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Auto repair question

  1. May 3, 2008 #1
    Just in case anyone has personal experience: This pertains to a early 90s buick regal with the 3.8L V6.

    I know there are a couple of gearheads on here and engineers but I didn't want to relegate this to one of the engineering forums so here goes. I'm trying to help a friend whose oil cooler lines tore last week. These lines are soft aluminum for a couple of inches as they lead out of the engine, then they're heat shielded rubber around a sharp bend, and then aluminum the rest of the way until feeding into the radiator. So it's the rubber that broke:
    [​IMG]
    Right there where it meets the metal. If you can't tell the rubber is crimped to the tube by some kind of industrial process.

    Now I have a two options.

    1. Replace entire oil cooler hose, including metal. This involves unbolting the old one from under the engine case and from the radiator. Neither locations are easily accessible but it is feasible.

    2. Hacksaw off the crimped part of the metal tube and just replace the rubber hose. I would use hose clamps like these:
    [​IMG]
    to secure and seal the hose to the metal tubes.

    Option 1 is the pragmatic and safest option but also the most annoying because of having to unscrew a couple of nuts in some very annoying places.

    Option 2 is more convenient and cheaper but then again money isn't really an option.

    My only concern, and the reason I post this thread, is whether using those clamps I could over torque the screw and clamp the soft aluminum tube closed. I was actually at the junkyard and while searching for replacement hoses saw this on one of the cars. There's also a post on about.experts.com about someone having luck with this method.

    So engineers, physicists, gearheads: is the amount of force the hose clamp needs to apply to seal to the tube enough to crimp the tube?

    Theres actually another very exotic option that would be worth trying just because it would very cute if it worked using parts from a later iteration of this engine. I can expound on it if anyone is curious and will to bearing with my vague language.
     
    Last edited: May 3, 2008
  2. jcsd
  3. May 3, 2008 #2

    wolram

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    The jubilee clip is a wonderful invention, just (nip) it up until you see a slight indentation in the hose, run the vehicle and check for leaks, if there are leaks tighten the clip 1/4 turn
    at a time.
    Make sure the clip is on the hose at least 1/4 inch.
     
  4. May 3, 2008 #3
    yea i was just reading a post on another forum about doing this exact thing but they recommend not cutting the crimped part completely off but just the crimping and then securing new hose to the reinforced and flared line under the crimping.

    i thought the lines weren't under pressure but apparently they are.
     
  5. May 3, 2008 #4

    wolram

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    I would go with that.
     
  6. May 3, 2008 #5
    I've got another auto question for you guys. My 96 Acura gets hot in stop and go traffic, but if I turn on the AC, the engine temperature drops immediately and seems to stay at the proper temperature. It seems to be fine when on the highway, except if I have to stop for a while at an exit, then it gets hot. I've had the thermostat and temperature sensor replaced, and had the radiator bled to check for air in the lines, and it still seems to do the same stuff. Any suggestions?
     
    Last edited: May 3, 2008
  7. May 3, 2008 #6

    wolram

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    Have you tried a new radiator cap? this item is so often over looked but it is a vital part of the cooling system.
    The next step i would take is a compression test.
     
  8. May 3, 2008 #7
    turn the ac on cold or hot? have you had the radiator fan checked?

    edit

    he'd have a lot more obvious problems if he had a warped head though a warped head he will get if he doesn't figure it out soon.
     
  9. May 3, 2008 #8

    wolram

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    Yes a leak can occur from cylinder to water way, that is exactly what is happening to mine
    it will run all day at a steady cruise but stop at lights and the water temp shoots up.

    A pressure test on the cooling system as well as a cylinder compression test should nail the problem, if a new cap does not.

    And yes the fan is the second thing to check before elaborate tests.
     
    Last edited: May 3, 2008
  10. May 3, 2008 #9
    but then you have a warped/cracked head? there should be other signs of this like trouble starting when cold.
     
