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help with overheating 79' 308 USA

Discussion in '308/328' started by Minoru, Oct 11, 2021.

  1. mike996

    mike996 F1 Veteran

    Jun 14, 2008
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    Well, with all the work you have done, I tend to agree that it seems like a radiator problem.

    Do you know if the radiator passages were individually cleaned mechanically by using appropriate sized metal rods through each passage or was the radiator just placed in a hot tank, hoping all the deposits would be loosened/dissolved. To mechanically clean the radiator requires that the end caps be de-soldered/removed and then soldered back in position after cleaning. It's a much bigger (and more expensive) job than simply hot-tanking. But such mechanical cleaning will generally result in a radiator functioning as new. However, sometimes radiators are too far gone for mechanical cleaning and must be replaced.
     
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  3. Minoru

    Minoru Rookie

    Sep 25, 2018
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    Minoru Maeda
    Thanks for your reply. I re-checked the fans and I also add a pull type fan at the back of the radiator. And even though I run the car around 40 mph, the water temp does not go down.
     
  4. Minoru

    Minoru Rookie

    Sep 25, 2018
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    Minoru Maeda
    Thanks for your reply. The radiator professional de-soldered the end caps, and using a new core, he soldered back.
     
  5. 308 milano

    308 milano F1 Rookie
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    RodC328gts asked on Post 14 if temperature gauge is reading correctly? I went back through the entire thread and see nowhere that this was verified with a temp gun.

    * Would purchase a $30 temp gun and verify the temperature around the thermostat housing and compare with gage reading.
    * You mentioned that you replaced the water pump and thermostat fan switch with one from Superformance but sounds like you’re still using the same thermostat? Are you sure the correct thermostat is installed?
     
  6. tuttebenne

    tuttebenne F1 Rookie

    Mar 26, 2003
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    Radiator change makes the most sense.
     
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  8. mike996

    mike996 F1 Veteran

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    Hmm...in that case, maybe the replacement core had less cooling capacity than the original. Doesn't seem likely but per all the other work you stated has been done, the radiator itself is the only thing left ASSUMING the gauge/sensor have been checked to ensure they are indicating reasonably accurate temperatures. IOW, you want to be sure that the problem is actually in the cooling system, not just an inaccurate/inconsistent temp gauge/sensor.
     
  9. Minoru

    Minoru Rookie

    Sep 25, 2018
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    Minoru Maeda
    308 milano, Thanks for your advice.
    I'm quite sure that the temp gauge is OK. I have ever seen the high temp and the engine staled, meaning that the overheat actually occurred.

    This time, I bought three thermostat. Superformance's one, 80C and 71C thermostat. I tested the all with hot water and I confirmed that the all of them opened at the designated temp. Currently, I'm testing using the 71C thermostat.
     
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  10. Minoru

    Minoru Rookie

    Sep 25, 2018
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    Minoru Maeda
    For your better understanding, I think that I need to write the history of the car.
    - I bought and imported this car from USA in 2018. And after through my DIY restoration, the car became to run. At that time, I used Evans.
    - in 2018 mid-summer, when the outer temp was over 95F, I faced the first overheat.
    - in cooler season, the car was OK. (But once I faced the high temp due to the trouble of the fans. so, I replaced them by new high CFM ones.)
    - Avoiding drive under high temp circumstance, the car was OK. I decided to re-core the radiator for future comfortable drive in summer time.
    At the same time, I decided to replace coolant/heater hoses, water pump, thermostat, fan switch just in case. I also added pull type coolant fans.
    Then, I am now facing this issue.
     
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  11. Minoru

    Minoru Rookie

    Sep 25, 2018
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    Minoru Maeda
    Yes, actually the overheat happened. I also faced the engine stall. So, I'm quite sure that the problem is in the cooling system. In order to make sure the cause, I have tested one by one....
     
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  13. 308 milano

    308 milano F1 Rookie
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    Mechanic is not my strong suit.. but if the vehicle got hot enough due to coolant temperature to quit running, I would think it would most probably taken out the head gasket and warped a head on one or both heads? Not sure that would even cause it to quit running. Certainly wouldn’t do it any good.
     
  14. miketuason

    miketuason F1 World Champ
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    A friend of mine has an 85 QV that had an overheating problem, they’ve replace, fix, change all the parts you can think off related to the cooling system and done everything that Maranello have done when they put this car together and it was still overheating. So after further investigation, they end up magnafluxing the block and found out that the block has an hairline crack, changed the block and and overheating is solved.
     
