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My blazer is smoking and I dont know why

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by BayouBlazer88, Aug 1, 2002.

  1. BayouBlazer88

    BayouBlazer88 1/2 ton status

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    My blazer always shoots out white smoke at startup but I know thats just oil seaping through the valve seals. Yesterday I tried pulling my boat and it started to constantly shoot out small amounts of white smoke. However, when I took the boat off and ran it for a while the smoke stopped. I also have a small oil leak and when I checked it, it needed about a quart. Is the white smoke from lack of oil or did I blow a head gasket?
     
  2. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Generally oil smoke is blue, fuel (too rich, flooded etc) is black and coolant or water produces white smoke.

    Rene
     
  3. BowtieBlazer

    BowtieBlazer 1/2 ton status

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    Let me chime in a bit on this one as well since I saw the smoking incedent. On startup the smoke is a grayish whitish blueish type of thing. Nothing black this is a tbi 88 350 runs clean for the most part 126+ thousand. replaced O2 sensor about a month ago. We hooked the boat up, he gassed it a hair and light blue smoke slightly came out the pipes. We get to leaving and it begins to look white, pulled over checked oil registered maybe a quart low, get up to about 45mph the whole way up to 45mph its smoking what looked to be white or grey or something...maybe oil and water? after running about a mile or so down the road it stops smoking as badly I guess because we leveled off at crusing speed. Oil pressure is reading about 45+ psi, temp a flat 160. My theory is that its a head gasket or ring going bye bye, Guess next will be to hook up a compression guage and check it out. No harsh abuse up to this point just recent run in with some smoke on what should be a 350 with many miles yet to run. Advice anyone? Also should we check for oil in the radiator, or water in the oil pan?

    Matt maybe when you get back if we don't cross paths as I am off on vacation noon sunday we can run a compression check.
     
  4. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Well I'd do a compression check for sure. All should be within 10% of each other. I've also heard there are analysers you can buy that will detect exhaust gasses in the coolant. I usually look for bubbles though. The hard part is that sometimes the cavitation caused by the water pump impeller causes those bubbles.

    The smoke description strongly suggests the motor is burning some coolant though.

    Rene
     
  5. glencanyonexplor

    glencanyonexplor Registered Member

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    If you Have an auto trans check the vacuum modulator it may be leaking and the oil gets to the engine thru the vacuum line. /forums/images/icons/shocked.gif
     
  6. BowtieBlazer

    BowtieBlazer 1/2 ton status

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    wow thats a thought as well. I got a SM465 so never had to worry about that myself. Thanks!
     
  7. BowtieBlazer

    BowtieBlazer 1/2 ton status

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    Any general numbers to look for or are all vehicles diff? If I had to guess I'd say 150-165 range?
     
  8. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I'd say 120 would be on the low side, and 140-150 would be healthy. If they are all 120 that's still OK though.

    Rene
     
  9. wrathORC

    wrathORC 1/2 ton status

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    Well, is it condensation? Here in the U.P. of Michigan we still get condensation out of our exhausts in the summer. Sometimes it doesn't even go away even when we get to operating temperatures.

    Do you run antifreeze or just plain water (I have to ask this now after talking to some southerners that don't run antifreeze)? If you run some antifreeze in the system you'll definitely be able to smell burning antifreeze. If you can't smell it because you're used to it find a kid or a female and ask them. If it's real bad you'll even be able to taste it.

    Chances are if you're getting coolant burned in your exhaust then you're getting it in your oil too. Change the oil. If it looks like a melted Wendy's frosty then you've got coolant in your oil.

    For the most part oil is blue when it burns. Sometimes synthetic oil burns black though. Running really rich usually produces black smoke because of both unburned fuel and letting a lot of carbon buildup escape.

    As far as a compression test, just make sure that the high and low cylinders are within 12lbs. Compression tests are a chore to do by yourself. I did one on my truck but I forgot to prop open the primaries so I only got readings between 117 and 128. The important part is that they all are within 12-15lbs of each other.
     
  10. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Has it ever been over heated bad? Cracked heads into the chambers above the valve are not uncommon if it has been overheated. Typicaly your not going to see smoke from rings at start up. It's usually valve guide seals and head gaskets that will do that. I'm betting on the valve guide seals. With the truck on a boat ramp oil may have pooled around the valve guides seals on the low side. It was a fair amount but it was in the chamber around the valve not dirrectly into the cylinder. So the exhaust was buring it off AFTER the combustion chamber.
    Check the plugs. If they have a few k on them then the oil buring will have formed edeposits on them. It will be a hard whitish gray or even a little yellow looking junk that will chip off if it's light oil consumption. More oilly and black if it's a lot.
    If the compression check comes up good and you run the test Rene' spoke of to check for exhaust in the coolant and it shows none you looking at a fairly easy and cheap repair of just the valve guide seals.
    NAPA has the kit for the coolant test.
     
  11. BigJim85

    BigJim85 1/2 ton status

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    Sounds like the problem I had with my 305, except mine just burnt oil. It would only blow smoke right after start-up until it got warm then quit. But putting the pedal down and running the engine hard would spit some smoke out too. I'm pretty sure it was because my engine was pretty well abused before I got it. 180 thou miles, or more likely 280+ is on that thing. Didn't have a working oil pressure sender until recently and boy was I shocked, 10-15 psi and lower. I'm surprised it ran at all, and when I took the intake off after pulling it the inside looked like the bottom of a charcoal grill. I gotta say though, that gutless wonder ran till I took it out.
     
  12. BowtieBlazer

    BowtieBlazer 1/2 ton status

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    Still unsure of the abuse it saw before Matt got the truck. The previous owner pulled a large camper from what it sounds like fairly often. If you saw the truck its a highly maintained vehicle.

    I am a bit confused about sitting on the boat ramp... It never made it to the boat ramp we shut it down rather than towing on a possible wound...It belched the smoke after it had been idling and running a good 10+ minutes.

    At one point I thought I could smeel a bit of coolant. Almost positive I did. I am waiting to hear from him but best bet will probably be compression check and draining a little oil to see. /forums/images/icons/confused.gif
     
  13. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    I ran a 350 with 3psi At idle for a year and it never rattled a lifter /forums/images/icons/smile.gif
    Going down the hwy 15-20 max with 20w50. Ran fine the day I pulled it but the presuure was getting progresivly worse. Main bearings were done I thing the trucst bearing was bad and it let the crank walk.
     
  14. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    That's starting to sound like blown HG or cracked head. If it's blown head gasket or cracked head on an intake side the plug in the cylinder(s) where the coolant is getting in will be unusualy clean compaired to the rest.
     
  15. BigJim85

    BigJim85 1/2 ton status

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    Damn. Mine chattered quite a bit, 20w50 helped early on but near the end it was quite bad and thick oil didn't even help. Havn't opened it up yet, still trying to get the new one in line and in my truck. Can't wait to see how bad that thing is.
     

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