i have a 92 k15 blazer with a 5.7 liter tbi and today was the first day that it got rather cold. I noticed my oil pressure was reading rather low maybe 15 psi i am running 5w-30 Mobil 1 5000 i also noticed that today i am leaking oil from somewhere and i am basically stumped seeing as the last time i changed my oil was a month ago and it hasn't leaked until tonight any help would me much appreciated thanks in advance I was thinking that maybe i need to change to a different weight oil maybe 10w-30 for winter the truck starts fine and runs well with no knocks

 

leaking oil from where?......................the intake? the heads? pan? rear main? try cleaning the engine (if it's covered in sludge) and maybe it'll show up easier. the 15 psi reading, was it @ cold or running temp? what's the mileage on your engine? maybe the pump is wearing out, & the pressure is bleeding back past the rotor instead of going through the motor. as for changing to the 10w-30, & without knowing where u live, i'd say no. the '10' is going 2 b thicker at lower temps than the 5w-30, and harder to flow (longer metal 2 metal contact b4 lubrication is flowing).

 

From the best i could tell it was leaking from around the oil pump but it could also be from around the pan
i checked all to see if the oil filter was tight as well as the drain plug and they are fine i do need to get under the truck and clean out the grease so i can tell for sure im hoping it is just bad seal because 10 minutes before i noticed the low oil pressure i was getting accurate reading im going to wait overnight and see if the problem is still there it was at running temperature i had just been driving for around 30 minutes

 

First , what is the oil level on the dipstick ??

Second , were you always using 5W30 prior to this ??

Third , check to see if the oil is dripping down the side of the filter. You say it's tight though it may not be tight enough.

If you were using 10W30 before then switched to 5W30 you will notice more leaking because of the lower viscosity. It may have been minor leaks with the 10W30 and not as noticeable, when you put in the 5W30 those same points leaking will show a lot more especially when the temp. rises.

Btw... being from the great white frigid north ... I use 5W30 for winter in my '86 pickup with a 5.0 liter. The rear seal leaks on my truck so until it gets more cold it leaks more with 5W30 than the higher viscosity 10W30. If your temp. range is between 0 degree F and above use 10W30 if below 0 degree F and lower use 5w30 , in accordance with GM.

 

Another possibility is the sensor is going bad. Might check pressure with external pressure gauge.

Not sure what you meant by "it was leaking from around the oil pump but it could also be from around the pan" since the oil pump is inside the pan.