99 SL SOHC 5 speed Pinging when warm

Discussion in 'General Motoring' started by WayneF, May 9, 2008.

  1. WayneF

    WayneF Guest

    My SL is fine when it is cold, but when it is warm it pings almost
    constantly, especially in higher RPMs. The previous owner changed the
    thermostat to a lower setting 170, I think. I also did not have any (less
    than piss warm) heat over the winter. I was wondering if these 2 problems
    are related. I do not have any service engine lights on.

    WayneF, May 9, 2008
  2. WayneF

    marx404 Guest

    oil viscosity and gas quality? thats my guess.
    marx404, May 10, 2008
  3. WayneF

    Doug Miller Guest

    You might check the coolant temperature sensor.
    Doug Miller, May 10, 2008
  4. WayneF

    SMS Guest

    One cause of pinging can be too low of a combustion chamber temperature.
    I believe that the SL engine had a 195 degree thermostat as standard
    equipment, and if so, 170 is a huge difference. You should try the
    proper thermostat. Usually people go down by 5 degrees at a time if the
    engine is running too hot, to go down by 25 degrees is a really bad idea.

    Was he having an overheating problem that caused him to put in such a
    low temperature thermostat or was he mistakenly thinking "the cooler the
    better?" Was the cooling fan temperature sensor also changed to a lower
    temperature? Some owners have had a problem of overheating when at idle
    because the electric cooling fan didn't come on soon enough, and changed
    the cooling fan sensor (though you want to be careful that it's not set
    to a level that's so low that it's on all the time).

    A lower temperature thermostat would mean that lower temperature coolant
    is circulating through the heater core, though it shouldn't have had
    that much of an effect on heat, unless you're in an extremely cold
    climate, though again, 25 degrees is a huge difference, and the heater
    was designed for higher temperature coolant.
    SMS, May 11, 2008
  5. WayneF

    -Cronus- Guest

    Please oh please cite your source for this.
    To go down at all is a bandage fix. Something a bubba like you should be
    familure with.
    Cooling fan sensor? Never heard of it.
    Set what so low? What the F#@K are you blabbing about?
    Yeah the heater was designed for high temp coolants... <roles eyes>

    Why is a guy who has NO background in automotive service and repair
    giving advice here?

    Here are the things Wayne should actually be looking for:
    --Low coolant
    --Loose drive belt
    --Restricted air flow through radiator, or restricted air flow through
    condenser (if A/C equipped)
    --Proper cooling fan operation
    (IIRC the cooling fan for the S-series should come one around 215-230
    deg if the ECT sensor is working correctly)
    --Front air dam missing or damaged
    --Knock Sensor Circuit System
    --EGR (becomes clogged)
    --Poor quality fuel (no you should not goto a higher octane fuel. It is
    another bandage fix.)

    (Stick with bicycles Steve. You're way out of your league.)
    -Cronus-, May 12, 2008
  6. WayneF

    -Cronus- Guest

    One more thing you might try is decarbonizing but go through the other
    things first.
    -Cronus-, May 12, 2008
  7. WayneF

    -Cronus- Guest

    Oh look Scharf posted again. Obviously Scharf is "pretending" to have me
    kill filtered. (Typical tactic he has been known to use.) Why else would
    he make such a lame out of the blue post after I called him on his bs.
    He's trying to change the subject... I'm not going to let that happen.
    I'm tired of him regurgitating stuff he knows nothing about.
    -Cronus-, May 12, 2008
  8. WayneF

    WayneF Guest

    Thanks for everyone's help. The car does almost have 150,000 miles. Every
    hear of seafoam and will it be a fix or make things worse. I didn't have any
    problems since it was a cooler temp outside. I don't get it! BTW The
    cooling fan comes on when I turn on the A/C.

    WayneF, May 12, 2008
  9. WayneF

    SMS Guest

    You might try higher octane gasoline. That's a workaround, but it can
    prevent pinging. It's very destructive to the engine to not stop the

    The cooling fan is supposed to come on when you turn on the AC. You must
    have sufficient airflow over the condenser at all times, even when stopped.
    SMS, May 13, 2008
  10. WayneF

    SMS Guest

    Wow a bandage fix offered up by the wannabe mechanic.
    As I said before, you have no business giving anyone any advice on
    servicing a car.
    You wrote that. That was bit of blunderous information was posted by

    I still would like to know wtf a "cooling fan temperature sensor" is and
    how you get one with a "lower temperature".

    Also a thoughtful post was already provided to the OP.
    Its a shame you couldnt see it do to your ego.
    SMS, May 13, 2008
  11. WayneF

    -Cronus- Guest

    I would use GM's Top Engine Clearer myself. I think I posted a
    walkthrough for it here in the past. Look in google groups archives.
    Saturnfans has a few walkthroughs and discussions for seafoam IIRC.

    If I were you I might start by installing a brass ECT sensor, if it has
    a plastic tipped ECT sensor, and then remove and clean the EGR and
    passages. If it looks bad then the engine should probably be
    decarbonized. (also be sure you have an air damn and an unobstructed
    -Cronus-, May 13, 2008
  12. WayneF

    SMS Guest

    One more thing, while changing the thermostat back to the proper
    temperature may help the pinging problem, it could also exacerbate it.
    It's possible that the previous owner switched to the lower temperature
    thermostat as a bandaid solution to pinging that was even worse.

    This is the type of problem where it may be worth paying a master
    mechanic to diagnose the root cause of the pinging. OTOH, trying
    inexpensive fixes such as using the proper thermostat, or changing
    fuels, may be worth a try. You can always go back to the way it was before.
    SMS, May 13, 2008
  13. WayneF

    Doug Miller Guest

    Ummmm.... no, it can't.

    Pinging occurs when the fuel/air mixture is detonated too early. You
    wanna explain how low temperatures can cause premature detonation?
    Doug Miller, May 14, 2008
  14. WayneF

    -Cronus- Guest

    (8 hours and many Scharf post later...)
    Well hows it feel to be on Scharfs kill-filter Doug?
    -Cronus-, May 14, 2008
  15. WayneF

    Doug Miller Guest

    Like I said... you wanna explain that?
    No, it's nonsense.
    Of course. But having it too low will *not* cause predetonation.
    Doug Miller, May 15, 2008
  16. WayneF

    SMS Guest

    This is what I read, "knock occurs more prevalently in too high a
    combustion temp which is why engines with aluminum cylinder heads can
    run higher compression as they dissipate heat better. But too cool a
    combustion temp can also increase knock."

    Yes, it's counter-intuitive. In any case, it's best to keep the engine
    temperature at what it was designed for.
    SMS, May 15, 2008
  17. WayneF

    -Cronus- Guest

    It took him about "24" hours to respond, nearly "5" hours after his last
    post here, but he finally found something to use as an excuse.

    He copy-pasted an excerpt from this
    02-26-2008, 02:56 PM

    Yeah who needs training, ASE certs, and facts when you can just
    regurgitate a forum posting...
    -Cronus-, May 15, 2008
Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.