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Thread: Avanti over heating

  1. #1

    Avanti over heating

    I have been having over heating problems with my Avanti. Where I am getting confused is my temperature gauge will show between 190 and 240 will vary no matter if I am going slow or on the highway. I will open my hood on the car take my temperature sensor gun and point it where the sensor is located and get a reading of 170 degrees. My temperature seems to drop every time i open the hood on my car.

    The question I have is should I rely on my temperature reading tool as to being accurate? Should I point to a different part of the engine instead of the back the head where the sensor is located?

    Rob

  2. #2
    An infrared gun will not read the same temp on the head as the water inside the head. You have air cooling the outside metal of the head, heat transfer to and from the rest of the engine and other factors at play.

    Is the coolant boiling? A bad connection at the sensor will make it read hot. Best test of the sensor is to pull it out of the block, hook it up in a pan of boiling water and get the reading. For temps other than 212F you can use a good thermometer for comparison in the water.
    Jim
    Often in error, never in doubt

    ____1966 Avanti II RQA 0088_______________1963 Avanti R2 63R3152____________Rabid Snail Racing

  3. #3
    The coolant has not been boiling. Sounds like the gun in not accurate. Maybe I should pull my freeze plugs out and flush the block. Sounds of it I might have some sludge in my cooling passages?

  4. #4
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    Think I'd just put in a new sender. If it's not pushing coolant out of the surge tank, it's not really overheating, at least not that badly. Pulling freeze plugs on an Avanti with the engine in the car is no easy task!!!! Sender--- cheap-easy, freeze plugs hard. And you could be reallly lucky and find the connector or the wire is bad especially the way it hooks up, can easily work the wire and break the insides after 45+ years. Then won't even have to pull the sender !! What does your heat gun show at the surge tank?

  5. #5
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    Search the forum for input on installing a air deflector on the lower radiator support bracket. Cleanig the block is a great idea, don't fret when you pull out pieces of wire, it's just left over from when the bock was cast. The air deflector aids in sucking the heat down and out of the engine compartmant. I used a Satun station wagon deflector.
    Richard

  6. #6
    I am reading 180 degrees at the surge tank.

  7. #7
    Senior Member Corvanti's Avatar
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    i had to replace the sending unit wiring on my avanti to the temp gauge... i'd go w/a bad sending unit or wire/connector being the problem.

    FWIW: i also put in a 160 degree thermostat - helped in short distance city traffic. and i installed a 90's saturn wagon air dam, i think it was from a sc2, but not positive. easy install... after all that, never went above 200.
    '40 Champion DeLuxe

    '63 Avanti R-1384. sold 12/10.

  8. #8
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    Quote Originally Posted by rmpineiro View Post
    I am reading 180 degrees at the surge tank.
    Then It's close to normal inside. Go for the sender wires and sender.

  9. #9
    Senior Member Gunslinger's Avatar
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    I have the Saturn air deflector installed on my car...makes a nice difference on the open road...no value when idling with no air movement. It's all up to the fan when not in motion.
    Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, cocky and in general a malcontent.

  10. #10
    Gunslinger: Can you post a picture of the Saturn air deflector mounted on your Avanti? Thanks. stupak

  11. #11
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    A Saturn air dam was being considered for our Avanti in Florida, but now that I am in the NE I don't need it. The car was in the Everglades City parade every summer and as it was only about a mile long it worked out...glad it wasn't two miles! I used a "wetting agent" in the coolant. It has been a while, but I think it was Purple Ice.

    I don't know if Saturn air dams varied much, but someone mentioned on the forum that the 1996 Saturn's air dam worked well. #21031161

  12. #12
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    Quote Originally Posted by Bob Bryant View Post
    A Saturn air dam was being considered for our Avanti in Florida, but now that I am in the NE I don't need it. The car was in the Everglades City parade every summer and as it was only about a mile long it worked out...glad it wasn't two miles! I used a "wetting agent" in the coolant. It has been a while, but I think it was Purple Ice.

    I don't know if Saturn air dams varied much, but someone mentioned on the forum that the 1996 Saturn's air dam worked well. #21031161
    Correct Bob

    Here's the post of the installation on my 83 Avanti

    https://forum.foobar.c...1-Installation

    Bob
    ,

  13. #13
    Senior Member Gunslinger's Avatar
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    That's the deflector I have...easy install and not expensive. The part at a GM dealer is less than $30. I also used a length of flat bar aluminum to attach it with to the radiator support.
    Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, cocky and in general a malcontent.