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  15. Minoru

    Minoru Rookie

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    Minoru Maeda
    I also supposed this case. So, I did leak test. But in any cases, the car could run without problem as long as outer temp is not so high just before this work; iow, radiator re-core, change coolant/heater hoses, water pump, thermostat and so on.
     
  16. Minoru

    Minoru Rookie

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    Thanks for the precious information. I think that this is the worst case for me, but if the situation was not improved even though I replaced the radiator by better one, this is the case I should work on. But considering the case that the situation suddenly got worse just after this work, ie, radiator re-core, coolant system refresh, I want to hope this is caused by the radiator.
     
  17. smg2

    smg2 F1 World Champ
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    Please explain the engine stall due to overheating. What actually occurred to stall the engine? What happened when the engine shut off?
     
  18. Minoru

    Minoru Rookie

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    under the scorching sun....
    - Firstly, when I met a traffic jam, I found the water temp gauge went up just before 250F (maybe).
    - I felt power down. When I tried to connect the clutch, I met engine stall. No smoke, no water vapor.
    - I tried to start the engine. It was hard to start.
    - Fortunately, this situation occurred just before a parking lot. I managed to park the car under the shade, I left it several hours to wait sun set.
    - When the outer temp got down, I drove it back home. I had been watching the water temp gauge, but as long as the car was running, I did not face any troubles.
    (After this trouble, as long as I did not drive under the scorching sun, no troubles. )

    As I wrote this, I realized one fact;
    - After the maintenance at this time, the water temp got higher even though the car running.
     
  19. Minoru

    Minoru Rookie

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    FYI I did the follows additionally at this maintenance;
    - I inserted a tube into the upper hose tube of the expansion tank so that it prevents the system gets air from the top area of the expansion tank.
    - I added a reserve tank so that it can keep excess coolant.
     
  20. kcabpilot

    kcabpilot Formula 3

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    Unfortunately in this environment you are going to continue to get advice that is not following the logic of the story because many people will respond but have not read every post. You will also get replies saying they had the exact same problem and the fix was....but that doesn't mean you need the same fix. Troubleshooting is a simple game of elimination. You can do this with tests or logic or a combination of the two but you can't go chasing your tail by listening to people who may have just walked into the room. They may be very knowledgeable but I think everyone should debrief themselves by at least reading the thread in it's entirety so as not to retread covered ground. Troubleshoot like a scientist. Treat the subject as a crime scene and try not to corrupt observations or evidence.

    Eventually you will prevail and solve the problem. d;-)
     
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  21. mike996

    mike996 F1 Veteran

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    Is the ignition timing correct? Retarded ignition can cause overheating.
     
  22. nerofer

    nerofer F1 World Champ

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    Words of Wisdom indeed...

    Rgds
     
  23. mike996

    mike996 F1 Veteran

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    Frankly, per everything the OP has explained, there isn't much left to check as far as the cooling system is concerned. I can't think of a test/check that he hasn't performed ! The radiator core itself is pretty much the last thing left OR some sort of "clog" in the plumbing...but not sure what that could be.

    Obviously SOMETHING is causing the engine to overheat but now I'm wondering about things like the ignition timing I mentioned or an exhaust obstruction...

    In any case, it will be very interesting to find out what the "fix" turns out to be!!
     
  24. 308 milano

    308 milano F1 Rookie
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    From the first post. I’m not sure there is a problem with overheating. Outside temperature above 80°f He states he’s trying to keep the temperature under 195°f while sitting idle.( not possible except for a fall/winter day) Both fans come on and continue to run (which is normal) temperature continues to rise a bit (which again is normal sitting idle). OP states he then shut the car off. Any temperature below 220°f on a hot summer day sitting idle in traffic would seem normal to me but would want to get the car moving again. Also don’t believe the car stalled due to high coolant temperature issue. That would have shown up in leak down test. Guessing stall occurred due to 1979 carb car loading up.
     
  25. mike996

    mike996 F1 Veteran

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    I've read a lot about 308 cooling systems being somewhat marginal compare to the 328 but I wouldn't think 80F outside would be any sort of strain at all on a properly functioning cooling system
     
  26. thorn

    thorn F1 Rookie
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    It's not. 80F is nearly perfect driving weather in Florida.
     
  27. 308 milano

    308 milano F1 Rookie
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    I agree. I think the disconnect here is OP thinks his 308 should run cooler than 195° sitting idle with fans kicking on and off continuously keeping the car below that temperature.
     
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  28. tuttebenne

    tuttebenne F1 Rookie

    Mar 26, 2003
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    Just 11 posts ago, the OP mentioned 250 degrees F. That would seem to me an indication of overheating.
     

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