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Technical Overheating head scratcher

Discussion in 'Traditional Hot Rods' started by Nebraska Steven, Dec 5, 2018.

  1. Rickybop
    Joined: May 23, 2008
    Posts: 6,378

    Rickybop
    Member
    from Michigan

    Take the fan completely off and go for a ride. I've driven cars with no fan. No biggy. Just don't sit too long.
     
  2. Frankie47
    Joined: Dec 20, 2008
    Posts: 1,727

    Frankie47
    Member
    from omaha ne.

    Your Mopar is rejecting the ford radiator lol .......wish I had more than that for you.
     
  3. Rickybop
    Joined: May 23, 2008
    Posts: 6,378

    Rickybop
    Member
    from Michigan

    Lol. That's gotta be it...
     
  4. sevenhills1952
    Joined: Mar 14, 2018
    Posts: 915

    sevenhills1952

    My 2C is that fan in front of radiator is problem, grill doesn't look like it allows much air flow either. I'm thinking to work properly air has to flow through radiator unrestricted, removing hood doesn't do that.

    Sent from my SM-S320VL using Tapatalk
     
  5. F&J
    Joined: Apr 5, 2007
    Posts: 13,217

    F&J
    Member

    I can't see in that pic...are the outsides of that electric fan ass'y , (beyond the fan blade circle) are they blocked off or are they open? Meaning the corners.

    I'd take it off at this point too, but it looks like a big job on that car. I'd still want to try it though.
     
  6. Mr48chev
    Joined: Dec 28, 2007
    Posts: 26,736

    Mr48chev
    ALLIANCE MEMBER

    I can't see it in the photos that you posted but are the panels in the nose behind the grill and around the radiator that direct the air to the radiator.
    I've run into a couple of engine/radiator swap rigs where the builder left out the panels behind the grill that directed all of the air through the radiator and that let the air flow around the radiator at speed. One thought that the piece that went across the top of the core support on his car blocked the view of his engine too much when he had the hood open at car shows so he left it off letting more air go over the radiator rather than through it The other had cobbled some radiator that didn't fit into the spot and left off a panel because the radiator was in the way letting air flow around the radiator. Another took a hole saw and punched 3 inch holes in the panel for a "race car look" when the hood was open. On that one we figured out that the air was hitting the radiator bouncing back and going through the holes and over the radiator at speed. The last one the guy had cut a big chunk of the panel below the grill out because he did a subframe swap and the whole area below the radiator was open. The air went down and under the car rather than through the radiator.
    Are all of the necessary panels in place so that all of the air going through the grill is going through the radiator at road speed? They don't matter at low speed because the fan still pushes the air though the radiator as it is the air flow but get up to speed and the fast moving air looks for the easiest way to go.
     
    Thommyknocker likes this.
  7. Rickybop
    Joined: May 23, 2008
    Posts: 6,378

    Rickybop
    Member
    from Michigan

    Looks like the fan is round and the radiator is open at the corners. Big fan...blocking the radiator...
     
  8. Nobey
    Joined: May 28, 2011
    Posts: 1,171

    Nobey
    Member

    Looks like you're running a points distributor, check the dwell, check the vacuum advance, also exhaust
    restriction, and leaky head gasket. Some good thoughts from the guys on radiator problems too....
     
  9. Here is something that I don't think has been discussed. Could the lower hose be collapsing at speed??? Does it have a spring in it to prevent it from collapsing??? Does the upper hose have a spring in it ???
     
  10. All panels are in place. Had to make one for the top, but the rest are original.
     
    Mr48chev likes this.
  11. Y
    Lower does, but not upper. It builds plenty of pressure so don't think the upper is an issue.
     
  12. Mopar Performance electronic. I like them because they look like a points distributor!
     
  13. My only thought with the hood, was thinking the motor was blocking air flow. It is nestled in pretty tight to the inner fenders.
     
  14. haha! I have two non mopar parts on the whole car. Radiator and air cleaner! And as a mopar guy, that thought entered my mind.
     
  15. Pulling the radiator is a big job, but the fan is actually pretty easy. This will be my first thing to try once I get some decent weather.
     
  16. trans cooler and fan are restricting the air flow to the radiator
    dodge.jpg
     
  17. G-son
    Joined: Dec 19, 2012
    Posts: 627

    G-son
    Member
    from Sweden

    The trans cooler shouldn't restrict flow since it's so far ahead, air can easily go around it to the radiator. But it does heat the air that goes through it, not ideal (but shouldn't be anywhere near enough to cause this problem alone).

    The fan, being straight on the radiator it can absolutely mask areas of the radiator so air flow is reduced. Removing it is absolutely worth a try.

    Someone said the grille looks small. I think the opposite, it looks big and has plenty of opening to let air through - remember, the radiator has a bunch of tubes and fins that the air has to squeeze between, so even if the radiator is large a huge amount of air can not get through it - not without some serious force, and we don't have that to work with here. The rule of thumb says that you need an opening about 25% of the radiator core area to feed enough air to the radiator, even less at higher speeds. Since you don't get enough pressure to force more air through the radiator the excess air will just spill back out of the opening anyway.

    And another observation... If you have a overheating problem at 45mph you have a problem when using merely 30hp or something like that. Ideally the cooling system should be able to hold temperature at full power for a resonable amount of time, and you are obviously very, very far from that. Even if you improve the cooling to work at 55 or 65mph you'd still have little safety margin for those extra hot summer days, long hills with fully loaded car etc. You might want/need to improve the cooling more than just to barely being enough at the highway.
     
