine by the manufacturer...does this make sence to you????

[Thunderbolt]

Originally Posted by gonzo694

hi jumpingjack..it has just over 54,000 and ive been useing 10w30 synthethic blend......i was told that i should run a 15w 40 and thats whats recommended for the engine by the manufacturer...does this make sence to you????

General motors does not reccomend 15w-40 in any gas engine, They don't even reccomend 10w-40. What they do reccomend is 5w30 or if it is above zero outside 10w-30. When you say the oil pressure droppes to 20psi when it stops do you mean at idle ?? If it is at idle it is normal. What is the oil pressure at 2,000 rpm ??? The spec calls for not less than 18psi at 2,000 rpm, But that would be low. My guess is if the 20 is at idle you should have between 35 and 45 at 2,000 rpm when hot. You can use 15w40 and it won't hurt anything and it will raise the pressure some, But it is no solution to low oil pressure. My 98 has 190,000 miles on it and ny oil pressure with 5w30 amsoil is at 20 psi at hot idle and 35-45 psi at 2,000 rpm. If I use regular 5w-30 dino oil it is just under 40 psi at 2,000 rpm which is within spec, But shows some wear. I have other issues such as a bad wrist pin and every once in awhile on a cold start a slight knock for a second, But it has been doing that for 40,000 miles and is just now reaching a point where I set the money aside for a new long block. I am still going to run it until it needs to be replaced, But the time is coming.

[gonzo694]

Originally Posted by Thunderbolt

General motors does not reccomend 15w-40 in any gas engine, They don't even reccomend 10w-40. What they do reccomend is 5w30 or if it is above zero outside 10w-30. When you say the oil pressure droppes to 20psi when it stops do you mean at idle ?? If it is at idle it is normal. What is the oil pressure at 2,000 rpm ??? The spec calls for not less than 18psi at 2,000 rpm, But that would be low. My guess is if the 20 is at idle you should have between 35 and 45 at 2,000 rpm when hot. You can use 15w40 and it won't hurt anything and it will raise the pressure some, But it is no solution to low oil pressure. My 98 has 190,000 miles on it and ny oil pressure with 5w30 amsoil is at 20 psi at hot idle and 35-45 psi at 2,000 rpm. If I use regular 5w-30 dino oil it is just under 40 psi at 2,000 rpm which is within spec, But shows some wear. I have other issues such as a bad wrist pin and every once in awhile on a cold start a slight knock for a second, But it has been doing that for 40,000 miles and is just now reaching a point where I set the money aside for a new long block. I am still going to run it until it needs to be replaced, But the time is coming.

HI THUNDERBOLT.....WHEN I WAS SPEAKING OF 20PSI ..YES THATS AT IDLE WHEN AT A STOP LIGHT ..BUT WHEN ACCELERATING IT DOES RISE TO 40-42 PSI......I REALLY NEVER NOTICED IT BEFORE ,,BUT SINCE I HAD A TRANSMISSION LINE REPLACED AND BLOW OFF THE HOURS AFTER IT WAS REPLACED I STARTED TO WATCH MY GUAGES...DUE TO THE MECHANIC I TOOK IT TO DIDNT FLARE OUT THE LINE OR DBL CLAMP IT AND IT BLEW OFF AND COATED MY ENTIRE ENGINE WITH TRANSMISSION OIL AND HE ALSO REPLACED WATER PUMP,TUNE UP AND A FEW OTHER THINGS SO AS U CAN SEE THIS IS WHY I WATCH MY GUAGES ....ESPECIALLY THE TEMP SINCE HE REPLACE A THERMOSTAT I APRRECIATE THE FEEDBACK THANK YOU ...JUST WANTED TO MAKE SURE MY ENGINE WAS SAFE .....OH BY THE WAY HE DETAILED THE ENGINE NICELY AND I HAVE IT LISTED WITH PICTURES AT CARDOMAIN.COM UNDER DAVE'S SILVERADO 95........THANKS AGAIN