2006 2500H 6.0L Oil pressure

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by loaded94, Mar 15, 2017.

  1. loaded94

    loaded94 Rockstar

    When it is cold like below freezing my truck will sound alarm for low oil pressure when I start it up, and it seems like as I get out on the highway, and RPM rises it sounds again. Oil Pressure Gauge is showing just below 20 upon start, until I drive a few miles, and alarm sounds when I get over 45mph or so, until driven a few more miles. Eventually after I get moving 60 or so, it moves up to 40 or just below. I was running 5-30 Valvoline Max Life but changed to 10-30 max life on my three Brother in Law's recommendations. It did this before changing the oil weight, I also added a bottle of STP engine honey. Should I start thinking about a oil pump change? OR, should I purchase the oil sending unit, (or sensor?), Truck has 273,000 miles on her runs great no engine noises, but low oil pressure kinda scares me. Especially when I will be towing our 31ft fifth wheel camper.
     
  2. RayVoy

    RayVoy Rockstar 4 Years 5000 Posts

    It could be the sensor, that would be my first change.
     
  3. j cat

    j cat Epic Member 5+ Years 1000 Posts

    the oil pump O ring maybe the cause since the pressure rises after it warms up. that is the way it is reported with the O ring.. O ring leaks a little as time passes leaks more . this then prevents the pump from sucking up the oil through the sump screen.

    if it was always low then could be many other items at this age/miles. you don't want to thicken the oil . harder to suck up the oil ..
     
    silverado002 likes this.
  4. loaded94

    loaded94 Rockstar

    Well, running 5w-30 the damn valves make lots of noise on really hot days, running 10W-30 really makes the valves/rockers quit down nicely. Noticed that on all chevy engines that call for 5W30. Really quits down on engine noise, beside a little heavier oil should raise oil pressure, and really from 5W-10W isn't much, except 5W is like pouring water...............have an 97 lumina and running 5-30 the lifter noise is awful.
     
  5. j cat

    j cat Epic Member 5+ Years 1000 Posts

    using a conventional oil with my investigating this O ring issue is why I believe this O ring does fail .

    on the oil you must do a study of oil viscosity . the 5w is when the oil is cold the 30W is when the oil is hot. so the only difference is when the engine is cold the 5w flows faster than the 10W . when the temp drops below 20deg F the 10W will cause the engine to use more battery power to crank engine and the oil flow slower. using oil thicking products on a hi mile engine that has used conventional oils or mixes of synthetic and conventional will quiet down a worn engine but cause flow problems in cold weather .

    since it is high miles if you can do the job replace the O ring . if NOT then you will have to decide what to do next .. If it is the O ring it will gradually get worse. what you could do is try using bars engine oil stop leak in the oil . see after a few hundred if the oil pressure improves on cold start. I have used this before it does stop oil leaks due to rubber seal shrinking ... I do use it on my 1996 ...time is the killer on rubber parts.
     
    loaded94 likes this.
  6. loaded94

    loaded94 Rockstar

    I really don't drive it when it's real cold out. And it has a cord for block heater, which, I should prolly start using when it IS cold. I'll have to replace that O-ring, and as long as it it IS tore down that much, might as well do oil pump too, found them on ebay.......just over $50.00
     
  7. j cat

    j cat Epic Member 5+ Years 1000 Posts

    I would try that bars stop leak before any wrenches start flying around . taking apart an engine with close to 300K will be a PITA..
     
    RayVoy likes this.
  8. loaded94

    loaded94 Rockstar

    Oh, I WILL. Can it be added to a full oil supply?

    AND since I recently bought this with high miles, I started using Valvoline Max life, which is a synthetic blend, they say switching to synthetic from reg oil can cause seal leakage, so, I'm hoping that's all it is...........................
     
  9. RayVoy

    RayVoy Rockstar 4 Years 5000 Posts

    That's an "old wives tale", why would a different formula cause seals to leak?

    It's the same "old wives tale" that claims you'll burn oil if you change brands.

    The same one that says you need to change your oil every 3,000 miles.
     
  10. loaded94

    loaded94 Rockstar

    lol, wasn't sure about that one either, but, seems like everyone believes it, lol. Tried the Bars, we shall see, next step will be the oil sending unit.
     

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