Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

NO oil pressure?!?!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Indy, Jun 29, 2003.

  1. Indy

    Indy Registered Member

    Joined:
    Nov 18, 2002
    Posts:
    6
    Likes Received:
    0
    Location:
    Reno, Nevada
    I've got an 88 K5 w/ a 350 TBI centerbolt. Recently, I've begun losing oil pressure when the truck is warmed up and at idle. It'll go all the way down to 0 psi, and if I put it in neutral and rev it to about 1500 I can keep it at about 15 psi. I replaced the pump with a high volume pump and new oil pan gasket, didn't solve the problem. Could it be my timing? The oil looks good, so I don't think it's a head gasket problem. Any help is appreciated. Thanks-Indy
     
  2. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    I sure hope you aren't driving it like this. /forums/images/graemlins/eek.gif I'd first test with a known-good oil pressure gauge. If the pressure is really dropping that low, the lifters should start ticking like crazy when it drops to zero. (And the engine probably doesn't have much time left). /forums/images/graemlins/frown.gif If a test gauge says that the pressure is OK, then you'll need to troubleshoot the gauge and sender circuit.

    But if indeed the pressure is that low, even with a high volume pump, then it's time to go inside the engine. Wasted bearings or an internal plug that has fallen out are the most likely problems that you'll find. /forums/images/graemlins/frown.gif
     
  3. Indy

    Indy Registered Member

    Joined:
    Nov 18, 2002
    Posts:
    6
    Likes Received:
    0
    Location:
    Reno, Nevada
    That's kinda what stumped me is that the lifters are not ticking, and I've only got about 3,000 miles on a rebuild. Thanks for the tip, though, I'll find a good gauge to test it with.
     
  4. 87BrnRsd

    87BrnRsd 1/2 ton status

    Joined:
    Apr 21, 2003
    Posts:
    2,457
    Likes Received:
    0
    Location:
    Boone, North Carolina
    I second the idea of finding a good gauge. The reason I say this is because on an 88 K5, when the engine drops to 4 psi, the computers will automatically shut the engine off. So if the guage is reading 0, and its still running, something is wrong with the guage. You might need a new sender unit or something like that. A sunpro oil pressure guage is only 16.99 at autozone complete with everything you need to bolt it in. The only problem with that is that the place you need it to bolt in at is in a hard to reach place if the engine is in the truck. I put mine on Friday, and got the engine in yesterday so it was easy. Also, if you do put a new guage in, make sure the plastic tubing that goes from the engine to the guage, that you have to run yourself, isnt crimped anywhere. It is really easy to crimp it right at the engine, and trying to find those tiny little 1/8's ferrule nuts, which you will need if you crimp the wire since the guage only comes with the amount you need without messing up, and they cant be re-used, is a PITA.!! Just ask me because I did that, and it took 2 hours of driving around to find anything similiar. Turns out that ACE Hardware has them though. /forums/images/graemlins/thumb.gif Anyways, if you put a new guage in and it still reads 0 psi and runs, then a computer is probably messed up too, which will ad to your no psi problem. /forums/images/graemlins/angryfire.gif What kind of warranty came with the re-build and how much was the re-build??
    -Harrison
     
  5. Indy

    Indy Registered Member

    Joined:
    Nov 18, 2002
    Posts:
    6
    Likes Received:
    0
    Location:
    Reno, Nevada
    Think I got it solved. I replaced the sending unit, which on mine is at the back of the block by the O2 sensor, and it's holding at 30 psi at idle now. Thanks for your help guys!
     
  6. 87BrnRsd

    87BrnRsd 1/2 ton status

    Joined:
    Apr 21, 2003
    Posts:
    2,457
    Likes Received:
    0
    Location:
    Boone, North Carolina
    No problem. Good to hear you got it fixed. /forums/images/graemlins/thumb.gif
    -Harrison
     

Share This Page