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Any auto thermostat experts? Is Dex Cool to blame?

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24 comments

  • fatwiteguy
    I have a 98 chev pickup and the manifold started leaking, had to have it removed and shaved down, 700.00. Mechanic says he sees alot of this with the dexcool. I'm back to the good ole green antifreeze.
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  • dheffley
    Before you do anything, get the temp sending unit checked to see if it is bad, I had one go out and it always showed the motor was cold. Had another one go out and it always showed th motor was hot. In both case the temp was fine.
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  • rovrman
    Dex-cool is not to blame.....sensor, thermastat.
    I seen ALOT of problems whn people mix dex-cool with regular antifreeze.
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  • idsman75
    I didn't mix and know that's a no-no. Ya can't mix em or things will REALLY gum up. You have to do a COMPLETE THOROUGH flush when switching from one to the other. I've heard horror stories about that.

    I'm just wondering if it will be bad for my system (aluminum radiator) if I switch back to the green stuff.
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  • dheffley
    quote:Originally posted by idsman75
    I didn't mix and know that's a no-no. Ya can't mix em or things will REALLY gum up. You have to do a COMPLETE THOROUGH flush when switching from one to the other. I've heard horror stories about that.

    I'm just wondering if it will be bad for my system (aluminum radiator) if I switch back to the green stuff.


    Green stuff won't hurt aluminum unless it's aluminum with expoxied on black plastic tanks. The black plastic tanks and the epoxy degrade with the green stuff.
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  • KSUmarksman
    dexcool should have a heat capacity similar to regular green stuff,
    probably a sensor issue
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  • dcloco
    You have a bad thermostatic fan clutch.

    I did not read any of the replies, if somebody already mentioned this, I apologize.
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  • CHEVELLE427
    could be another bad thermostat, even the brand names are junk now days [:(]
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  • Warpig883
    I am in the dexcool class action lawsuit. I will probably only get $5 for all the repairs it caused me.
    Google it if interested.
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  • idsman75
    I've Googled it and there are just as many people on each side of the Dex-Cool debate.
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  • jwb267
    i started out with the orange stuff, then i read where prestone was compatiable with all and that's what i have been using for several years. never did flush the radiator. (96 corsica with over 200K miles)
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  • Forkliftking
    quote:Originally posted by fatwiteguy
    I have a 98 chev pickup and the manifold started leaking, had to have it removed and shaved down, 700.00. Mechanic says he sees alot of this with the dexcool. I'm back to the good ole green antifreeze.

    Had the same problem with my '98 GMC. Intake gaskets blew out. Luckily I was only about 1/4 from my shop. I killed the engine and coasted in. Dealer says the gaskets were a known default, but GM decided not to put a recall on this problem. Gaskets cost me about $40 and 3 hours of my busy day. I'll never buy another GMC.
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  • 1911a1-fan
    the "check engine light" has nothing to do with your engine coolant, it is for emissions you could drain it dry of coolant and oil that light should not be triggered until an emission trigger or knock sensor was hit {as you blew the engine but you get the point}



    and with temperature outside my 96 g30 never reaches full temp right now is not the time to trouble shoot it
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  • HandLoad
    Dunno if this is still possible in the newer ones, but all three of my older GMs at one time or another, blew the voltage regulator for the instrument package - Oil pressure looks high, fuel stays too high, and the temp always looked low while running in this condition.

    This was in 1992-3-4 pickups/blazers.
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  • RUGERGUNZ
    I have a 94 S-10 4WD w/4.3L engine.

    I run the green antifreeze. I would have to change the thermostat (a 195* model) at least once a year because the engine would run too cold. When I installed the new thermostat the temps would run normal under any conditions and then just would run cold again, and then it was time to change the thermostat.

    I figured it was worth replacing the thermostat often because they are cheap.

    Dcloco said " You have a bad thermostatic fan clutch." Well not too long ago I found mine was bad, had been bad for along time I think. So I changed it out. Everything ran fine and no need for new thermostats.

    BUT, beware a very short time after putting on a new fan clutch the waterpump went. I think it was the extra strain of actually having the fan run.




    I would recommend changing the waterpump, fanclutch, thermostat, and belt at the same time and think that you would have the problem fixed without having to change coolants.

    Here is where I get my parts for the best price and have been extremely happy with them. http://rockauto.com/
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  • haroldchrismeyer
    quote:the "check engine light" has nothing to do with your engine coolant

    The check engine light can be related to a thermostat staying open. If the engine doesn't get to a predetermined temperature in a predetermined time, the computer knows the thermostat is not working. It isn't caused by Dexcool. Neither was that intake and head that had to be resurfaced. The newer Dexcool is fine, but shouldn't be mixed with anything else. I have it in my truck, and when there is a problem it will get the same. The fan clutch cannot cause the engine to run cold. The only way the fan cools the coolant is if the coolant is in the radiator. The thermostat is what controls this. Fan clutches do go bad, but how much do you think the fan actually does after thirty miles per hour?? Nothing.
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  • Warpig883
    quote:the "check engine light" has nothing to do with your engine coolant

    It will come on when coolant gets into a cylinder and causes a miss.

