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Chevy 6.2 Diesel

Discussion in 'Chevy Trucks' started by DJs Lawncare, Oct 14, 2004.

  1. DJs Lawncare

    DJs Lawncare Member
    Messages: 90

    I have an 88 Chevy K3500 truck with the 6.2L Diesel. The oil pressure seems to drop down to about 8-10 lbs at idle. When you are driving it, it seems to be around 25-30 lbs. Should I be concerned about this or is this just normal. It has about 97,000 miles on it. I picked it up last year. It seems to be a good truck other thatn the oil pressure and that it doesn't seem to have much heat during the winter. The heat problem is something else that I would like to know about.
  2. The Boss

    The Boss 2000 Club Member
    Messages: 2,099

    My friends dad had a scottsdale with the 6.2 diesel. It sounded like a broken washing machine but it ran great. His did the same thing. Low oil pressure at idle, higher when driving. Perfectly normal. As far as the heat goes, you might have a bad heater core. :waving:
  3. crashz

    crashz Senior Member
    Messages: 256

    What oil are you running in it?

    The heat issue is probably just the theromstat. Those 6.2L radiators are huge and will dump all of the engine's heat if the thermostat is stuck open.
  4. DJs Lawncare

    DJs Lawncare Member
    Messages: 90

    I am running 10w30 in it. I put a 190 thermostat in it last year and it didn't seem to help. It had a 185 before. The hose going into the heater core feels to be about the temperature as the one coming out of the heater core. I just flushed it this year so I don't know whether that worked or not. The truck has heat when it is 40 degrees and warmer. It hasn't gotton cold enought to find out if it is working any better now, yet.
  5. Mebes

    Mebes Senior Member
    Messages: 451

    You Got A/C in that truck?
    Some of them had a blocking valve on the heater core. (in the heater core line with a cable hooked to it)
    Maybe it's stuck.

    Feel your upper radiator hose (near the radiator not the engine) as the engine warms up it should be cold until the engine warms up, and then you should feel a surge of hot as the thermostat opens up.

    If the upper radiator hose feels like it is slowly getting warm than your thermostat has probably failed.

    I have seen quite a few thermostats bad right out of the box.
  6. crashz

    crashz Senior Member
    Messages: 256

    The 6.2s have to have either straight 30 weight (only good for the deep South) or better yet 15w-40. Both my old 6.2s ran for hundreds of thousands of miles on 15w-40. Clean as a whislte, and each one ran beautiful until the bodies rotted off of the trucks (one even out lasted the frame!). With a good block heater, the 15w-40 won't give you starting issues in the cold.
  7. DJs Lawncare

    DJs Lawncare Member
    Messages: 90

    I haven't had any problems with the starting last year in the cold with 10w30. It has a slightly rough idle. However I don't have a block heater, so I don't know how the truck would run with 15w-40. All it has is the glow plugs.
  8. crashz

    crashz Senior Member
    Messages: 256

    My guess is that the truck will start the same with 15w-40 as it does now. You'll deffinately see much improved oil pressure in the warmer months.
  9. DJs Lawncare

    DJs Lawncare Member
    Messages: 90

    Ok I guess I am not worried about the oil pressure, but I am still at a loss on the heat thing. The outside temp dropped down to like 20-25 degrees a couple nights ago. The air that was coming out of the heater was cool, maybe 50 or 60 degrees. Like I said I changed the thermostat & flushed the heater core and radiator. Both heater hoses feel equally warm. I actually have to drive the truck to make it warm up enough to open the thermostat. The temp runs between 195-210. Will covering the radiator do anything?
  10. derekbroerse

    derekbroerse 2000 Club Member
    Messages: 2,377

    Are you getting proper airflow thru the correct vents? ie: blockage, vaccuum powered flaps not opening etc.

    Maybe you can pull the cover off the heater core below the dash and a) check for plug-ups and b)feel the core to see if it gets warm
  11. gpin

    gpin Senior Member
    Messages: 390

    I know you flushed the heater core but it could still be partially blocked. They start clogging up at the bottom and gradually choke off. If the truck is over 10 years old, I'd go for a new heater core.
  12. Mebes

    Mebes Senior Member
    Messages: 451

    What do the hoses to the heater core feel like?
    Both hot?
    1 cold 1 hot?
    Both cold?

    I had a buddy with a plugged heater core a few years back on his Dodge.
    We disconnected the heater core lines from the engine and hooked 1 up to the garden hose at work.
    It shot out a bunch of crap, and the heat worked good after that.
  13. ShannonS

    ShannonS Member
    from IOWA
    Messages: 96

    Try a piece of cardboard in front of the radiator, I know our Mack's only run 180. So we throw some cardboard in front of it and they warm up nice and good. Or the other thing i thought since it don't get warm is a, not enough coolant, b thermostat is too low. Try a higher one but I am not to sure about that last part. But maybe it would have to run hotter before it opened.