  18. OLDSMAN
    Joined: Jul 20, 2006
    Posts: 2,382

    OLDSMAN
    Member

    Your problem sounds like the problem I have with my convertible. I have a 455 olds with a .030 overbite,griffin aluminum cross flow radiator and at highway speeds with the air on would overheat. Last summer I finally called Mondello, they are the olds gurus. They told me that's the biggest problem they see. They said it's cavitation of the coolant. They suggested a different water pump, so I bought one from them. They also sold a restrictor , so I installed both. What I drove it this fall I think the problem is cured. I will find out when 90 degree weather hits again
     
  19. This was definitely on my list. Hot Heads has a conversion to big block Chevy water pump, but was hoping to avoid. Other people have suggested a restrictor. Is it just an orifice at the radiator inlet?
     
  20. Totally agree with everything you said, and some margin would be nice. Outside temperature does not seem to make much difference in this situation. I have driven it when it is 95 and when its 20 degrees and it is always the same...which is strange.
     
  21. G-son
    Joined: Dec 19, 2012
    Posts: 627

    G-son
    Member
    from Sweden

    Usually the thermostat acts as enough restriction, even fully open it isn't a very big hole. Restricting the flow out of the engine increases coolant pressure inside the engine, reducing problems with hot spots at exhaust ports, combustion chambers etc. where the coolant boils despite not being very hot anywhere else.

    If pump cavitation is a known problem that should be possible to diagnose. It should cause low coolant flow, so the return from the radiator is probably relatively cool. It may very well be rpm related rather than speed/horsepower output related, meaning that the problem may show up at "highway rpm" in a lower gear too. That may also explain why outside temperature isn't a factor. Some pumps work fine at low rpm, and then start cavitating at higher rpm. A problem that probably has caused a lot of head scratching when engines have been tuned, and the cooling issues that followed eventually is cured by changing a belt pulley to run the pump slower.
     
    Last edited: Dec 8, 2018
  22. Ralphies54
    Joined: Dec 18, 2009
    Posts: 718

    Ralphies54
    Member

    My take on your problem is I believe the coolant is flowing through the radiator to fast to allow it to drop in enough temps to keep the eng cool. The faster it flows the hotter it gets and returns to the eng heated beyond the thermostats ability to modulate a consistent temp causing the thermostat to be fully open and allow the engine to heat water to the limit of the pressure cap. Ralphie
     
  23. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 5,000

    Ebbsspeed
    ALLIANCE MEMBER

    Not enough airflow through the radiator would have the exact same symptoms. Besides, the "coolant flowing too fast" myth has been eliminated by simple physics. Read post #23 in the thread below:

    https://www.jalopyjournal.com/forum...ng-too-fast-through-radiator-to-cool.1034655/
     
    ottoman and Nebraska Steven like this.
  24. boring-hop-yard
    Joined: Feb 24, 2008
    Posts: 74

    boring-hop-yard
    Member

    Question, do you have a long hill you could get the car nice and hot, go to the top and coast down with the car in neutral and see if the car cools down. In my opinion this would help identify if you have an issue with the motor or with the Rad. I done this method before and it helps find root cause. Out here in the Northwest we have lots of hills.
    Good luck on your quest.
     
  25. OLDSMAN
    Joined: Jul 20, 2006
    Posts: 2,382

    OLDSMAN
    Member

    It's like a flat washer the size of the thermostat with probably a 5/8 inch hole in it
     
  26. sunbeam
    Joined: Oct 22, 2010
    Posts: 4,799

    sunbeam
    Member

    Some times people miss the easy stuff. If you swap leads DC motors run the other way are you sure the fan is actually blowing the air?
     
    Sandgroper, GuyW and jazz1 like this.
  27. Haha,was actually just wondering if I actually verified that.
     
  28. Thank you to everyone for all the input and ideas. It sounds like my plan of attack should be to get a hold of a temp gun, then should be able tell if the radiator is cooling or not. If it is, then look into the coolant flow issues and possible pump cavitations. If its not, then i will try removing the fan, or convert to puller fan. After that its probably down to a bigger radiator. Now just need some snow to melt and salt to not be on the road. Hopefully I can report back before spring!
     
    firstinsteele likes this.
  29. Blown head gasket?
     
  30. Rickybop
    Joined: May 23, 2008
    Posts: 6,378

    Rickybop
    Member
    from Michigan

    Temp gun? Ok, but the fan...

    Do what sunbeam said first. Check the leads.
    (good one, sunbeam)

    Yes, I agree that it'd be good to use a temp gun and know for sure how the radiator is doing. Maybe it's too small. But jeez...plenty of other powerful cars manage to keep their engines cool in tight confines. And you said it was a new radiator, so I doubt it's clogged. How long did it sit around before you used it? Maybe a mouse got in there and made a nest before you installed it.

    Maybe you can get a temp gun right away.
    But again...the fan.
    Do what I said. Take off the fan and test-drive. And then keep driving...lol.

    If it's still overheating, do what '49 Ford Coupe alluded to. Check for a blown head-gasket..."exhaust streaming"...hot exhaust going directly into the coolant. With no thermostat, the engine cold and the radiator cap off, run the engine and check for bubbles coming to the surface of the coolant in the filler neck.

    Actually, even if one change seems to fix the problem, I would check the other items you haven't yet looked at...exhaust streaming, etc.

    Good luck. Watching to see how it goes for you.
     
    Last edited: Dec 8, 2018
    Maicobreako likes this.

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