    Everytime I had a dexcool related leak my low coolant light came on.
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  • pitbud5
    Dex cool is to blame for clogged heater cores in GM's other than that............we use it all the time in all makes and models of cars
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  • 1911a1-fan
    quote:Originally posted by haroldchrismeyer
    quote:the "check engine light" has nothing to do with your engine coolant

    The check engine light can be related to a thermostat staying open. If the engine doesn't get to a predetermined temperature in a predetermined time, the computer knows the thermostat is not working. It isn't caused by Dexcool. Neither was that intake and head that had to be resurfaced. The newer Dexcool is fine, but shouldn't be mixed with anything else. I have it in my truck, and when there is a problem it will get the same. The fan clutch cannot cause the engine to run cold. The only way the fan cools the coolant is if the coolant is in the radiator. The thermostat is what controls this. Fan clutches do go bad, but how much do you think the fan actually does after thirty miles per hour?? Nothing.



    check engine or service engine soon has zip nada none to do with anything else but emissions, it doesn't care if you remove the thermostat, or block it off, unless it effects a knock sensOr,egr valve, o2senser, etc


    quote:Originally posted by Warpig883
    quote:the "check engine light" has nothing to do with your engine coolant

    It will come on when coolant gets into a cylinder and causes a miss.

    Everytime I had a dexcool related leak my low coolant light came on.


    again coolant getting into a cylinder would effect the emissions from the fuel cap to the engine, and out the tail pipe is all it cares about nothing else unless it directly effect the emissions

    LOOK IT UP
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  • stetson
    Just went through this with my son's 99 VW bettle.The garage put in
    the wrong anti-freeze and left towels in cooling system when they
    replaced the water pump.Luckily ,I have all the paperwork and parts
    so they are going to pay me back for repair$1491!
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  • idsman75
    quote:Originally posted by 1911a1fan
    the "check engine light" has nothing to do with your engine coolant, it is for emissions you could drain it dry of coolant and oil that light should not be triggered until an emission trigger or knock sensor was hit {as you blew the engine but you get the point}



    and with temperature outside my 96 g30 never reaches full temp right now is not the time to trouble shoot it


    Actually, the code referred to a cooling system problem. An engine that runs too cold does not burn fuel as efficiently. Anything involving environmental impact can cause a Check Engine light to come on. My brother just had his come on because of a mucked up EGR.
    0
  • idsman75
    quote:Originally posted by RUGERGUNZ
    I have a 94 S-10 4WD w/4.3L engine.

    I run the green antifreeze. I would have to change the thermostat (a 195* model) at least once a year because the engine would run too cold. When I installed the new thermostat the temps would run normal under any conditions and then just would run cold again, and then it was time to change the thermostat.

    I figured it was worth replacing the thermostat often because they are cheap.

    Dcloco said " You have a bad thermostatic fan clutch." Well not too long ago I found mine was bad, had been bad for along time I think. So I changed it out. Everything ran fine and no need for new thermostats.

    BUT, beware a very short time after putting on a new fan clutch the waterpump went. I think it was the extra strain of actually having the fan run.




    I would recommend changing the waterpump, fanclutch, thermostat, and belt at the same time and think that you would have the problem fixed without having to change coolants.

    Here is where I get my parts for the best price and have been extremely happy with them. http://rockauto.com/


    You run the green but they didn't switch to the aluminum radiators until '96 which is what Dex-Cool was designed for.
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  • idsman75
    quote:Originally posted by 1911a1fan
    quote:Originally posted by haroldchrismeyer
    quote:the "check engine light" has nothing to do with your engine coolant

    The check engine light can be related to a thermostat staying open. If the engine doesn't get to a predetermined temperature in a predetermined time, the computer knows the thermostat is not working. It isn't caused by Dexcool. Neither was that intake and head that had to be resurfaced. The newer Dexcool is fine, but shouldn't be mixed with anything else. I have it in my truck, and when there is a problem it will get the same. The fan clutch cannot cause the engine to run cold. The only way the fan cools the coolant is if the coolant is in the radiator. The thermostat is what controls this. Fan clutches do go bad, but how much do you think the fan actually does after thirty miles per hour?? Nothing.



    check engine or service engine soon has zip nada none to do with anything else but emissions, it doesn't care if you remove the thermostat, or block it off, unless it effects a knock sensOr,egr valve, o2senser, etc


    quote:Originally posted by Warpig883
    quote:the "check engine light" has nothing to do with your engine coolant

    It will come on when coolant gets into a cylinder and causes a miss.

    Everytime I had a dexcool related leak my low coolant light came on.


    again coolant getting into a cylinder would effect the emissions from the fuel cap to the engine, and out the tail pipe is all it cares about nothing else unless it directly effect the emissions

    LOOK IT UP



    I did look it up:

    http://autorepair.about.com/library/ts/obd-i/bl-dtcs-56.htm
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  • 1911a1-fan
    http://autorepair.about.com/library/ts/obd-i/bl-dtcs-56.htm

    thats a obd code, totally different that just the light coming on while running



    quote:Actually, the code referred to a cooling system problem. An engine that runs too cold does not burn fuel as efficiently. Anything involving environmental impact can cause a Check Engine light to come on. My brother just had his come on because of a mucked up EGR.

    egr valve is a part of emissions

    edit:read what you have to do to pull that code out, it is totally different that the light coming on while driving, that is a FORCED code, the check engine light will not come on for any other reason while running except for emissions
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