  14. #14
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    Quote Originally Posted by Bob Bryant View Post
    A Saturn air dam was being considered for our Avanti in Florida, but now that I am in the NE I don't need it. The car was in the Everglades City parade every summer and as it was only about a mile long it worked out...glad it wasn't two miles! I used a "wetting agent" in the coolant. It has been a while, but I think it was Purple Ice.
    I don't know if Saturn air dams varied much, but someone mentioned on the forum that the 1996 Saturn's air dam worked well. #21031161
    In Florida the Avanti would be in the Fourth of July parade every year. That is a hot place in July! Probably about a mile long parade in 90 plus temps.. Yesterday, in Groton it was around two miles and 85F. My car was running about 15 degrees warmer than I would have expected. When outcomes change I try to think of what is different. I changed coolant and did not add the wetting agent this year. It will be added and I will post later the apparent results of my amateur's effort at research! Hope you all had a great Fourth. Several club members said they would no longer participate in parades. Received many favorable comments on the Avanti along the parade route. One was funny..."It looks like the Batmobile!"

  15. #15
    Senior Member Lenny R2's Avatar
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    On my 63R2 i had a overheating problem,i have the Saturn airdam,new clutch fan,bigger tubes in the radiator,new waterpump
    3,000 CFM electric fan ,new temp sensor,new thermostat&the last thing i did finally cured it.Jon Myer told me to drill out the
    thermostat bypass hole to 3/4.It use to heat up at red lights&stop&go traffic but now finally ok.
    Lenny
    Atlanta, GA


  16. #16
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    Quote Originally Posted by Bob Bryant View Post
    In Florida the Avanti would be in the Fourth of July parade every year. That is a hot place in July! Probably about a mile long parade in 90 plus temps.. Yesterday, in Groton it was around two miles and 85F. My car was running about 15 degrees warmer than I would have expected. When outcomes change I try to think of what is different. I changed coolant and did not add the wetting agent this year. It will be added and I will post later the apparent results of my amateur's effort at research! Hope you all had a great Fourth. Several club members said they would no longer participate in parades. Received many favorable comments on the Avanti along the parade route. One was funny..."It looks like the Batmobile!"
    Being highly tech savvy is not my claim, but adding Purple Ice "wetting agent" to the coolant appears to lower operating temperature of my Avanti around 10-15 degrees. I could not duplicate the previous conditions exactly, but there appears to be a lowering that was beneficial. It will not compensate for a clogged radiator and/or block. A shop in Naples built high performance engines and the owner said he wanted the product in every engine that left his shop. It appears to be beneficial. Redline has a wetting agent in its line and there may be others. It took a little while to find a place that carried it in stock.
    Last edited by Bob Bryant; 07-09-2011 at 06:10 PM.

  17. #17
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    Been going round and round with my newly rebuilt 63 Daytona 259 cooling. Stop n go traffic in Los Angeles is brutal, especially in summer. With the stock cleaned out radiator (2 row), Avanti clutch fan, normal antifreeze mix and a 180 thermostat it overheated badly (pegged the gauge, read 230 on the laser therm on the water outlet). It went to full scale at 70MPH as well.
    Changed to a high flow 160 thermostat, drained the system and used water with a bottle of water wetter. Took longer to heat up, still went full scale in traffic but topped out at 220.
    Installed an aluminum radiator https://forum.foobar.c...tor-conversion and the temp went way down - still went to the top of the gauge in heavy traffic but stayed at 3/4 scale at 70MPH and reads 190-200 after sitting in traffic (reading using a nifty temp gauge radiator cap).
    So on Friday I replaced the Avanti clutch fan with a larger 6 blade solid fan. Bingo! Temp gauge read a hair over mid scale at 70MPH, went to 3/4 scale in heavy traffic. Down side, lost power driving that fan and it sounded like a 747 on takeoff at 70MPH.
    Ordered a 14" 1850CFM electric fan (7.5A draw) from Summit https://www.summitracing.com/parts/SUM-G4903/ as well as an adjustable thermostat controller https://www.summitracing.com/parts/FLX-31147/

    I am hopeful that it will be sufficient alone, otherwise it will serve as a backup for the clutch fan.




    If there's anything more important than my ego running around I want it caught and shot now.

  18. #18
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    Pdrnec

    Just a thought or two. But I think my first change to your system would be a shroud. They do an awful lot of good, particularly at low speed.

    The good news, If the electric fan comes with a shroud that fits the radiator then you have killed two birds with the first stone.

    Glad you have made progress to make your car enjoyable to drive.

    Bob
    ,

  19. #19
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    A shroud would be ideal but the fan already sits so high I'm not sure I could make one work
    If there's anything more important than my ego running around I want it caught and shot now.

  20. #20
    Senior Member rockinhawk's Avatar
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    I had similar symptoms with my 81. Turned out to be a bad ground.
    Neil Thornton

  21. #21

    It is me again

    Haven't replaced my gauge yet but not my thermostat is going beyond 240 and pined all to the right and again infrared gun reading are 170 at the head and 160 at the tank. So I am assuming definitely something is going on with my gauge it is pinned all the way to the right pass the 240 mark.

    Thanks
    Rob

  22. #22
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    Probably the sending unit in the back of the head. It's lost it's resistance.

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