  11. May 3, 2008 #10
    Fans seem to run fine, with or without the AC on, had those checked. Blown head gasket should mean decreases in the radiator fluid levels correct, which I don't believe to be happening, although I'm a little afraid to check in case it is the case. There was plenty of radiator fluid last time I checked. What is the cost to fix if is a crack in the cylinder? I'd much prefer just to replace the radiator cap :) Could it be just a crappy radiator?
     
  12. May 3, 2008 #11
    ha a crack in cylinder will cost you your life. a warped head ~ 2k
     
  13. May 3, 2008 #12

    wolram

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    It could be the cooling system needs flushing, but i am sure that would show up as a general over heating problem, change the cap first, and make sure your fan belt is adjust correctly,if these prove ok then get the cooling system pressure tested, it will only take a few minutes and should not cost much, of course you could have a vulture blocking your air flow to the radiator, but i am sure you checked for such things.
     
  14. May 3, 2008 #13
    No varmints on the grill. It could well need a fan belt, I've never replaced it, so it's been at least 50k possible 135k with same belt. curious, why check the cooling system pressure. Could it be a water pump gone bad? Also expensive. . .


    edit: Just checked the coolant level, exactly where it was ~ 2 months ago.. .
     
    Last edited: May 3, 2008
  15. May 3, 2008 #14

    wolram

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    A bad water pump should be obvious, noise, leaking water, a cooling system pressure check
    will show up any leaks, even internal ones, remember water needs pressure to stop it boiling
    and your cap is the regulator for that pressure.
     
  16. May 3, 2008 #15

    OmCheeto

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    Sounds very similar to my '95 Chrysler Lebaron, which actually is powered by a Mitsubishi engine.

    The reason the temperature drops when you turn on the AC is because the radiator fan is electronically controlled. Any time you turn on the AC, the fan will remain permanently on. Turning off the AC will cause the fan to be controlled by a temperature sensor. While driving the car, there is enough wind across the radiator to keep the engine cool. But at a stoplight: no wind = no cooling = overheated engine.

    It sounds as though your temperature sensor system has gone as haywire as mine. Any time I drive around town, I have to leave the air conditioner on. Except that the car is a convertible and I thought an air conditioner in a convertible is about the most wimpy thing in the world so I took the fan belt off that drives the AC compressor. So the AC really isn't on, the car just thinks it is. The AC button now acts as an engine cooling button until I stop being so cheap and get the darned sensor circuitry fixed.

    Hope that helps. :smile:
     
  17. May 3, 2008 #16
    ha thats a clever fix
     
  18. May 3, 2008 #17
    I had the temperature sensor replaced about a year ago, well at least they said they did. I really don't trust the guys to do anything though, it was a Firestone or something like that and they really didn't instill confidence, at all.

    Ok so fan belt, radiator cap, cooling system pressure check, temperature sensor all things to check. Thanks for all the help, gotta love PF. One stop shop for all your automotive and physics needs :)
     
  19. May 3, 2008 #18

    OmCheeto

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    There are probably multiple water temperature sensors.
    They may have replaced the one that feeds your dash gauge.
    If not, then the temperature sensor would definitely provide a signal through different circuits for the dash gauge and the radiator fan control. There may simply be a loose connection that they've overlooked. Though if the fan works without the AC on then I'd definitely look for a second sensor.

    I would go to the Acura dealer.
     
  20. May 3, 2008 #19
    Like Wolram said, make sure the radiator cap is in good condition first. If it's not holding good pressure the boiling temp of the water drops considerably. Have you noticed it boiling over into your coolant overflow at all?

    Another good thing to look for, especially if you believe there's a head gasket leak, is bubbles in the coolant. With the engine cold, pull the radiator cap and start the engine... look for tiny bubbles in the radiator as the engine begins to warm up. Keep a close eye on it though... when the thermostat warms up and opens, your engine,bay, or garage floor could get a good healthy dose of antifreeze.
     
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